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Mechanics, Materials Science & Engineering, April 2017 â&#x20AC;&#x201C; ISSN 2412-5954

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Mechanics, Materials Science & Engineering, April 2017 â&#x20AC;&#x201C; ISSN 2412-5954

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Mechanics, Materials Science & Engineering Journal

April 2017

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Mechanics, Materials Sciences & Engineering Journal, Austria, Sankt Lorenzen, 2017 Volume 9, Issue 2

Mechanics, Materials Science & Engineering Journal (MMSE Journal) is journal that deals in peerreviewed, open access publishing, focusing on wide range of subject areas, including economics, business, social sciences, engineering etc.

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Editor-in-Chief Mr. Peter Zisser Dr. Zheng Li, University of Bridgeport, USA Prof. Kravets Victor, Ukraine Ph.D., Shuming Chen, College of Automotive Engineering, China Dr. Yang Yu, University of Technology Sydney, Australia Prof. Amelia Carolina Sparavigna, Politecnico di Torino, Italy Design and layout: Mechanics, Materials Science &

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Mechanics, Materials Science & Engineering, April 2017 â&#x20AC;&#x201C; ISSN 2412-5954

CONTENT Studies on the Growth, Thermal and Optical Properties of p-methyl Anilinium Malate Single Crystal. S. Kalaiyarasi, S. Suresh, R. Mohan Kumar ..................................................................... 8 An Analysis of Structural, Electronic and Reactivity Properties of MetforminChloride using XRD and DFT Approach. R. Niranjana Devi, S. Israel, C. Ancline ............................................ 14 Structural, Spectroscopic, Thermal studies of Pure and DL-Methionine Doped ADP Crystals. J.H. Joshi, H.O. Jethva, P.T. Bagda, K. Ashish Prasad, M.J. Joshi ................................ 20 Impedance Spectroscopy of Sodium Sulphide Added ADP Crystals. A.P. Kochuparampil, J.H. Joshi, H.O. Jethva, M.J. Joshi. .............................................................................................. 25 Growth and Characterization of a Novel Nonlinear Optical Single Crystal of L- Isoleucinium Hydrogen Maleate Hemihydrate. A. Hemalatha, K. Deepa, A. Venkatesan, S. Senthil ............. 31 Group 12-Metal Complexes derived from Donor Substituted Carboxylic Acids and 5-Nitro1,10-Phenanthroline: Spectroscopic and Biological Studies. Champaka Gurudevaru, Nallasamy Palanisami ................................................................................................................. 37 Spectroscopic Properties of Sm3+Doped Lithium Zinc Borosilicate Glasses. N. Jaidass, C. Krishna Moorthi, A. Mohan Babu, M. Reddi Babu .................................................................... 42 Spectral Analysis of Nd3+ Doped Lead Borosilicate Glasses for Efficient Broadband Laser Amplification. M. Reddi Babu, N. Madhusudhana Rao, A. Mohan Babu .................................... 49 Growth and Characterization of a Nonlinear Optical Crystal a Complex Orthonitroaniline with Picric Acid Single Crystal by Vertical Bridgman Technique. S. Noormohammad Shareef, K. Chidambaram, S. Kalainathan ................................................................................................ 54 Studies of Crystal Growth, Structural and Optical Properties of Glycinium-3-Carboxy-4Hydroxybenzenesulfonate Single Crystal. A. Thirunavukkarsu, T. Sujatha, P.R. Umarani, A. Chitra, R. Mohan Kumar .............................................................................................................. 60 Growth and Characterization of L-Glycinium Phosphate: A Promising Crystal for Opto â&#x20AC;&#x201C; Electronics Applications. K. Rajesh, A. Mani, P. Praveen Kumar ............................................... 67 Growth and Characterization of Organo-metallic Single Crystals of (HCLPTM) Heptachloro (L-Proline) TetraMercury (II). V. Revathi Ambika, D.Shalini, R. Usha, N. Hema, D. Jayalakshmi ................................................................................................................................. 73 Comparative Study of Erbium Doped KDP Single Crystals Grown by Different Techniques. V. Roopa, Dr. R. Ananda Kumari ................................................................................................. 78 Crystal Growth, Optical, Dielectric, Mechanical and Second Harmonic Generation Characterization of 2,5-Dimethylanilinium Dihydrogen Phosphate Single Crystal. A. Mani, K. Rajesh, P. Praveen Kumar .......................................................................................................... .93 Comparative Study of Properties of L-Histidine and L-Histidine Nickel Nitrate Hexahydrate Crystals Grown by Slow Evaporation. R. Vinayagamoorthy, A. Albert Irudayaraj, A. Dhayal Raj, S. Karthick, G. Jayakumar..................................................................................... 92 Growth and Characterization of Unidirectional Grown Imidazolium L-Tartrate (IMLT) Single Crystal by SR Method. V. Thayanithi, P. Praveen Kumar ............................................... 98 Growth, Nonlinear, Dielectric Studies on Urea Phosphoric Acid (UP) Single Crystals. N. Hema, R. Usha, D. Shalini, V. Revathi Ambika, D. Jayalakshmi ............................................ 103 Optical, Thermal and Electrical Studies on L-Malic Acid Doped ADP Single Crystals for Non-Linear Optical Application. S. Arulmani, K. Deepa, N. Indumathi, M. Victor Antony Raj, S. Senthil .................................................................................................................................... 108 MMSE Journal. Open Access www.mmse.xyz

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Thermal and Dielectric Properties Of L-Malic Acid Doped KDP Single Crystals. A. Venkatesan, S. Arulmani, E. Chinnasamy, S. Senthil, M.E. Rajasaravanan ................................. 114 Optical, Thermal and Electrical Characterization of Urea Sulphamic Acid Single Crystals. E. Chinnasamy, A.Venkatesan, M.E. Rajasaravanan, S.Senthil ................................................... 120 Crystal Growth, Spectral and Optical Studies of 2-Aminoanilinium Benzoate Single Crystal. I. Md. Zahid1, C. Amirtha Kumar1, R. Mohan Kumar ................................................................ 126 Synthesis, Vibrational Spectroscopy, Thermal Analysis, Non-Linear Optical Properties and DFT Calculation of a Novel L-Phenylalanine Maleic Acid Single Crystals. K. Deepa, J. Madhavan .................................................................................................................................. 131 Piezoelectric and Ferroelectric Properties of Lead-free 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 Solid Solution. S. Sasikumar, R. Saravanan, S. Saravanakumar ................................................ 137 Synthesis and Physicochemical Investigation of THz Material: 4–Ethoxy Benzaldehyde–4'– N'–Methyl Stilbazolium Hexafluorophosphate (EMBSHP). A. Karolin Martina1, J. Arul Martin Mani1, N.S. Nirmala Jothi1, P. Sagayaraj .................................................................................. 145 Recycling Technology of Fiber-Reinforced Plastics Using Sodium Hydroxide. K. Baba, T. Wajima .................................................................................................................................. 150 Synthesis, Growth and Optical, Electrical, Thermal Properties of L- Proline Adipate Single Crystals for Nonlinear Optical Applications. N. Indumathi, K. Deepa, J. Madhavan, S. Senthil .................................................................................................................................... 156 Synthesis, Growth, Spectral, Thermal and Mechanical Properties of Inorganic – Organic Hybrid NLO Crystal: NH4[Cd(NCS)3] C12H24O6. V. Ramesh, K. Rajarajan ....................... 162 Synthesis, Growth and Characterization Aspects of Non-linear Organometallic Single Crystals of BCTZ. K.Showrilu, V.Naga Lakshmi, K.Rajarajan .................................................. 168 Crystal Growth, Spectral and Optical Properties of Quinolinium Single Crystal: 1-Ethyl-2[2-(4-Nitro-Phenyl)-Vinyl]-Quinolinium Iodide. S. Karthigha, C. Krishnamoorthi .................. 174 Synthesis, Growth, Spectral, Optical and Mechanical Properties of an Organic Single Crystal: (E)-2-(4-Chlorostyryl)-1-Methylpyridin-1-Ium Iodide Hydrate. K. Nivetha, W. Madhuri ................................................................................................................................. 179 Theoretical Investigation of Optical and Mechanical Properties of Sodium Hydrogen Succinate Single Crystal: a Third Order NLO Material. P.S. Latha Mageshwari, R. Priya, R. Subhashini, V. Joseph, S. Jerome Das ......................................................................................... 184 Crystal Structure, Dielectric Response and Thermal Analysis of Ammonium Pentaborate (APB). Hiral Raval, Mitesh Solanki, Bharat Parekh, M.J. Joshi ................................................. 190 Investigation on Thermal, Optical, Second Order and Third Order NLO Properties of a Nonlinear Optical Single Crystal of L-Leucinium Hydrogen Maleate (LLM). Hemalatha, S. Senthil ........................................................................................................................................ 196 Growth and Dielectric Properties of 1,3-bis(4-methoxyphenyl)prop-2-en-1-one Organic Single Crystal. K. Arunkumar, S. Kalainathan .......................................................................... 202 Effect of Hydrochloric Acid (HCl) on Synthesis and Anisotropic Phenomena of Triglycine Phosphate (TGP) Single Crystals. M.R. Meera, S.L. Rayar, V. Bena Jothy .............................. 208 Structural Properties of Bioactive Molecule Naphthalene 2-Sulfonic Acid. R. Mini, T. Joselin Beaula, I. Hubert Joe, V. Bena Jothy .......................................................................................... 215

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Fluorescence Emission and Decay Time Studies on Doped 1, 3, 5-Triphenylbenzene Scintillator Crystal Grown by Solution Growth Technique. N. Durairaj, S. Kalainathan, R. Kumar ................................................................................................................................... 220 Bulk Crystal growth and Characterization of Organic Nonlinear Optical Crystal: 2-(2,4dimethoxybenzylidene) malononitrile (DMM). A. Priyadharshini, S.Kalainathan .................. 225 Growth and Etching Studies of Cadmium Mercury Thiocyanate Single Crystals Grown by Gel Technique. P. Nisha Santhakumari, S. Kalainathan ............................................................ 230 Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties. S. Karthick, A. Albert Irudayaraj, A. Dhayal Raj, R. Vinayagamoorthy ................... 235 Laser Hardening and Pack Boriding of EN 8D Steel. K. Monisha, P. Selvamuthumari, D. Narendran, Rasik Ahmad Parray, J. Senthilselvan ................................................................. 240 Synthesis, Growth and Characterisation of New Organic Crystal: L-Histidinium 5 Sulfo Salicylate for Second Order Nonlinear Optical Applications. R. Usha, N. Hema, V. Revathi, Ambika D. Shalini, D. Jayalakshmi ............................................................................................ 244 Investigation on Zn (II) Doped Lithium Sulphate Monohydrate Single Crystals. E. Glitta Sumangali, Girish M. Joshi ........................................................................................................ 250 Gel Growth: A Brief Review. H.O. Jethva ......................................................................... 255 Importance of Impedance Spectroscopy Technique in Materials Characterization: A Brief Review. M.J. Joshi ..................................................................................................................... 261 A Combined Experimental and Theoretical Investigations on N, N′-Diphenylguanidine Based Single Crystals For Nonlinear Optical Applications. G. Saravana Kumar, R. Roop Kumar, P. Murugakoothan. .................................................................................................................... 267 Facile Preparation and Characterization of Polyaniline-iron Oxide Ternary Polymer Nanocomposites by Using “Mechanical Mixing” Approach. N. Dhachanamoorthia, L. Chandra, P. Suresh, K. Perumal ................................................................................................................ 273 Experimental Investigation of Static Mechanical Properties of Epoxy Based Glass, Carbon & Sisal Woven Fabric Hybrid Composites. M. Arulkumar, K.S. Rajeshwaran, G. Sathish ...... 281 Structural and Complex Formation of PVC – LiNO3 – CdO. . Karthika, R. Karthigai Selvi, P.S. Devi Prasadh. ..................................................................................................................... 287 Investigation of Surface Texture Generated by Friction Drilling on Al2024-T6. M. Boopathi, S. Shankar, T.C. Kanish. ............................................................................................................ 291 Mechanical Properties of Natural Fiber Sandwich Composite: Effect of Core Layer. M. Rajesh, T.C. Kanish .............................................................................................................. 296 Fabrication of Hybrid Metal Matrix Composite Reinforced With SiC/Al2O3/TiB2. S. Johny James, A. Raja Annamalai, P. Kuppan, R. Oyyaravelu. .................................................... 301 Fabrication of Aluminium Metal Matrix Composite and Testing of Its Property. S. JohnyJames, A. Raja Annamalai. ............................................................................................... 306 Determination of Activation Energies from Complex Impedance Parameters of Microwave Sintered NiMgZn Ferrites. K. Chandra Babu Naidu, W. Madhuri. .......................................... 312 Structural and Dielectric Properties of CuO, PbO and Bi2O3 Doped SrTiO3 Ceramics. T. Sofi Sarmash, V. Narasimha Reddy, T. Vidya Sagar, M. Maddaiah, T. Subbarao. ............................................................................................................................. 318

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Multiwalled Carbon Nanotubes (MWCNT) / Poly O-Cresophthalein Complexone Film (POCF) Modified Electrode for Determination of Cd (ll) Using Anodic Stripping Voltammetry. J. Jayadevimanoranjitham, C. Lakshmi Devi, S. Sriman Narayanan. .................. 324 Spectroscopic Analysis of Gas Phase Astrophysical Molecule: Beryllium Monofluride. R. Sindhan, P. Sriramachandran, R. Shanmugavel, S. Ramaswamy. ........................................... 329 Study of Charge Density and Crystal Structure of co-doped LaCrO3 System. N. Thenmozhi, S.Sasikumar, R. Saravanan, Yen-Pei Fu. .................................................................................... 335 Electrical Properties of Ni0.4Mg0.6Fe2O4 Synthesized by Conventional Solid-State Reaction Method. K.T. Veeranjaneaya, D. Ravinder. ............................................................................... 343 Synthesis and Characterization of PbZrTiO3 Ceramics. T. Vidya Sagar, T. Sofi Sarmash, M. Maddaiah, T. Subbarao. ........................................................................................................ 348 Effect of Multiple Laser Shock Peening without Coating on Al-2024-O Alloy for Automotive Applicatio. Yash Jain, Sandeep Varin, S. Prabhakaran, S. Kalainathan. ................................... 353 Influence of Multiple Laser Shock Peening without Coating on Ti-6Al-4V Alloy for Aircraft Applications. Sandeep Varin, Yash Jain, S. Prabhakaran, S. Kalainathan. ................................ 358 Analytical Quality by Design – A Legitimate Paradigm for Pharmaceutical Analytical Method Development and Validation. Balaji Jayagopal1, Murugesh Shivashankar. ............................. 364 Effect of Laser Shock Peening Without Coating on Surface Morphology and Mechanical Properties of Nickel-200. Aniket Kulkarni, Siddarth Chettri, S. Prabhakaran, S. Kalainathan. .......................................................................................................................... 374 Characterization of Cr Doped CuGaS2 Thin Films Synthesized By Chemical Spray Pyrolysis. N. Ahsan, S. Kalainathan, N. Miyashita, T. Hoshii, Y. Okada. .................................................... 380 Deposition and Characterisation of Zinc Telluride as a Back Surface Field Layer in Photovoltaic Applications. Srimathy N., A. Ruban Kumar. ....................................................... 388 Phtotocatalytic Degradation of Methyelene Blue by Cu Doped TiO2 Thin Films under Visible Light Irradiation. Vidhya Rajendran, Gandhimathi Rajendran, Neyvasagam Karuppathevar. ..................................................................................................... 395 Highly Porous and Novel 1D-TiO2 Nanoarchitecture with Light Harvesting Morphology for Photovoltaic Applications. K. Pugazhendhi, W. Jothi Jeyarani, Tenzin Tenkyong, P. Naveen Kumar, B. Praveen,J. Merline Shyla. ...................................................................................................... 402 Application of Quaternionic Matrices for Finite Turns’ Sequence Representation in Space. Victor Kravets, Tamila Kravets, Olexiy Burov. ........................................................................... 408

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Studies on the Growth, Thermal and Optical Properties of p-methyl Anilinium Malate Single Crystal1 S. Kalaiyarasi1, S. Suresh1, R. Mohan Kumar1 1 – Department of Physics, Presidency College, Chennai, India DOI 10.2412/mmse.83.31.489 provided by Seo4U.link

Keywords: organic compound, solution growth, photoluminescence, nonlinear optical studies.

ABSTRACT. Single crystal of a novel p-methyl anilinium malate (PTM) was grown by slow evaporation method. Single crystal and powder X-ray diffraction studies confirm that PTM belongs to monoclinic system with centro-symmetric space group P21/c. FTIR spectral analysis showed the presence of functional groups in PTM compound. Thermal studies exhibit that PTM crystals are stable up to 166⁰C. UV-visible study showed the good transmission region, cut-off wavelength (206 nm) and band gap energy (5.8 eV) and photoluminescence studies explored its efficacy towards device fabrication. The third order nonlinear optical parameters such as the nonlinear refractive index (n 2) = 3.41 × 10−8 cm2/W, nonlinear absorption coefficient () =0.03 × 10−4 cm/W and third order nonlinear susceptibility ((3)) = 3.77 × 10−6 esu of PTM crystal were estimated by using Z-scan measurement.

Introduction. Recently, much attention has been paid on the development of a novel nonlinear optical (NLO) materials because of their optical applications, such as optical data storage, electrooptical modulation, optical switching, optical frequency doubling and optical communication. The organic compounds are having high nonlinear optical susceptibility (χ) than inorganic materials. The organic materials contain proton acceptor and donor groups positioned at either end of a suitable conjugation path. The efficient optical switching behaviour of third order nonlinear optical organic materials was investigated in recent years. The aim for designing the molecules with high third-order nonlinearity is to incorporate them into device applications. 4-methylaniline contains a proton acceptor amino (NH2) group, which can creates a strong hydrogen bond with organic acids and forms N-H--O, an anilinium group [1]. DL-malic acid one of the simplest chiral dicarboxylic acids, is a suitable building block in crystal engineering and it is used to create two-dimensional anionic networks held together by hydrogen bonds [2]. The structure of the p-methyl anilinium malate compound has been reported [3]. The systematic investigation has been carried on the growth aspects of PTM crystal. The spectral, optical, thermal properties of PTM crystal were studied by using various characterization techniques and results are reported. Material synthesis and crystal growth. p-methyl anilinium malate compound was synthesized nfrom high pure p-toluidine (sigma-Aldrich 99.6%) and malic acid. Equimolar amounts of reactants were fully dissolved in deionized water. The solution was continuously stirred for obtaining homogeneous state and the solution was allowed for evaporation by using a constant temperature bath. After the period of 30 days, a good quality of single crystal was harvested with dimension 14x3x2 mm3as shown in Fig. 1.

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Fig. 1. Photograph of PTM crystal. Results and discussion X-ray diffraction studies. The single crystal X-ray diffraction study was performed using MoKα radiation from X-ray diffractometer. The estimated cell parameters values of PTM crystal are a = 7.4849 Å, b = 16.1306 Å, c = 10.4904 Å, α = γ = 90⁰, β =109.23⁰, V = 1195.9 Å3 and Z=4. It was found that the grown crystal belongs to monoclinic system with space group P2 1/c. The powder X-ray diffraction of the grown crystal was recorded from 10⁰ to 50⁰ by using CuKα radiation of wavelength 1.5406 Å (Fig.2). The hkl values of prominent planes were indexed. (0 3 1)

800 700

(0 0 4)

200

(1 5 1)

300

(2 0 0)

400

( 1 2 3)

(2 1 1)

500

(1 3 1)

Intensity (Cps)

600

100 0 -100 10

2 (Degree)

Fig. 2. Powder X-ray diffraction pattern of PTM crystal. FTIR spectral studies. Fourier transform infrared spectrum of PTM was recorded in the range 400-4000 cm-1 by KBr pellet method (Fig.3). The presence of functional groups in the synthesized compound was ascertained and corresponding frequency assignments are given in Table 1. FT-IR spectrum of PTM crystal shows a band at 3432 cm-1 which is assigned to N-H stretching vibrations. The asymmetric and symmetric stretchings observed at 2990 and 2605 cm-1 are due to C-H vibrations. The presence of carboxylate ions confirmed through the asymmetric and symmetric stretching vibrations of COO- at 1591 and 1422 cm-1 respectively. The deformation and wagging vibrations of N-H group yielded peaks at 1243 and 1084 cm-1. The infrared bands appeared at 878 and 803 cm-1 is attributed to C-C stretching vibrations. The absorption occurred at 597, 548 and 484 cm-1 is

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

characteristics of COO- wagging mode and supports the protonation and the deprotonation of title compound. 100

50 40 30 20 4000

3500

3000

2500

2000

1500

643 597

1000

548

484

1168 1084 1028 943 878 803

1695 1591 1516 1422 1301 1347 1234

2990

2605

756

3432

Transmittance (%)

500

Wavenumber (cm-1)

Fig. 3. Infrared spectrum of PTM. TG-DSC analysis. From the TG-DSC curves (Fig.4), it was observed that, the title compound is thermally stable upto 166⁰C and the DSC thermal study confirms that the PTM crystal melts at 167°C.There was no major weight loss occured before 167° C. The weight loss started at 167°C due to the liberation of volatile substances such as CO, CO2 and hydrocarbons. The final stage of decomposition started at 215⁰C and it prolonged upto 315⁰C. From these results, it was concluded that the PTM crystal is capable to function at temperature upto 166⁰C which could be useful in optical applications. B C

100

2 80

0 -1

-2

DSC (mW/mg)

Weight (%)

20 -3 0

-4 0

100

200

300

400

500

600

700

Temperature (C)

Fig. 4. TG-DSC Thermogram of PTM. UV-Visible transmission studies. From the UV-Visible optical studies, the transmission range, transparency, absorption coefficient band gap energy were estimated which are the important parameters for optical applications. UV-vis spectrum of PTM showed good transparency about 72% with lower cut-off wavelength 206 nm. The optical band gap energy (Eg ) was estimated using (Eqn.1), and it was found to be 5.8 eV as shown in Fig.5(a) and (b). MMSE Journal. Open Access www.mmse.xyz

Mechanics, Materials Science & Engineering, April 2017 â&#x20AC;&#x201C; ISSN 2412-5954

(ÎąhĎ&#x2026;)2 = A (Eg â&#x20AC;&#x201C;hĎ&#x2026;)

(1) a

Fig. 5. (a) UV-Visible transmission spectrum (b) Taucâ&#x20AC;&#x2122;s plot of PTM crystal. Photoluminescence spectral studies. Photoluminescence spectrum was recorded for PTM crystal at room temperature with an excitation wavelength of 250 nm as shown in Fig.6. The sharp spectrum showed a peak centered at 355 nm and no other visible emission peak has been observed. In the present study, a very strong intense emission peak observed at 355 nm (E g = 3.4 eV) corresponds to near band-edge exitons of as-gown crystal. It may be occurred due to the n â&#x2020;&#x2019; đ?&#x153;&#x2039;* transition. Therefore, the PTM crystals might be suitable for UV filters and optoelectronic laser devices [4].

700000

355 nm

600000

Intensity (a.u)

500000 400000 300000 200000 100000 0 -100000 250

300

350

400

450

500

550

600

650

Wavelength (nm)

Fig. 6. PL spectrum of PTM crystal with an excitation wavelength of 250 nm. Nonlinear optical studies. Third order nonlinear optical property of PTM crystal has been investigated by Z scan technique and it is an exact method to find the sign and magnitude of nonlinear refractive index (n2) and nonlinear absorption coefficient (Î˛) of the sample. It is the single beam MMSE Journal. Open Access www.mmse.xyz

Mechanics, Materials Science & Engineering, April 2017 â&#x20AC;&#x201C; ISSN 2412-5954

method, which utilizes self focusing or self defocusing phenomena in optical nonlinear materials [5]. The Z-scan measurement traces in closed aperture mode and open aperture are shown in Fig. 7(a) and Fig. 7(b) respectively. The third order nonlinear optical susceptibility was calculated using the relation, Ď&#x2021;(3)= â&#x2C6;&#x161;(đ?&#x2018;&#x2026;đ?&#x2018;&#x2019; đ?&#x153;&#x2019; (3) )Â˛ + (đ??źđ?&#x2018;&#x161; đ?&#x153;&#x2019; (3) )Â˛

(2)

The third-order nonlinear refractive index (n2) = 3.41 Ă&#x2014; 10â&#x2C6;&#x2019;8 cm2/W, nonlinear absorption coefficient (ď ˘) =0.03 Ă&#x2014; 10â&#x2C6;&#x2019;4 cm/W and third order non-linear susceptibility (ď Ł(3)) = 3.77 Ă&#x2014; 10â&#x2C6;&#x2019;6 esu were estimated by Z- scan technique. 1.5 1.04

Normalised transmittance

closed aperture 1.4 1.3 1.2 1.1 1.0 0.9 0.8

open aperture

b 1.03

1.02

1.01

1.00

0.7 -15

-10

-5

-15

-10

Z(mm)

-5

Z(mm)

Fig. 7 (a) Z-scan plot of PTM crystal in closed aperture (b) Z-scan plot of PTM crystal in open aperture. Summary. Third-order nonlinear optical PTM single crystal with 14x3x2 mm3 dimension was grown by slow evaporation technique. Single crystal X-ray diffraction studies reveal that the grown PTM crystal belongs to monoclinic system with P21/c space group. The functional groups present in PTM were confirmed by FTIR spectral studies. TG-DSC thermogram revealed the thermal stability of PTM crystal. UV-visible study showed the good transmission region and the cut-off wavelength, band gap energy were found to be 206 nm and 5.8 eV respectively. Photoluminescence spectral analysis suggests that PTM could be used in UV filters and optoelectronic devices. Z-scan measurements revealed the values of third-order nonlinear refractive index, nonlinear absorption coefficient and third order non-linear susceptibility. References [1] J.V. Jovita, K. Boopathi, P. Ramasamy, A. Ramanand, P. Sagayaraj, Synthesis, growth and characterization of 4-methyl anilinium phenolsulfonate single crystal, J. Cryst. Growth, Vol. 380, pp. 218-223, 2013, DOI: 10.1016/j.jcrysgro.2013.06.027. [2] A. Senthil, P. Ramasamy, Synthesis, growth and characterization of strontium bis (hydrogen lmalate) hexahydrate bulk single crystal: a promising semi-organic nonlinear optical material, J. Cryst. Growth, Vol. 312, pp. 276-28, 2010, DOI: 10.1016/j.jcrysgro.2009.10.021.

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[3] S. Kalaiyarasi, S. Reena Devi, R. Akilan, R. Mohan Kumar, G. Chakkaravarthi, 4Methylanilinium 3-carboxy-2-hydroxypropanoate, IUCrData, Vol.1(9), pp.1,x161525, 2016, DOI:10.1107/S241431461601525X. [4] S. Sudhahar, M. KrishnaKumar, A. Silambarasan, R. Muralidharan, R. Mohan Kumar, Studies on structural, spectral, and optical properties of organic nonlinear optical single crystal: 2-Amino4,6-dimethylpyrimidinium p-Hydroxybenzoate, J. Mater., 2013, DOI: org/10.1155/2013/539312 [5] V. Subashini, S. Ponnusamy, C. Muthamizhchelvan, Synthesis, growth, spectral, thermal, mechanical and optical properties of piperazinium (meso) tartrate crystal: A third order nonlinear optical material, J. Cryst. Growth, Vol. 363, pp. 211-219, 2013, DOI: 10.1016/j.jcrysgro.2012.10.045. Cite the paper S. Kalaiyarasi, S. Suresh, R. Mohan Kumar, (2017). Studies on the Growth, Thermal and Optical Properties of p-methyl Anilinium Malate Single Crystal. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.83.31.489

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Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

An Analysis of Structural, Electronic and Reactivity Properties of MetforminChloride using XRD and DFT Approach2 R. Niranjana Devi1, S. Israel1, C. Ancline1 1 – Research and post graduate department of Physics, The American College, Madurai – 625002, Tamilnadu, India DOI 10.2412/mmse.19.50.462 provided by Seo4U.link

Keywords: charge, reactivity, electrophilicity index, electrophilic region, electrostatic potential

ABSTRACT. In this work, crystallization of first-line antidiabetic drug MetforminChloride has been done by slow evaporation method and the structure has been re-determined at 100K and the most thermodynamically stable phase A has been obtained. Experimentally and theoretically obtained structures and their parameters match well. With the goal of understanding the nature and reactivity of the molecule, some reactivity descriptors such as ionization energy, electron affinity, HOMO-LUMO energy gap, chemical potential, molecular softness, hardness and electrophilicity index has been calculated using Density functional theory with the basis set B3LYP/6-311++G(d, p). In order to get insight into the electronic charge distribution in a molecule, Mulliken, AIM and Natural charges have been calculated and electrostatic potential has been visualized to identify the sites of electrophilic and nucleophilic regions where the molecular interactions likely to happen. The dipole moment has been calculated to predict the shape and polarity of the molecule. The NBO analysis has been carried out to obtain information about the hyper conjugative interaction and electron density transfer from the filled lone pair electron to the bonding orbitals. The docking study of Metformin cation with the 1FM9 protein has been carried out to better understand the drug-receptor interaction.

Introduction. Metformin Chloride(MET/Cl) is known as potent drug in the treatment of type2 noninsulin-dependent diabetes mellitus[1]. The mechanism of the drug is alleviating hepatic glucose production as well as increasing insulin sensitivity. This is also known as anti-hyperglycemic drug as it reduces the risk of cardiovascular mortality without inducing hypoglycemia[2]. The investigation on the structural, electronic, nature and reactivity of the MET/Cl molecule leads us not only to obtain better knowledge about the existing drug but also paves way for the design of new potential and efficient drugs. In that sense this study throws light into the structure related things, charges, HOMO(Highest occupied molecular orbital)-LUMO(Lowest unoccupied molecular orbital) analysis, NBO analysis, electrostatic potential and dipole moment in order to obtain better interpretation on the character and reactivity properties of the MET/Cl molecule. Methodology Experimental. Crystallization of MET/Cl has been done using slow evaporation technique and needle shaped crystal have been harvested. The structure has been re-determined at 100K and the most thermodynamically stable phase A has been obtained. Theoretical details. Using GAUSSIAN09 [3] software, the optimization of structure of MET/Cl has been done at B3LYP level with the basis set 6311G++(d, p) to obtain minimum energy structure. The equilibrium structure has been achieved with the absence of imaginary frequency. Results and discussion Structural details. The optimization yields the results that MET/Cl molecule has 22 atoms and it has 60 degrees of freedom. The structure has one Metformin cation and one Chlorine anion. Especially the metformin cation consists of three amine(-NH2) groups and two methyl(-CH3) groups linked © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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through alternate C-N bonds. The optimized structure clearly shows the occurrence of delocalization among the C-N bonds. The nuclear repulsion energy has been found to be 661.70 Hatrees. The optimized structure of MET/Cl was shown in figure1.

Fig. 1. Optimized Structure of MET/Cl. Atomic charges Analysis on the atomic charges provides information on charge distribution in the molecule and this describes the process of electronegativity equalization and charge transfer in chemical reactions. In order to get better perspective on charge distribution the comparison of Mulliken charges[4], AIM[5] and Natural population analysis[6] has been done and is given in Fig.2. Mulliken Population Analysis [4] based on the linear combination of atomic orbitals is the study of charge distribution within molecules, which partitions the total charge among the atoms in the molecule with its sign and magnitude while AIM charges[5] are based on charge density distribution. According to the results of the three analyses, all nitrogen N11, N12, N13, N14, N15 and Cl22 atoms carry negative charges. 1.8 AIM MPA NPA

1.3

Charges

0.8

0.3

-0.2

-0.7

-1.2 C1

H3 H2

C5 H4

H7 H6

C9 H8

N11 C10

N13

N12

N15

N14

H17

H16

H19

H18

H21

H20

Cl22

Atoms

Fig. 2. Plot of atoms and charges from AIM, MPA and NPA analysis. Nature and chemical reactivity Frontier molecular orbital theory is an application of Molecular Orbital theory which describes the HOMO (Highest occupied molecular orbital) and LUMO (Lowest unoccupied molecular orbital) interactions and the bonding nature in terms of wave characteristics of electrons. Notably the HOMOLUMO analysis has been carried out to explain the charge transfer within the molecule. The HOMO and LUMO energies were calculated by the standard basis set B3LYP/6-311G++ (d, p) where HOMO MMSE Journal. Open Access www.mmse.xyz

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state is found at -0.214a.u. and LUMO is found at -0.039a.u. The HOMO-LUMO isosurface maps and energy level graph of the molecule is given in Fig.3. DFT has become an efficient tool to provide theoretical insights into the chemical reactivity and site selectivity in terms of popular qualitative chemical concepts like electronegativity (Ď&#x2021;), chemical hardness (Îˇ), softness(S), chemical potential (Îź), and electrophilicity index (Ď&#x2030;). By Koopmansâ&#x20AC;&#x2122; theorem [7] ionization potential (I)[8], electron affinity(A)[9], electronegativity(Ď&#x2021;)[10], hardness (ď ¨)[11], softness(S)[12] which are based on the energy of the HOMO and the LUMO.

ď ¨ =

1 1 (đ??ź â&#x2C6;&#x2019; đ??´) = (đ?&#x153;&#x20AC;đ??ťđ?&#x2018;&#x201A;đ?&#x2018;&#x20AC;đ?&#x2018;&#x201A; â&#x2C6;&#x2019; đ?&#x153;&#x20AC;đ??żđ?&#x2018;&#x2C6;đ?&#x2018;&#x20AC;đ?&#x2018;&#x201A; ) 2 2 1

đ?&#x153;&#x2021; = â&#x2C6;&#x2019; 2 (đ??ź + đ??´) = â&#x2C6;&#x2019; 2 (đ?&#x153;&#x20AC;đ??ťđ?&#x2018;&#x201A;đ?&#x2018;&#x20AC;đ?&#x2018;&#x201A; + đ?&#x153;&#x20AC;đ??żđ?&#x2018;&#x2C6;đ?&#x2018;&#x20AC;đ?&#x2018;&#x201A; ) đ?&#x153;&#x2019;=

đ??ź+đ??´ 2

where đ??ź = â&#x2C6;&#x2019;đ?&#x153;&#x20AC;đ??ťđ?&#x2018;&#x201A;đ?&#x2018;&#x20AC;đ?&#x2018;&#x201A; đ?&#x2018;&#x17D;đ?&#x2018;&#x203A;đ?&#x2018;&#x2018; đ??´ = â&#x2C6;&#x2019;đ?&#x153;&#x20AC;đ??żđ?&#x2018;&#x2C6;đ?&#x2018;&#x20AC;đ?&#x2018;&#x201A; Where I and A are the ionization potential and electron affinity of the molecules respectively. The DFT method predicts that the HOMO â&#x20AC;&#x201C; LUMO energy gap of MET/Cl is 0.175a.u. which is found to be very low and it leads to less stability of the molecule and it is more polarizable as the frontier orbital gap is small and is associated with low kinetic stability, high chemical reactivity. The low ionization energy 0.214a.u. of MET/Cl shows that the molecule is highly reactive. Electronegativity measures the power of an atom to attract electrons to it. The target molecule has electronegativity of 0.126a.u. and so it has low capacity of attracting electrons from the neighboring molecules. Softness is used to measure the extent of chemical reactivity and is the measure of the capacity of an atom or group of atoms to receive electrons [12]. It is the reciprocal of hardness. S = 1/ 2ď ¨ The calculated softness value for this molecule is very high and is found to be 5.715a.u. and this states that the molecule is very soft. Notably if the HOMO and the LUMO are close together, the absolute hardness is low and the atoms or molecules are ready to share the electrons to create the covalent bond. The title molecule has very low HOMO â&#x20AC;&#x201C; LUMO energy gap of 0.175a.u. which forms a strong bond with other polarizable molecule. This is the most desirable property for any possible intermolecular interaction between a pharmaceutical compound and a bio molecule and a tool to forecast whether the molecule is a fast interacting drug or not. Moreover MET/Cl has very less toxicity as the electrophilicity index [13] is very low (0.090a.u.).

EHOMO = -0.214a.u.

Î&#x201D;E= -0.175a.u.

EHOMO = -0.039a.u.

Fig. 3. Plots of HOMO, LUMO and energy gap of MET/Cl. MMSE Journal. Open Access www.mmse.xyz

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The reactivity descriptors have been listed in Table 1. Table 1. Reactivity descriptors of MET/Cl molecule. Reactivity descriptor

Energy(a.u.)

Electron affinity

Reactivity descriptor

Energy(a.u.)

Electronegativity

A=[-ELUMO]

0.039

Ionization potential

χ=(I+A)/2

0.126

Electrophilicity index

I=[-EHOMO]

0.214

Global hardness η=(I-A)/2

0.088

ω=μ2/2η

0.090

HOMO energy

-0.214

LUMO energy

-0.039

softness S=1/2η

5.715

Electrostatic potential and docking analysis The electrostatic potential is very effective tool to predict the reactive sites of the molecule with the target molecule[14]. The Fig.4a clearly shows the electrophilic and nucleophilic regions of the MET/Cl molecule. The large electronegative region(red colour isosurface) is found in the vicinity of the Cl anion which is susceptible to electrophilic attack and large positive region(blue colour isosurface) is seen on the MET cation which is prone to nucleophilic attack. The interaction of drug with protein(Fig.4b) can be understood through docking analysis. Interaction of the Metformin drug with the amino acid residues present in the 1FM9 protein. The N atoms are interacting with the amino acid residues such as Hn, Hg1, Hz2 present in the 1FM9.

Fig. 4. a) View of electrostatic potential of MET/Cl b) Interaction of metformin cation with the amino acid residues of 1FM9 protein. NBO Analysis The NBO analysis provides information on the intermolecular interactions of the molecule and it plays vital role in interpreting the hyper conjugative interaction and electron density transfer from the filled lone pair electron[15]. The condition for occurring intra-molecular charge transfer is the orbital overlap between bonding(σ) and non-bonding(σ*) orbital which stabilizes the system. Table2 gives MMSE Journal. Open Access www.mmse.xyz

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the Second order perturbation theory analysis of Fock matrix in NBO basis corresponding to the intramolecular of the MET/Cl compound. The interaction of σ(C1 - H2) with the σ*(C5 - N11) takes the highest hyperconjugative energy and is found to be 3.72kcal/mol. The interaction between the bonding σ(C5-H6) and anti-bonding σ*(N11) takes the lowest hyper conjugative energy, 0.51kcal/mol. Table 2. Donor and acceptor NBO and energy details of MET/Cl. Donor

Acceptor

E(2)a

NBO(i)

NBO(j)

kcal/ mol

E(j)E(i) b

F(i,j) c

Donor

Acceptor

E(2)a

a.u.

NBO(i)

NBO(j)

kcal/

a.u.

mol

E(j)E(i) b

F(i,j) c a.u.

a.u.

σ(C1 - H2)

σ*(C5 - N11)

3.72

0.85

0.050

σ(C9 - N13)

σ*(C10)

2.59

1.95

0.064

σ(C1 - H3)

σ*(C9 - N11)

2.74

1.02

0.048

σ(C10 - N1)

σ*(N13)

0.82

1.61

0.033

σ(C1 - H4)

σ*(N11)

0.68

1.32

0.027

σ(C10 - N15)

σ*(N13)

0.53

1.62

0.026

σ(C1 – N11)

σ*(C5)

0.76

1.48

0.030

σ(N12 - H16)

σ*(C9)

0.55

1.86

0.029

σ(C5 - H6)

σ*(N11)

0.51

1.31

0.023

σ(N12 - H17)

σ*(C9)

1.95

1.87

0.054

σ(C5 - H7)

σ*(C9 - N11)

3.38

1.02

0.053

σ(N14 - H18)

σ*(C10)

0.84

2.25

0.039

σ(C5 - H8)

σ*(C1 - N11)

3.21

0.85

0.047

σ(N14 - H19)

σ*(C10)

1.43

1.80

0.045

σ(C5 - N11)

σ*(C1)

0.78

1.52

0.031

σ(N15 - H20)

σ*(C10)

1.78

1.75

0.050

σ(C9 - N11)

σ*(C1)

0.75

1.65

0.032

σ(N15 - H21)

σ*(C10)

0.93

1.77

0.036

σ(C9 - N12)

σ*(C1 - N11)

3.61

1.17

0.058

E(2)a refers energy of hyperconjugative interaction; E(j)-E(i) b refers energy difference between donor and acceptor i and j NBO orbitals; F(i,j) c refers the Fock matrix element between i and j NBO orbitals. Summary. This study gives clear picture about the structure, electronic properties, nature, chemical reactivity and molecular electrostatic potential of the biguanide MET/Cl. The three analyses of charges report that all the N atoms have negative charges and especially the Cl anion has the highest negative charge. The molecule is very soft in nature and highly polar molecule, less toxic when compared to the other biguanides, highly chemically reactive and a fast interacting drug. The Cl anion is susceptible to electrophilic attack and the MET cation is susceptible to nucleophilic attack. The NBO analysis lists out the highest and lowest interaction of hyperconjugative energy. The docking analysis reveals the interaction of metformin cation with the amino acid residues present in the 1FM9 protein. References [1] D.Stepensky, M.Friedman, W.Srour, I.Raz, & A.Hoffman, J.Contr.Rel, 2001. 71, 107–115. DOI: 10.1016/S0168-3659(00)00374-6. [2] E.Selvin, S.Bolen, H.C.Yeh, C.Wiley, L.M.Wilson, S.S.Marinopoulos, L.Feldman, J.Vassy, R.Wilson, E.B.Bass & F.L.Brancati, (2008).Arch. Intern. Med.27, 168, ISSN:0003-9926. [3] Gaussian 09, Revision A.01, Gaussian, Inc., Wallingford CT, 2010. [4] R.S. Mulliken J. Chem. Phys. 23 (1955) 1833, DOI: 10.1063/1.1740588 [5] R W F. Bader, Atoms in molecules a quantum theory, Oxford Science Publications (London: Clarendon), 1994. ISBN: 9780198558651.

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[6] A. E. Reed and F.Weinhold, J. Chem. Phys. F8 (1983) 4066. DOI: 10.1063/1.445134 [7] T. Koopmans, Physica, 1, (1933) 104. DOI:10.1016/S0031-8914(34)90011-2 [8] G.Schüürmann, Quantum chemical descriptors in structure-activity relationships – calculation, interpretation and comparison of methods. In Predicting Chemical Toxicity and Fate, 2004, DOI: 10.1201/9780203642627.ch6 [9] J.P.Perdew, R.G.Parr, M. Levy and J.L.Balduz 1982 Phys. Rev. Lett. 49 1691. DOI.org/10.1103/PhysRevLett.49.1691. [10] P.Geerlings, F.De Proft, W. Langenaeker, Conceptual density functional theory. Chem. Rev. 2003, 103, 1793-1873. DOI: 10.1021/cr990029p. [11] R.G. Parr, R.G. Pearson, J. Am. Chem. Soc., 105 (1983) 7512. DOI: 10.1021/ja00364a005. [12] P.Senet, Chem. Phys. Lett., 275 (1997) 527-532. DOI:10.1016/S0009-2614(97)00799-9. [13] RG.Parr, L.Szentpaly and S.Liu, J.Am.Chem.Soc., 121 (1999) 1922-1924. DOI: 10.1021/ja983494x. [14] N. Okulik, A. H. Jubert, DOI:10.1016/j.theochem.2004.04.069.

Mol.

Struct.

THEOCHEM

682

(2004)

55.

[15] R.Zhou, L.X. Hong and Z.X. Zhou, Ind. J. of Pure and Applied Physics, 50(2012) 719-726 ISSN: 0975-1041 (Online); 0019-5596 (Print). Cite the paper R. Niranjana Devi, S. Israel, C. Ancline, (2017). An Analysis of Structural, Electronic and Reactivity Properties of MetforminChloride using XRD and DFT Approach. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.19.50.462

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Structural, Spectroscopic, Thermal studies of Pure and DL-Methionine Doped ADP Crystals3 J.H. Joshi1, H.O. Jethva1, P.T. Bagda1, K. Ashish Prasad1, M.J. Joshi1 1 – Department of Physics, Saurashtra University, Rajkot – 360 005, India DOI 10.2412/mmse.42.48.140 provided by Seo4U.link

Keywords: ammonium dihydrogen phosphate, powder XRD, FT-IR, TGA/DTA.

ABSTRACT. The growth of Nonlinear Optical crystals retains great number of attention nowadays. Ammonium Dihydrogen Phosphate (ADP) is an important NLO material used for electro-optical applications and LASER material for Nd: YAG and Nd: YLF etc. Amino acids due to their properties like molecular chirality and zwitter ionic structure attract many researchers to dope them in ADP for the improvement of its properties. The Pure and 0.1wt% DL-Methionine doped ADP crystals were grown using slow solvent evaporation technique at room temperature. The Powder XRD shows single phase nature of doped crystal with slight variation in unit cell parameters. The interaction of DL-Methionine with functional groups of ADP crystal was studied using FT-IR spectroscopy. The TGA curve of pure ADP sample indicates that it remain stable upto 200 oC and then decompose slowly, while the doped sample slowly decomposes right from beginning of the analysis. The DTA curves exhibits endothermic peaks at 209 oC and 212 oC for pure and doped sample, respectively.

Introduction. Ammonium dihydrogen phosphate (ADP) is important isomorphs of the Potassium dihydrogen phosphate (KDP) type crystal, which is used for several nonlinear optical applications and higher SHG efficiency of fundamental laser with large NLO coefficients [1-2]. Amino acids possess properties like molecular chirality, absence of strongly conjugated bond and Zwitter ionic nature [3] attracted researcher to dope them in KDP [4] and ADP [5,6] crystals to improve the NLO performance and other properties. DL-Methionine consists of a 4-carbon aliphatic straight chain, the distal end of which is capped by a complex guanidinium group. The conjugation between the double bond and the nitrogen lone pairs, the positive charge is de-localized, enabling the formation of multiple H-bonds. In present context, the authors have doped amino acid DL-Methionine in ADP crystals to investigate its effect on structural, spectroscopic and thermal properties. Experimental Technique. The slow solvent evaporation technique was employed for the growth of crystals. ADP was added to 200ml distilled water under constant stirring to achieve saturation. After rigorous stirring for 4 hours the solution was filtered using Watmann filter paper no.1. Then the solution was subdivided into two beakers; one beaker contains 100ml pure ADP solution and in the other beaker 0.1wt% DL-Methionine was added in 100 ml solution of ADP and stirred well for 4 hours. All beakers were kept in a dust free atmosphere with a porous lid to control the evaporation. After 20 days good quality, transparent, colourless crystals were harvested. Fig. 1show the harvested crystals of pure ADP and 0.1wt %DL-Methionine doped ADP, respectively.

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Pure ADP

DL-Methionine doped ADP

Fig. 1. Grown crystal of Pure and 0.1wt% DL-Methionine doped ADP crystals. Powder XRD was carried on PHILIPS X’PERT MPD system and the data were analyzed by software powder-X. FTIR spectra were recorded in KBr media within the region of 400–4000 cm-1 employing THERMO NICOLET 6700 spectrophotometer. The TGA/DTA/ was performed on Linseis STA PT 1600 setup from room temperature to 9000C at a heating rate of 150C/min in air atmosphere. Results and Discussion:

Fig. 2. Powder XRD Pattern. Fig. 2 shows Powder XRD pattern of pure and 0.1wt% DL-Methionine doped ADP crystals. From the Fig. it can be seen that due to doping of DL-Methionine in ADP no additional phase was observed and both the samples retained single phase nature with characteristic diffraction peaks like (2 0 0), (1 1 2), (2 0 2), (3 0 1), (3 0 3), (2 0 4), (3 2 3) etc. But the variation in intensity is observed which indicates the presence of dopant in ADP. Both the crystals belonged to tetragonal symmetry with lattice parameter a=b=7.504 Å, c=7.552 Å for pure ADP and a=b=7.507 Å, c=7.557 Å for 0.1wt% DL-Methionine doped ADP. To estimate the lattice strain introduced by the dopin, the Williamson-Hall method was applied to power XRD patters [7]. β cosθ = Kλ/L + ηsinθ where β – full width half maximum of high internsity diffraction peaks; L – crystallite size; MMSE Journal. Open Access www.mmse.xyz

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η – strain; K – 0.9; λ – 1.54178 Å.

Fig. 3. (a-b).W-H plots of pure and 0.1wt% DL-Methionine doped ADP crystals. Fig. 3(a-b) shows Williamson – Hall plots of pure and 0.1wt% DL-Methionine doped ADP crystals respectively. The linear fitted plot of βcosθ vesus sinθ gives crystallite size and strain from intercept and slope respectively. The crystallite size is found to be 0.431 mm and 0.779 mm while the strain is found to be 0.03161 and 0.00515 for pure and 0.1wt% DL-Methionine doped ADP crystals respectively. Such plots revel that the doping of DL-Methionine in ADP increses teh crystallite size of ADP and decrese the lattice strain. These results confirmed presence of DL-Methionine in ADP.

Fig. 4. FT-IR spectra of pure and 0.1wt% DL-Methionine doped ADP crystals. The doping of DL-Methionine in ADP was confirmed by FT-IR spectra of Fig. 4. The FT-IR spectrum of pure ADP crystal shows the O-H stretching of water at 3229 cm-1, P-O-H stretching at 1084 cm-1, N-H stretching of ammonium at 2825 cm-1 and PO4 vibration at 590 cm-1 and 453 cm-1. The FT-IR spectrum DL-Methionine doped ADP shows the peak shifting from higher to lower wavelength due MMSE Journal. Open Access www.mmse.xyz

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to presence of DL-Methionine in ADP, e.g., the PO4 vibration of pure ADP is shifted from 590 cm-1 to 565 cm-1 in the doped ADP crystal. The FTIR spectrum of DL-Methionine doped ADP indicates absorption occurring at 2828 cm-1 and 1697 cm-1 are due to C-H symmetric stretching and C=O stretching of COOH group, respectively, indicating the presence of amino acid, which is absent in pure ADP. The relation between the absorption frequency and the force constant can be written as [8], υ = 1330 [F (1/M1 + 1/M2)] ½ where υ – absorption frequency (cm-1), 1330 = (NA10)1/2/ 2C; NA – Avogadro’s number; F – force constant (Nm-1); M1 and M2 – molecular masses of atoms (u). Presently the force constant for O-H stretching vibration were calculated. It is found to be 558 N/m and 552 N/m for pure and 0.1wt% DL-Methionine doped ADP respectively. It can be seen that the force constant altered as the DL-Methionine interacts with the hydrogen bond of ADP.

Fig. 5. (a-b) TGA/DTA curves for pure and 0.1wt% DL-Methionine doped ADP crystals. Figures 5 (a-b) shows the TGA/DTA curves of pure and 0.1wt% DL-methionine doped ADP crystals, respectively. The pure ADP sample destabilizes above 200oC and starts decomposing and above 500oC it is decomposed more than 69% of the original mass by expelling various gases. From the thermogram of 0.1 weight % DL-methionine doped ADP crystal, it is found that the crystal starts decomposing very slowly right from the beginning of the analysis and at 200 oC it is decomposed by 6 % of the original weight, thereafter, the thermal behaviour is almost the same that of the pure ADP. The endothermic reaction peak can be assigned due to melting and decomposition of ADP, i.e. decomposition to orthophosphoric acid H3PO4 of the crystal [9]. It can be found that the stability of the crystals is not appreciably affected by doping of amino acid DL-methionine in ADP.

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Table 1. Thermodynamic parameters of pure and 0.1wt% DL-Methionine doped ADP crystals. Sample

Reaction

Peak

ΔH

ΔCp

Temperature

(J/kg)

(J/kg.K)

Amount of Heat change (Vs/kg)

(0C) Pure ADP

Endothermic

2090

-45.56 * 10-4

648

-160.26

ADP + 0.1wt% DLM

Endothermic

2120

-50.75 * 10-4

1351

-160.38

Summary. The pure and 0.1wt% DL-Methionine doped ADP crystals were successfully grown by slow solvent evaporation technique at room temperature. The powder XRD exhibits single phase nature of doped sample with slight variation in the unit cell parameters. The shifting of absorption peaks in FT-IR and the occurrence of absorptions responsible to C-H and C=O indicated interaction of amino acids with ADP. The Thermal study shows DL-methionine marginally reduced the thermal stability of ADP. Acknowledgement. The authors are thankful to UGC for financial assistance under SAP DRS – II and DST under FIST and Prof. H.H.Joshi (Head, Department of Physics, Saurashtra University, Rajkot) for his encouragement and support References [1] R.B.Adhav, Application of Nonlinear Crystals in LIA Handbook of Laser Material Processing, Mognolia (2001). [2] D.N.Nikogosyan, Nonlinear Optical Crystals A Complete Survey, Springer Heidelberg (2005). [3] J.F.Nicoud, R.J.Twieg, Eds, D.S.Chemla and J.Zyss, Academic press, London, 277 (1987). [4] K.D.Parikh, D.J.Dave, B.B.Parekh and M.J.Joshi, Bull.Mater.Scie, 30,105-112 (2007). doi:10.1007/s12034-007-0019-4. [5] J.H.Joshi, B.V.Jogiya, M.J.Joshi and K.D.Parikh, Int. J. Chemtch. Res.,6, 1555-1558 (2014). [6] T.Josephine Rani, F.Loretta, P.Selvarajan, S.Ramalingom, S.Peruma, Rec.Res.Scie & Tech.,3(7),69-72,2011. [7] G.K.Williamson, W.H.Hall, X-ray line broadening from filed aluminium and wolfram, 1(1)(1953)22-31 doi:10.1016/0001-6161(53)90006-6. [8] V.S.Joshi, M.J.Joshi, Ind.J.Phy., 75(2) (2001) 159-163. [9] A.Abdul Kadar, A.A.Ammer, doi:10.1016/0040-6031(91)80285-Q.

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176(1991)293-304.

Cite the paper J.H. Joshi, H.O. Jethva, P.T. Bagda, K. Ashish Prasad, M.J. Joshi, (2017). Structural, Spectroscopic, Thermal studies of Pure and DL-Methionine Doped ADP Crystals. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.42.48.140

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Impedance Spectroscopy of Sodium Sulphide Added ADP Crystals 4 A.P. Kochuparampil1, J.H. Joshi1, H.O. Jethva1, M.J. Joshi1 1 – Department of Physics, Saurashtra University, Rajkot, Gujarat, India DOI 10.2412/mmse.4.87.814 provided by Seo4U.link

Keywords: slow solvent evaporation, ADP, Chalcogenide, dielectric, complex impedance, complex modulus.

ABSTRACT. Ammonium dihydrogen phosphate (ADP) is popular nonlinear optical material with wide applications. Chalcogenide compounds are very poorly soluble in water and hence difficult to add during growth of ADP from aqueous solution to engineer and modify properties of ADP. Hence the solubility of chalcogenide compound Na2S was increased by synthesizing its nano-particles with capping agents. The growth of pure and Na2S added crystal was achieved by the slow solvent evaporation method. Complex impedance plots were recorded in the frequency range of 100 Hz to 1MHz at room temperature. Dielectric constant and loss exhibited normal behaviour with respect to frequency. The complex modulus spectra indicated effect of grain and grain boundary in pure ADP sample. From Jonscher’s plot various parameters were calculated and found to decrease for doped samples compared to pure ADP. The non Debye type relaxation was found from plots of Z'' and M'' versus frequency.

Introduction. Complex Impedance Spectroscopy is an effective experimental technique used to characterize a.c. electrical properties of crystalline materials. It enables to resolve the relaxation contributions, like, bulk effects, grain boundaries and electrode interface effects in the frequency domain of materials [1]. Ammonium Dihydrogen Phosphate (ADP) is widely used in the area of nonlinear optics, electric-optics, harmonic generation and optical mixing [2]. Na2S can be used as thermo-chemical storage system [3]. In present paper authors studied dielectric, complex impedance and modulus spectroscopic aspects of pure and Na2S doped ADP crystals. The authors aim is to add Na2S in ADP crystal to engineer and modify its properties. Experimental: Sodium sulphide (Na2S) was synthesised by co-precipitation method and then sample was irradiated through microwave to increase the solubility of precipitate nanoparticles. 0.5M sodium acetate (CH3COONa) and 1.5M thiourea (CH4N2S) were taken as starting materials. The solution of sodium acetate was filled in burette. 10ml capping agent ethylene diammine was added in the thiourea solution at 700C. The solution of sodium acetate was added in drop-wise manner into the thiourea solution, resulting towards light yellowish precipitate. After continuous stirring of 7 hours the colloidal solution was subjected to the microwave irradiation in domestic microwave oven of Kenstar having input power of 1450W and by adjusting microwave irradiation 10% of input power, 145W for 15 minutes till that the solution completely evaporated and only solid remained which was further washed by distilled water and acetone. The dried irradiated sample was crushed using mortar pestle. As the chalcogenide compound Na2S nanoparticles were very less soluble in water to increase its solubility capping agent ethylene diammine was used. Its solubility was increased and found to be 0.18g in 100ml. Pure ADP and Na2S added ADP crystals were grown by using the slow solvent evaporation method at room temperature. Required amount of ADP was added to 400ml distilled water under constant stirring to achieve saturation. After rigorous stirring for 4 hours the solution was filtered using Watmann filter paper no.1. Then the solution was subdivided into four beakers; one beaker contains 100ml pure ADP solution and in the other three for 2ml, 5ml and 10ml Na 2S solution was added in ADP solution and stirred for 3 hours. After 15 days the highly transparent and good © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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quality crystals have been grown, due to the doping of Na 2S in ADP crystal there was no colour change, but the change in morphology indicates the presence of dopants in ADP crystals as shown in Fig. 1.

Fig. 1. a) pure ADP, b) 2NADP, c) 5NADP and d) 10NADP. The AAS was carried on Shimazdu AA-6200 with sodium source was used to detect sodium in doped crystals and the results were listed in table 1.The complex impedance spectra were recorded for pelletized samples in a frequency range of 10Hz to 10MHz at room temperature using HIOKI 3532 LCR HITERSTER meter. Result and discussion

Fig. 2. a) Dielectric constant versus logω and b) Dielectric loss versus logω. Fig. 2 a) shows variations of dielectric constant with respect to applied angular frequency for pure and different mole percentage Na2S added ADP crystals. High dielectric constant at lower frequency for all samples which may due to the contribution of all kinds of polarization, Viz., electronic, ionic, orientation and space charge polarizations. As frequency increases the dielectric constant decreases because the dipoles can not comply with the variation of the external field and hence the polarization decreases. The doped samples possessed low dielectric constant compared to pure. Fig.2 b) shows variation in dielectric loss with respect to the angular frequency. From the Fig. it can be seen that the MMSE Journal. Open Access www.mmse.xyz

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doped sample exhibits less dielectric loss compared to pure ADP, which indicates that the doped samples possessed minimum defect and good optical properties [4].

Fig. 3. Jonscher’s Plot. Fig.3 shows Jonscher’s plot of both pure and Na2S added ADP crystals. Jonscher’s power law is: σtot= σdc + Aωn where A is dependent on temperature and indicates the strength of polarizibility and exponent n – is the degree of interaction of mobile ions with lattice. The a.c. conductivity value is lower for all Na2S added ADP crystals as compared to pure ADP. The a.c. conductivity decreases slightly with increases the doping concentration. The main reason for conduction is due to L-defect in intra-bond jump of proton generates the vacancy and D-defect at inter-bond jump to a double occupied bond [5]. The electric conduction in ADP is ionic and the migrating charge carrier is proton, which moves in the three-dimensional hydrogen bond network, affecting the motion of neighbouring protons. To occupy the Na2S molecule in site it creates a defect. As the conduction in ADP is protonic and mainly due to the anion [(H 2PO4)- ion] and not due to the cation [(NH4)+ ion], the additional hydrogen bonds created may reduce the L-defect and as a result obstruct the movement of protons. This may be the reason for the decrease in a.c. conductivity value in all Na2S added ADP crystals. Here the higher value of ‘n’ for pure ADP indicates large energy stored in such collective motion [6].The values of ‘A’ and ‘n’ are listed in table 1.

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Fig. 4. Nyquist plot a) Pure ADP and b) Na2S added ADP. Fig.4. shows Nyquist plots of pure ADP and Na2S added ADP crystal. The small semi-circle near the origin for pure ADP at higher frequency region indicates the grain effect and the large semi-circle at lower frequency indicates the grain boundary effect, while same plots for the Na2S added ADP samples shows single semi-circle indicates grain effect only. The equivalent R-C parallel circuits are presented at inset of fig. 4.

Fig. 5. Complex modulus. To discriminate the electrode polarization and grain boundary effect complex electric modulus is used. Fig. 5 shows complex modulus plots for pure and Na2S added ADP. In pure ADP spectrum two clear semi circles appear due to grain at higher frequency and grain boundary effect at lower frequency, while for doped ADP crystals, single semicircles are observed confirming the presence of grain effect only.

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Fig. 6. M’’ and Z’’ versus logω a)Pure ADP, b) 2NADP, c) 5NADP and d) 10NADP. Fig.6 shows the plots of M'' and Z'' versus applied angular frequency. The modulus spectra of pure and Na2S added ADP crystals, exhibit broad and asymmetric nature indicating non-Debye type relaxation process with distributed relaxation times about mean relaxation time. The non-Debye type relaxation immediately indicates the stretched exponent parameter β, given as β = 1.196/W - 0.047, where W is FWHM from M'' Vs logω plot. The smaller the value of β the greater is the deviation with respect to Debye type relaxation. The β value is always less than unity for a system in which the dipole-dipole interaction is significant [7]. From table no.1 it can be seen that the β parameter of doped samples appropches to higher value compare with pure ADP indicates more debye type relaxation behaviour in doped samples compare to pure. Table 1. AAS data and parameters of complex impedance and complex modulus.

Sample

ppm Rg counts of (MΩ) Na+

τgb

Rgb

Cgb

(pF)

(MΩ)

(pF)

(mS) (mS)

141.5

30.75

58.47

4.08

Pure ADP

2NADP

0.89

66.97 43.07

5NADP

1.98

98.28 18.44

10NADP

3.66

48.83 38.32

28.9

τg

A (S.m-1.rad-n)

0.71

8.26x10-6

0.145

2.88

0.51

1.58x10-8

0.517

1.81

0.50

1.62x10-8

0.520

1.87

0.47

2.51x10-8

0.4990

1.79

Summary. Pure and Na2S added ADP crystals have been sucessfully grown using slow solvent evaporation method. The AAS data confirms the presence of sodium ion in Na2S added ADP crystals. MMSE Journal. Open Access www.mmse.xyz

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Dielectric constant and dielectric loss found to be lower in Na2S added ADP compared to pure ADP. The Jonscher’s Plot is applied to the a.c. conductivity. The complex modulus spectra showing two semi-circle for pureADP due to presence of grain and grain boundary and single semi circle for Na2S added ADP due to effect of grain only. The streched exponent revels more debye type relaxation in doped samples compare to pure one. The Impedance and Modulus spectroscopy found to be very sensitive for small concentration of dopant in ADP. Acknowledgement. Authors are thankful to Prof. H.H. Joshi (HOD, Department of Physics, Saurashtra University, Rajkot, Gujarat, India) ,Prof. D.K. Kanchan (M.S. University, Baroda, Gujarat, India) for their keen interest and also the authors acknowledge the financial assistance under SAP DRS-II and DST FIST. References [1] J.R.Macdonald, Impedance Spectroscopy, (John Wiley and Sons, 1987) [2] D.N. Nikogosyan, Nonlinear Optical Crystals, A complete Survey, Spinger, Heidelberg (2005) [3] M. Roelands, R. Cuypers, K. D. Kruit, H. Oversloot, A. Jong, W. Duvalois, L. Vliet and C. Hoegaerts, Energy Procedia 70 ( 2015 ) 257 – 266. [4] D.Zion, S.Devarajan, T.Arunachalam, Journal of Crystallization Process & Technology, 3 (2013) 5-11. doi:10.4236/jcpt.2013.31002. [5] M.Meena and C.K.Mahadevan, Crystal Research and Technology, 43(2) (2008) 166 – 172, doi:10.1002/crat.200711064. [6] J.H. Joshi, K.P.Dixit, M.J.Joshi and K.D. Parikh, AIP conference Proceeding, Bikaner, 2016, (2016) pp.1728–1731, doi: 10.1063/1.4946270. [7] M.P.Dasari, K.S.Rao, P.M.Krishna, G.Gopala Krishnan, Acta Physica Polonica A, 119(3) (2011) 387-394. Cite the paper A.P. Kochuparampil, J.H. Joshi, H.O. Jethva and M.J. Joshi, (2017). Impedance Spectroscopy of Sodium Sulphide Added ADP Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.4.87.814

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Growth and Characterization of a Novel Nonlinear Optical Single Crystal of LIsoleucinium Hydrogen Maleate Hemihydrate 5 A. Hemalatha1,2, K. Deepa3, A. Venkatesan4, S. Senthil2, a 1 – Department of Physics, Quaid-E-Millath Government College for women, Chennai, India 2 – Department of Physics, Government Arts College (Men), Nandanam, Chennai, India 3 – Department of Physics, Loyola College, Chennai, India 4 – Department of Physics, Aringnar Anna Government Arts College, Villuppuram, India a – ssatoms@yahoo.co.in DOI 10.2412/mmse.85.63.511 provided by Seo4U.link

Keywords: nonlinear optical single crystal, monoclinic system, XRD analysis, NIR spectroscopy.

Abstract: L– Isoleucinium Hydrogen Maleate Hemihydrate (LIM), a nonlinear optical single crystal was grown from aqueous medium by the slow evaporation method at room temperature. The powder XRD analysis reveals that the grown crystal is belongs to monoclinic system with the space group P2 1. The presence of various functional groups in the LIM is confirmed by FT-IR and FT-RAMAN spectroscopy. The second harmonic generation (SHG) efficiency measurements reveal that the LIM is suitable for nonlinear optical (NLO) applications. Thermo-gravimetric and differential thermo gravimetric analysis reveal the thermal stability of the material. The optical transparency has been studied using UV-VisNIR spectroscopy and the band gap energy were found out from the absorption studies. The third order nonlinear behavior has been investigated using Z-Scan technique.

Intorduction. L- Isoleucine is organic amino acid which is the potential material with excellent optical, thermal and mechanical properties. It is non-polar and aliphatic in nature. L-Isoluecine have been studied and reported in the literature[1]. L-Malic acid is a organic component and it is basically dicarboxilic acid with large π-conjucation has attracted much attention [2]. In the present work LIsoluecinium hydrogen maleate hemihydrates was grown from aqueous solution by slow evaporation method. The material was characterised by powder XRD analysis, UV-Vis-NIR spectroscopic studies, FT-IR and FT-RAMAN studies, TGA/DTA analysis and Nonlinear optical Studies were discussed. Crystal growth. LIM crystal was synthesized from L-Isoluecine and L-Maleic acid taken in equimolar ratio. The required quantity of L-Isoleucine and L-Maleic acid was thoroughly dissolved in 2D water and stired well for about six hours using a magnetic stirrer to obtain a homogenoes mixture. Then the saturated solution of LIM was taken in a beaker and kept at room temperature for crystallisation. Finnaly a well defined single crystal was obtained after 40 days by slow evaporation method. CHARACTERIZATION Powder x-ray analysis. Powder x-ray differaction technique is used to show the inner arrangements of atoms molecules in a crystalline material. The XRD study enumerates that the LIM belong to the monoclinic crystal system with space group P21 and the lattice parameters are a=11.745 (Å),

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b=6.1011(Å),c=19.2198(Å), α= γ=90°, β=96.7329°. Further the diffraction pattern (Fig.1) of LIM is perfectly matched with the reported literature [1,3].

Fig. 1. Powder XRD pattern of the LIM crystals. Optical Analysis. Absorption spectroscopy is one of the best techniques to check the suitablity of the grown crystal for optical device fabrication. The absorption spectrum of the grown LIM single crystal is as shown in fig. 2(a). The crystals are transparent in the entire tested region with lower cut off waveslength at 215nm. The highly tranparent is the essential requirment for optically active materials. The recorded optical data was used to calculate the band gap of the grown crystal. The band gap of the LIM crystal is shown in fig. 2(b) and found to be 4.75 eV. The grown LIM crystal can be a suitable candidate for optoelectronic applications because of its large band gap [4].

Absorption(A) (%)

3.0

(a)

215

LIM

2.5

2.0

1.5

1.0 250

300

350

400

450

500

550

600

650

700

wavelength)nm

Fig. 2. (a). UV-Vis absorption spectrum of LIM.

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LIM

(b)

8 6



h x10 (eV) m

4 2 4.75eV

0 0

heV

Fig. 2. (b). plot of (αhν)2 versus hν of LIM crystal. NLO Studies. In NLO material Second hormonic generation efficiency is most important [5]. A Qswitched Nd: YAG laser emitting a fundamental wavelength of 1064 nm and a pulse width of 9 ns with a repetetion rate of 10 Hz was used. The laser incident input energy of 0.7 mJ/s was illuminate on the crystalline powder, which is filled in an air tight micro capilary tube. The emission of green radiation of wavelength 532nm from the sample confirmed the frequency doubling of LIM. The KDP was used as a reference material and the output energy was found to be 4.48 mW and 5.03mW from grown crystal and reference materials respectively. Hence, from the above discussion second hormonic generation efficincy of LIM crystal was 0.9 times that of standard KDP crystal. Thus LIM is confirmed as a suitable NLO medium for laser generation. Third Hormonic Generation. Third order NLO studies of LIM crystals were performed by a versatile tool of Z scan technique. It is a acurate method to determine the nonlinear index of refraction (n2), nonlinear absorption coefficient (β) and nonlinear susceptability ((3)) of the grown crystal. In this technique a He-Ne laser (=632.8nm) is used as the light source and is by a lens of focal length 18.5cm. The open aperture mode helps us to calculate the nonlinear absorption coefficient and the closed aperture mode shows the information about the third order nonlinear refractive index and the open and closed aperture modes are shown in fig.4 (a) andfig.4 (b). The nonlinear refractive index (n2), the nonlinear absorption coefficient (β) and the third order nonlinear optical susceptibility ((3)) are calculated and are given in table 1.

14.0

Normalized Transmittance

(a)

LIM

13.5

13.0

12.5

12.0 -2

8 10 12 14 16 18 20 22 24 26

Z (mm)

Fig. 3. (a)Closed aperture z-scan spectrum of LIM crystal. MMSE Journal. Open Access www.mmse.xyz

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Normalized Transmittance ( a.u.)

15.2

LIM

(b)

15.0 14.8 14.6 14.4 14.2 14.0 13.8 13.6 13.4 13.2 13.0 3

Z (mm)

Fig. 3. (b) open aperture z-scan spectrum of LIM crystal. Table 1. Parameters in Z scan experiment. 2.458x10-11 cm2/W

Nonlinear refractive index (n2) Nonlinear absorption coefficient (β)

2.438x10-5 cm/W

Third order nonlinear susceptibility ((3))

5.5236x 10-5 esu

Thermal Analysis. The thermal stability of LIM was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) at a temperature range from room temprature to 650°C and the thermogram is shown in fig.4. The TGA and DTA analysis is very important to understand the thermal stability and various transaction of the sample. From TG curve, it has one stage of weight loss. The compound start to decomposs at 144°C. The weight loss of approximately 82% occures between the temperature 144°C - 570°C due to the elimination of a molecule such as CO2, H and O and major weight loss due to decomposition of the crystal. The remaining weight loss occurs above 570°C and the sample is completely decomposed. DTA curve shows two endothermic peaks and three exothermic peaks at 87.6°C, 128°C, 144°C, 489.6°C and 540°C respectively. The sharp peak indicating the purity and crystallinity of the material. The endothermic peak observed at 87°C shows the weight loss is about 7% due to the liberation of water molecules present in the crystal itself. The first exothermic peak absorved at 144°C. It is equal to the decomposition point of the TGA curve. The second exothermic peak observed at 489.6°C which is matched with the TGA curve. From the DTA and TGA study, it is observed that the material has water molecules in its crystal lattice and it has thermal stability till its 144°C. Vibrational spectral Analysis. FTIR and FT Raman spectroscopy are very important to analysis the various functional groups in the structure of a compound present in the grown crystal and are shown in fig.5(a) and fig. 5(b). In the high energy region there is a broad band observed from 3600 cm -12400 cm-1 is assigned for O-H stretching vibration of carboxlic group.It is also over lap with the peaks corresponding to NH assymetric stretching vibration due to the primary amines of NH 2 at 3346 cm1. CH3 assymetric stretching vibration modes at2964 cm-1. The peaks at 2946 cm-1 is due to NH3 assymetric stretching vibration which is also over lap on the OH stretching vibration and the corresponding band in the Raman spectrum is observed at 2942 cm-1. Strong band observed at 1739 cm-1 contributed of C=O symetric vibration of –COOH group. The peak at 1578 cm-1 is due to the NH3 deformation. The bands appeared in the region 1472 cm-1 and 1395 cm-1 are assigned to COO-1 symmetric stretching vibration of –COOH group and the corresponding band is observed at 1453 cm1 in the Raman spectrum. The peaks at 1347 cm-1 and 1004 cm-1 occurs due to the CN vibration and the corresponding band is observed at 1005 cm-1 in the Raman spectrum. The peak observed at 1308 cm-1 is due to CH2 wagging vibration and the corresponding peak is also observed at 1302 cm-1 in the MMSE Journal. Open Access www.mmse.xyz

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Raman spectrum. The NH3 rocking vibration observed at 1174 cm-1. C-CN symetric stretching vibtation observed at 926 cm-1. Very strong band observed at 871 cm-1 due to the C-C stretching vibration. The COO-1wagging and rocking vibrations are observed at 578 cm-1 and 483 cm-1 respectively and the corresponding band are observed at 540 cm-1 and 479 cm-1 in the Raman spectrum. The vibrational study confirms the presence of COOH and NH 2 group in the LIM crystal. TGA

144°C

LIM

489.3°C

6000

100

5000

540°C

4000

3000 2000

DTA

TG%

DTA%/min

7000

1000 570°C

87.6°C 128°C 144°C -50 0

100

200

300

400

500

600

700

TEMP (°C)

Fig. 4. TG/DTA curve for LIM crystal.

(b) LIM

LIM

2964

0 4000

3500

3000

2500

2000

1500

1000

1398

0.0 500

3000

1694 1619

2500

2000

1500

1000

299

166

808 742

0.1

540 479 431

926 1739 1174 871 1249 713 1578 147213471004

1005 910

1211

578

1395

1302

1308

2646

0.2

1453

1211

1891

2744

3515 3346

2982 2942 2913

0.3

2878

483

3055

RAMAN INTENSITY

(a)

100

0.4

500

Wave Numbers cm-1

Fig. 5. (a) FT-IR spectrum of the grown LIM crystal, (b)FT-RAMAN of the grown LIM crystal Summary. Single crystals of LIM were grown by slow evaporation solution growth method at room temperature. Powder x-ray diffraction analysis was carried out and the lattice parameters were calculated. The Calculated values are good in agreement with the reported values. UV-Vis-NIR study shows that the crystals are transperant in entire visible region and have minimum cut off wavelength of 215nm. Thermal analysis was carried out and it confirms the crystal is stable upto 144°C. Its Second Harmonic Generation efficiency was found to be 0.9 times that of standard KDP. The functional groups present in the LIM crystal is identified by FTIR analysis and it is confirmed by the FT-RAMAN. The nonlinear optical refractive index is (n2) 2.458x10-11 cm2/W, nonlinear absorption coefficient (β) is 2.438x10 -5 cm/W and third order nonlinear optical susceptibility ((3)) of 5.5236x 10-5 esu are calculated by Z scan technique. Hence LIM single crystals are suitable material for nonlinear optical device fabrication. References [1] Sergey G. Arkhipov, Denis A. Rychkov, Alexey M. Pugachevc and Elena V.Boldyrevaa , Structural Chemistry (Research Paper), New hydrophobic L-amino acid salts: maleates of L-leucine, L-isoleucine and L-norvaline, Journal of Acta Crystal C, 2015, C17, 1-9. DOI. org/10.1107/S2053229615010888. MMSE Journal. Open Access www.mmse.xyz

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[2] C. Alosious Gonsago, Helen Merina Albert, S. Janarthanan, and A. Joseph Arul Pragasam, Crystal Growth and Characterization of an Organic Nonlinear Optical Material: L-Histidinium Maleate,(LHM), International Journal of Applied Physics and Mathematics, November 2012,Vol.2, No. 6, DOI: 10.7763/IJAPM.2012.V2.150 [3] G. Ramasamy, Subbiah, Meenakshisundaram, Studies on amino acid picrates: Crystal growth, structure and characterization of a new nonlinear optical material l-isoleucinium picrate, Journal of optic communication, 2014, 125, 4422-4426. DOI. org /10.1016/j.ijleo.2014.02.036 [4] Mohd Shkir, Haider Abbas, Physico chemical properties of L-asparagine L-tartaric acid single crystals: A new nonlinear optical material, Journal of Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, (2014), 118, 172â&#x20AC;&#x201C;176, DOI. org / 10.1016/j.saa.2013.08.086. [5] S. Masilamani, A. Mohamed Musthafa, P. Krishnamurthi, Synthesis, Growth and characterisation of a semiorganic nonlinear optical material: L-threonine cadmium chloride single crystals, Arabian Journal of Chemistry, 2014, DOI.org/10.1016/j.arabjc.2014.06.003. Cite the paper A. Hemalatha, K. Deepa, A. Venkatesan, S. Senthil (2017). Growth and Characterization of a Novel Nonlinear Optical Single Crystal of l-Isoleucinium Hydrogen Maleate Hemihydrate. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.85.63.511

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Group 12-Metal Complexes derived from Donor Substituted Carboxylic Acids and 5-Nitro-1,10-Phenanthroline: Spectroscopic and Biological Studies 6 Champaka Gurudevaru1, Nallasamy Palanisami1 1 – Department of Chemistry, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu, India DOI 10.2412/mmse.46.5.782 provided by Seo4U.link

Keywords: metal complexes, 5-Nitro-1,10-phenanthroline, Donor Carboxylic acid, Anti-fungal and Anti-Microbial studies.

ABSTRACT. Momeric group 12 metal complexes [M(R-C6H4-COO)2(5-NO2-phen)] [M=Zn, R=NMe2 (1) and M=Cd, R=NH2 (2)] have been synthesized from a reaction between the metal acetate, donor substituted carboxylic acid and 5nitro-1,10-phenathroline (5-NO2-Phen) at room temperature. Both complexes were characterized by elemental analysis, FT-IR spectroscopy, 1H NMR and UV-Vis spectroscopy studies. Compound 1 showed more potent anti-fungal activity when compared to standard drug fluconazole and demonstrated MIC at concentration 1.6 µg/ml, 25 µg/ml, 0.4 µg/ml, 3.12 µg/ml against K. pneumonia, Pseudomonas, S. aureus, S. mutans respectively.

Introduction. In the past three decades, transition metal (TM) complexes research has been found applications in the fields like catalysis, material science and biology [1-3]. In particular, group 12 complexes with chelating ligands show interesting biological activity, since zinc plays an importance role in many biological processes[4-6].The synthesis of derivatives of 1,10-phenanthroline and investigations of their properties have become an attractive research area [9]. Furthermore, carboxylate group can bind with metal ion in various modes, such as monodentate, bidentate and bridging which are good source of ligands (O-donor) for the very generous strong bonds that they form [10-12]. The metal complexes based on 5-nitro-1,10-phenanthroline carboxylates and further exploiting the relationship between their structure and biological properties have constituted one of the most attractive research fields in modern bioinorganic chemistry [13]. In particular, the zinc complexes of different substituted carboxylic acids are important substances which have been found to be useful as antimicrobial and antifungal agents and the antimicrobial and antifungal mode of action of these molecules is still not fully understood while the few groups attempted to understand the mechanism of antibacterial and antifungal activity of zinc compounds were done, but still it is unclear [14-15]. The best of our knowledge, there is no report in the literature on antibacterial and antifungal studies based on zinc derivative of aromaticcarboxylates using 5-nitro-1,10-phenanthroline as a co-ligand. Inspired by the aforementioned considerations, we report here,the synthesis and investigation of synthesis, spectral and antimicrobial and antifungal activity of group 12 metal complexes with 5-nitro 1,10-phenanthroline as a co-ligand. Experimental Instruments and Methods. Elemental analysis (C, H and N) was performed using LECO-932 CHNS Analyser, IR spectra was recorded using Perkin Elmer Spectrum 100 and recorded from the range 4000 to 650 cm-1, UV-Visible spectra were recorded on a Perkin Elmer Lambda 35 spectrophotometer. Molar extinction coefficients (ɛ max, M-1 cm-1) were determined from absorption maxima obtained in the range 200–800 nm, using a 1 cm quartz cuvette. Samples were prepared in methanol and analysed at room temperature. Melting Point was recorded using Buchi M-565 © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Instrument, One dimensional NMR spectra was obtained using 400 MHz Bruker spectrometer in d6DMSO as solvent.All chemical shifts are reported in parts per million (ppm). d = doublet, dd = doublet of doublets, t = triplet,s = singlet, bs = broad singlet, bd = broad doublet, bt = broad triplet. Solvents and starting material. Analytical grade solvents were used for the synthesis of the compounds.Zinc acetate, cadmium acetate, 4-aminobenzoic acid and 4-(dimethylamino) benzoicacid were purchased from Sigma Aldrich.The precursor 5-NO2-phen was synthesized based on already reported synthetic procedure [16]. Antifungal and Antibacterial studies. Antifungal activities of compound 1 were studied against C albicans. Results of anti-fungal activity when compared to standard drug Fluconazole. Antibacterial activity for compound 1 were performed towards different microorganisms which was carried out using MIC determination method. Different microorganisms such as, Gram Positive Staphylococcus aureus (S. aureus), Staphylococcus mutans (S. mutans), and Gram Negative Klebsiella pneumoniae (K.Pneumoniae), Pseudomonas aeruginosa (P.aeruginosa) bacterial strains were used for antibacterial activity of compound 1 and compared with the standard drug Ciprofloxacin. Synthesis Compound 1. Sodium methoxide solution (10 mL) is added to 4-(dimethylamino) benzoic acid (0.1651g,1 mmol) and stirred for 30 minutes. To which zinc (II) acetate dihydrate (0.2195g,1 mmol) was dissolved in methanol (10 mL) and clear methanolic solution (20 mL) of 5-NO2-phen (0.2250g,1 mmol) was added. The resulting solution was stirred for 30 minutes and filtered. The filtrate was kept at room temperature for crystallization. Dark red color crystals were isolated after a few days. Yield: 60 %. mp. 185˚C . Anal. Calcd for C30H27N5O6Zn: C 58.2; H 4.4; N 11.3. Found: C57.9; H 4.2; N 10.9. IR (KBr, cm-1): 3452(s), 1737(m), 1597(s),1516(s), 1354(broad s), 1193(s), 837(s),783(s), UVVis (CH3OH, nm) 206, 225, 299. 1H NMR (400 MHz, DMSO-d6) 2.9 (s, 4CH3), 6.6 (d, aromatic 4CH), 7.7 (d, aromatic 4H), 8.2 (t, phen 2H), 9.0 (d, phen1H), 9.2 (d, phen 2H), 9.4 (d, phen 2H). Compound 2. The compound 2 was synthesized in the similar method of Compound 1.Dark Rediish Brown color crystals were isolated after a few days. Yield: 55 %. MP. 198˚C . Anal. Calcd for C26H19N5O6Cd: C 51.2; H 3.1; N 11.48. Found: C 50.8; H 3.2; N 11.1. IR: 3466(w), 3176(s), 1593(s), 1514(s), 1365(s), 1178(m), 785 (s). UV-Vis (CH3OH, nm) 206,273. 1H NMR (400 MHz, DMSO-d6) 5.4 (s, aromatic 2NH2), 6.5 (d,aromatic 4CH), 7.6 (d,aromatic 4CH), 8.1 (t, phen 2H), 9.0 (d, phen 1H), 9.1 (d, phen,1H,), 9.2 (s, phen,1H), 9.3 (d, phen,1H), 9.4 (d, phen, 1H). Results and Discussion Synthesis. The synthesis of the compound 1and 2 has been achieved by reaction between zinc acetate and sodium methoxide solution is added to 4-(dimethylamino) benzoicacid in the presence of 5-NO2phen ligand (Fig. 1). Both are air stable, soluble in common organic solvents like MeOH, DMF and DMSO and the crystalline products was purified by the recrystallization technique by the slow evaporation method. The results of compound 1 and 2 in elemental analysis shows that the products consistentswith the calculated values in the molecular formula of [Zn(Me2N-C6H4-COO)2(5-NO2phen)] (1) and [Cd(NH2-C6H4-COO)2(5-NO2-Phen)] (2).

Fig. 1. Scheme of Synthesis.

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Spectral Characterization. Compound 1and 2 was characterized by FT-IR spectroscopy. It revealed that monodentate binding mode of aromatic COO – in compound 1 displays asymmetric stretching vibration band νa (COO–) at 1597 cm-1 and wheras for the compound 2 at 1593 cm-1, and symmetric stretching vibration band νs (COO–) at 1365 cm-1 for compound 1 and 1354 cm-1 for compound 2[17].Addtionally, the C-H bending vibration of Phenanthroline ring occurs at 783 cm-1 for compound 1 and 785 cm-1 for compound 2. The 1H NMR spectrum for the compound 1 and compound 2 in DMSO-d6, compound 1 shows the presence of resonances at δ = 2.9 ppm which can be assigned to the protons of the –CH3 group in aromatic rings. The resonance appearing at δ = 6.6 and 7.7 ppm can be assigned to the proton attached to aromatic rings, δ = 8.2 ppm can be assigned to –CH proton attached to aromatic rings, δ = 9.0, 9.2 and 9.4 ppm can be assigned to the proton attached to phen ring, whereas compound 2 shows the presence of resonances at δ = 5.4 ppm can be assigned to the –NH2 attached to aromatic rings and δ=6.5 and 7.6 ppm can be assigned to the proton attached to aromatic rings, δ = 8.1 ppm can be assigned to –CH proton attached to aromatic rings, δ = 9.1, 9.2, 9.3 and 9.4 ppm can be assigned to the proton attached to phen ring. The UV-Vis spectrum of compound 1 and 2 in CH3 OH shows absorption maximum band in the region 200-300 nm for high energy π–π* and n– π* transitions (Fig. 2). Compound 1 has absorption maximum at 299, 225 and 206 nm whereas Compound 2 has absorption maximum at 273 and 206 nm [18].

Fig. 2. UV Vis spectra of compound 1 and 2. Antimicrobial and Antibacterial activity of compound 1. The tested bacterial and fungal strains were prepared in the BHI broth and incubated at 37˚C and 200 rpm in an orbital incubator for overnight.Sample solutions were prepared in DMSO for concentration 100, 50, 25, 12.5, 6.25, 3.12, 1.6, 0.8, 0.4 and 0.2 µg/ml. The standard drug solution of Ciprofloxacin (antibacterial drug) and Fluconazole (antifungal drug) were prepared in DMSO. Serial broth micro dilution was adopted as a reference method. 10 µl solution of test compound was inoculated in 5 ml BHI broth for each concentration respectively and additionally one test tubes was kept as control. Each of the test tubes was inoculated with a suspension of standard microorganism to be tested and incubated at 35˚C for 24 hrs. At the end of the incubation period, the tubes were examined for the turbidity.Turbidity in the test tubes indicated that microorganism growth has not inhibited by the antibiotic contained in the medium at the test concentration Compound 1 demonstrated MIC at concentration 1.6 µg/ml, 25 µg/ml, 0.4 µg/ml, 3.12 µg/ml against K. pneumonia, Pseudomonas, S. aureus, S. mutans respectively and was compared with the standard drug Ciprofloxacin. The results indicate that compound 1 shows moderate antibacterial activity MMSE Journal. Open Access www.mmse.xyz

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

against K. pneumonia, Pseudomonas, S. aureus, S. mutans respectively compound 1 was having good activity in S. aureus, bacterium due to the role of zinc in complex system, coordination and chelating tends are acting as more powerful and influential bacteriostatic agents, thus inhibiting the growth of the microorganisms. The compound 1 were exhibited the growth of C. albicans at concentration 1.6 µg/ml, whereas the standard anti-fungal drug Fluconazole executed antifungal activity at 16 µg/ml. It can be concluded from this study that the tested compound 1 showed more potent anti-fungal activity when compared to standard drug Fluconazole, whereas antibacterial activity is moderate when compared to standard drug Ciprofloxacin. Table 1. Antibacterial and Antifungal activity of compound 1. Concentration of compound 1 (µg/ml)

Drug Organism

100

50 25

12.5

Candida albicans

1.6

0.8

0.4

S. aureus S. mutans

3.12

K. pneumoniae Pseudomonas

6.25

0.2

R R

Summary. Monomeric group 12 metal complexes have been synthesized and characterized by analytical and spectroscopic studies. Compound 1 possesses showed more potent anti-fungal activity when compared to standard drug fluconazole. Compound 1 demonstrated MIC at concentration 1.6 µg/ml, 25 µg/ml, 0.4 µg/ml, 3.12 µg/ml against K. pneumonia, Pseudomonas, S. aureus, S. mutans respectively against Ciprofloxacin, Hence compound 1 to exhibit more potent anti-bacterial and Antifungal activity. Acknowledgement. The authors thank the management of VIT University for providing the excellent research facilities (VIT-SAIF). CG acknowledges Sigma Aldrich, subsidiary of Merck Life Sciences for sponsoring my Ph.D. program. Also, the authors are very much thankful to Maratha Mandal Dental College, Belgaum for performing the antibacterial and antifungal activity. References [1] C.N.R.Rao, S.Natarajan, R.Vaidhyanathan, Angewandte Chemie International Edition, 2004, 1466- 1496. DOI 10.1002/anie.200300588 [2] S.B. Moosun, S. Jhaumeer-Laulloo, E.C. Hosten, T.I.A. Gerber, M.G. Bhowon, Transition Metal Chemistry May 2015,445-458. DOI: 10.1007/s11243-015-9934-1 [3] B. Selvakumar, V. Rajendiran, P.U. Maheswari, H. Stoeckli-Evans, M. Palaniandavar, Journal of inorganic biochemistry, 2006, 316–330. DOI: 10.1016/j.jinorgbio.2005.11.018 [4] K.H. Ibs, L. Rink, Zinc-altered immune function. Journal of Nutrition, 2003, 1452S–1456S [5] B.K.Y. Bitanihirwe, M.G. Cunningham, Zinc: The Brain's Dark Horse. Synapse, 2009, 10291049. DOI: 10.1002/syn.20683.

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[6] A. Mastrolorenzo, A. Scozzafava, C.T, Supuran, Antifungal activity of silver and zinc complexes of sulfadrug derivatives incorporating arylsulfonylureido moieties. European Jorunal of Pharmacuetical Sciences, 2000, 99â&#x20AC;&#x201C;107. [7] M.O. Agwara, P.T. Ndifon, N.B. Ndosiri, A.G Paboudam, D.M. Yufanyi and A. Mohamadou. Bulletin of the chemical society of Ethiopia, 2010, 383-389. DOI: org/10.4314/bcse.v24i3.60680. [8] P. S. Vijendra, Journal of Chemistry and Chemical Sciences, 2014, 70-75. [9] J. W. Nial, I.T. Robin, M.A. Krause-Heuer, R.L. Cook,W. Shaoyu,V.J. Higgins and J. R. AldrichWright, Dalton Transaction, 2007. DOI: 10.1039/b704973k [10] G. Prabusankar, R. Murugavel, Organometallics, 2004, 5644-5647. DOI:10.1021/om049584u. [11]R.Murugavel, S.Banerjee, Inorganic 10.1016/S1387-7003(03)00112-6

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2003,

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DOI:

[12] R. Murugavel, D. Krishnamurthy, M. Sathiyendiran, Journal of the Chemical Society, Dalton Transactions, 2002, 34, DOI: 10.1039/b105687p [13] M.O. Agwara1, P.T. Ndifon1, N.B. Ndosiri1, A.G. Paboudam, D.M. Yufanyi and A. Mohamadou Bulletin of the chemical society of Ethiopia, 2010. DOI: org/10.4314/tjpr.v11i5.15 [14] N. Poulter, M. Donaldson, G. Mulley, L. Duque, N. Waterfield, A. G. Shard, S. Spencer, A. T. A. Jenkins, A. L. Johnson, New Journal of Chemistry. DOI: 10.1039/c4nj01522c [15] M. E. Haque, M. Z. Rahman, M. F. Hossen, M. M. Pervin, M. H. Kabir, K. M. K. Ferdaus, L. Bari, C. M. Zakaria, P. Hassan, M. Khalekuzzaman, J. Applied Sci. 6, 988 2006. [16] G. F. Smith, F.W. CagleJr, Journal of Organic Chemistry, 1947, 781-784. DOI: 10.1021/jo01170a007 [17] K. Senthilkumar, M. Gopalakrishnan, N. Palanisami, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 148, 2015. DOI: org/10.1016/j.saa.2015.03.133 [18] N. Palanisami, K. Senthilkumar, M. Gopalakrishnan, J. Chem. Sci. Vol. 127, No. 5, May 2015. DOI: 10.1007/s12039-015-0843-9 [19] K.S. Patel, J.C. Patel, H.R. Dholariya, V.K. Patel, K.D. Patel, Open Journal of Metal, 2012, 4959. DOI: org/10.4236/ojmetal.2012.23008 Cite the paper Champaka Gurudevaru, Nallasamy Palanisami, (2017). Group 12-Metal Complexes derived from Donor Substituted Carboxylic Acids and 5-Nitro-1,10-Phenanthroline: Spectroscopic and Biological Studies. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.46.5.782

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Spectroscopic Properties of Sm3+Doped Lithium Zinc Borosilicate Glasses7 N. Jaidass1, 2, C. Krishna Moorthi1, A. Mohan Babu1, 2, M. Reddi Babu1, 2 1 – School of Advanced Sciences, V I T University, Vellore - 632 014, India 2 – Dept. of Physics, Chadalawada Ramanamma Engineering College, Tirupati - 517 506, India DOI 10.2412/mmse.4.50.890 provided by Seo4U.link

Keywords: LZBS Glasses, quenching technique, photonic devices, optical amplifiers.

ABSTRACT. For spectroscopic analysis, the Sm3+ ions doped with lithium zinc borosilicate (LZBS) glasses were prepared by the conventional melt quenching technique. The prepared glasses were characterized by the XRD, SEM, optical absorption, luminescence and decay measurements. The XRD spectrum clearly revealed that the LZBS glass is amorphous in nature and the SEM spectrum conformed the same. The UV-VIS-NIR absorption spectra revealed seventeen peaks at 360, 374, 389, 402, 416, 437, 462, 476,526, 562, 943, 1076, 1224, 1369, 1471, 1521 and 1584 nm corresponding to the 6H5/2→4D3/2, 6P7/2, 4L15/2 , 6P3/2, 6P5/2, 4G9/2, 4I13/2, 4I11/2, 4F3/2, 4G5/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2 transitions, respectively. The Judd -Ofelt intensity parameters (Ω2, Ω4 and Ω6) have been determined from the absorption data and these parameters are found to follow the trend as Ω4>Ω6> Ω6. Photoluminescence spectra recorded by the excitation wavelength of 402 nm, revealed four emission peaks at 562, 598, 645 and 713 nm corresponding to 4G 5/2→ 6 H5/2, 6H7/2, 6H9/2 and 6H11/2 transitions, respectively. Radiatiive transition probabilities (AR) peak stimulated emission cross-sections (σe), experimental (βexp) and calculated (βR) branching ratios were determined for different emission transitions. The nature of decay curves of 4G5/2 level for different Sm3+ ions concentrations in the LZBS Smx glasses has been analyzed using Inokuti-Hirayama (I-M) model and the lifetimes (τexp) are found to decrease with increase of Sm3+ ions concentrations.

Introduction. Rare earth doped glasses are more useful materials, in the development of fiber amplifiers, sensors, high optical data storage, laser media and quantum electronic devices [1-4]. For the design of optical devices, host glasses with low phonon energies are essential. Among rare earth ion doped glasses, borosilicate glasses are popular host materials due to their good transparency and easy to draw into fibers for different laser applications. Borosilicate glasses possess excellent optical properties like fluoride glasses with higher chemical durability and better mechanical properties [57]. Moreover, the Sm3+, Dy3+ and Tb3+ ions emit orange, blue and green light, while the Pr3+ ions emit different colors depending on the concentration of dopant ions as well as surrounding environment. In the present work, the emission characteristics of Sm3+ ions in LZBS glasses are determined from the absorption, luminescence and decay measurements. J-O intensity parameters Ωλ (λ= 2, 4 and 6) are determined from the experimental oscillator strengths. The radiatiive transition probabilities (AR), experimental branching ratio (βR), stimulated emission cross-section (σe), gain bandwidth (σex∆λp) and optical gain (σexτR) are evaluated. The concentration quenching phenomenon with concentration variation of Sm3+ ions and the mechanism involved has been discussed. Experimental. LZBS glasses with chemical compositions of (30-x) H3BO3: 25SiO2: 10Al2O3: 30LiF:5ZnO:xSm2O3 were prepared with different Sm2O3 concentrations of 0.1, 0.5, 1.0 and 2.0 mol % by the conventional melt quench technique and are labeled as LZBS Sm01, LZBS Sm05, LZBS Sm10, and LZBS Sm20. About 10g of the batch chemicals were thoroughly mixed and grinded to get homogeneous mixture and heated at 12000C in an electric furnace for 3 hours and then the melt was poured onto a pre-heated brass plate. After casting, the glasses were annealed at 3500C for 7 hours to remove thermal strains and stress. To determine the amorphous nature of the host glass, the XRD © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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spectrum was recorded using the Philips X’Pert - MPD X-ray diffractometer using Cu Kα radiation. The optical absorption spectra were recorded in the region 200 - 2200 nm using JASCO V- 770 UVVIS-NIR spectrophotometer and the photoluminescence excitation and decay measurements were recorded using the FLS-980 spectrofluorimeter. Results and discussion. The XRD spectrum of undoped LZBS glass is shown in the Fig.1. It revealed the absence of sharp peaks in the host LZBS glass and SEM image is shown in the Fig. 2 conformed the amorphous nature of LZBS glass. 40

Intensity (counts)

0 20

Angle (

Fig. 1. (a) XRD pattern of LZBS Sm0.0 glass. Fig. 1. (b) SEM image of LZBS Sm0.0 glass. Optical analysis.To study the optical absorption properties of LZBSSm10 glass, the absorption spectra were recorded in the UV-VIS and NIR regions are shown Figs. 2(a) & (b). The intensities of absorption bands are determined by their oscillation strengths (f), which are directly proportional to the area to the absorption bands. The assignment absorption bands are made by comparing the band positions with those reported by Carnall et al. [8].

0.85 1.5 6

H5/2

D3/2

I13/2

P7/2 4

L15/2

P5/2 4

Absorbance(arb.units)

I11/2

F3/2

G9/2

G5/2

400

450

500

sm 1.0 abs

F7/2

F5/2

F9/2

F3/2 6

H15/2

0.5 6

F1/2

F11/2

0.25 0.5 350

H5/2

P3/2

1.0

550

600

850

1000

650

1200

1400

1600

1800

Wavelength(nm)

Fig. 2. Optical absorption spectrum of LZBSSm10 glass in the (a) UV-VIS regions (b) NIR region. The observed 6H5/2 → 6P3/2 hypersensitivity transition at 402 nm exhibited highest intensity compared to other transitions. The Judd-Ofelt theory [9, 10] has been adopted for the analysis of oscillator strengths of the absorption bands in order to know the nature of bonding between the rare earth ions MMSE Journal. Open Access www.mmse.xyz

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and the surrounding ligands as well as the symmetry around rare earth ions. The experimental (f exp) and calculated (fcal) oscillator strength are determined by finding the relative areas of absorption bands and also using the equations given in previous reports by Reddi Babu et al. [11] . The evaluated J-O intensity parameters of LZBSSm10 glass are compared with those of other Sm3+ doped glasses [1219] in the Table 1. All the J-O parameters follow the trend as  2   4   6 .In the present investigation, the considerably higher magnitude of  2 indicates lower degree of symmetry around the Sm3+ ion and relatively weaker covalence of active ion-oxygen bond. Table 1. Comparison of Judd-Ofelt intensity parameters (in 10-20 cm2) of Sm3+ ions in LZBSSm10 glass along with other reported glasses. System

Ω2

Ω4

Ω6

LZBS Sm10

2.94 9.9

NSBaP

0.33 8.60 3.92 Ω4 >Ω6> Ω2

[12]

L5BS10

6.21 9.68 7.16 Ω4 >Ω6> Ω2

[13]

Bismuth borate

2.10 5.54 4.58 Ω4 >Ω6> Ω2

[14]

Fluorozincate

0.68 3.77 2.15 Ω4 >Ω6> Ω2

[15]

Phosphate

1.50 3.75 1.89 Ω4 >Ω6> Ω2

[16]

LBTAF

0.27 2.52 2.47 Ω4 >Ω6> Ω2

[17]

LCZSFB

3.29 9.16 5.28 Ω4 >Ω6> Ω2

[18]

ZNBS

0.30 3.82 3.65 Ω4 >Ω6> Ω2

[19]

Trend

6.89 Ω4 >Ω6> Ω2

Reference Present work

Photoluminescence and radiative analysis.The emission spectra recorded in the range 500–800 nm for the LZBSSmx (x = 0.1, 0.5, 1.0 and 2.0 mol %) glasses are shown in the Fig. 3. These spectra revealed four emission bands at 562, 598, 645 and 767 nm from the excited 4G5/2 level to the 6H5/2, 6 H7/2, 6H9/2 and 6H11/2 lower transition levels of Sm3+ ion. Among these emissions, the band located at 598 nm corresponding to 4G5/2→6H7/2 is the most intense one. In addition, the emission bands at 598, 647 and 709 nm are important because they are located at the longer wavelength region. The transitions 4G5/2→6 H5/2 (562 nm) and 4G5/2→6H7/2 (592 nm) contain both electric and magnetic dipole contributions, obeying the selection rules, i.e ∆J = 0, +1, while the other two emission transitions 4 G5/2→6H9/2 and 4G5/2→6H11/2 are purely electric dipole transitions [20, 21]. It is observed from the Fig. 3, that the emission intensities are increased upto 0.5 mol% of Sm3+ ions concentrations and then decreased at higher concentrations. The luminescence efficiency of Sm3+ ions doped LZBS emission transitions are found by evaluating the radiative parameters such as transition probabilities (A R), branching ratios (βR), radiative lifetimes (τR) and peak stimulated emission cross sections (σe) for the J   J  emission transitions by using the equations given in previous reports [11]. The efficiency of laser transition mainly depends on the stimulated emission cross-section (σe), gain bandwidth (σe×Δλeff) and optical gain parameters (σe×τexp) [22, 23]. The laser characteristic parameters for the 4 G5/2→ 6H7/2 and 4G5/2→ 6H9/2 transitions in the LZBSSm05 glass are compared with those of Sm3+ doped other hosts [24-29] in Table 2. It is observed that, the σe, βR and βexp values and are comparable with the reported values in different hosts.

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H7/2

G5/2

1.6

Intensity(arb.units)

1.8

1.4

exc=402nm

1.2

em=598nm

H9/2

(a) Sm 0.1 mol % (b) Sm 0.5 mol % (c) Sm 1.0 mol % (d) Sm 2.0 mol %

1.0 0.8

(b)

0.6

H5/2

(c)

0.4

(a) (d)

0.2 0.0 500

550

600

650

H11/2

700

750

wavelength(nm)

Fig. 3. Photoluminescence spectra of Sm3+ ions in LZBSSmx (x = 0.1, 0.5, 1.0 and 2.0 mol %) glasses. Table 2. Comparison of radiative parameters such as emission band positions (λp,nm), effective band widths (Δλeff nm), radiative transition probabilities (AR S-1), peak stimulated emission cross section (σe(×1022 cm2) ), calculated and experimental branching ratios (βR & βexp) LZBSSm05 glass with other glasses. Transition 4G5/2→6H7/2

Transition 4G5/2→6H9/2

Parameters

System

λp

Δλeff

σe

βexp

βcal

λp

Δλeff

σe

βexp

βcal

LZBSm05(Present)

598

12.90

253

12.99

0.48

0.43

645

15.02

182

10.8

0.35

0.31

SLBiBSm05 [24]

603

26.4

177.8

8.34

0.58

0.37

649

29.1

118

7.05

0.19

0.26

TWZSm10 [25]

602

16.73

346

7.7

0.53

0.46

649

17.19

255

7.4

0.25

0.29

PKAPN Sm10 [26]

598

11.2

227

11.5

0.57

0.47

645

11.7

158

10.4

0.25

0.33

0.5LBTPS [27]

605

9.3

215

13.14

0.55

0.43

649

9.5

140

11.0

0.20

0.28

PbFPSm10 [28]

601

13.96

185

8.98

0.57

0.43

648

17.04

171

9.18

0.22

0.40

TMZNB [29]

601

14.7

232

11.70

057

0.4

647

13.8

212

11.0

0.22

0.36

Decay analysis. Fig.4 shows the decay profiles of 4G5/2 excited level for different concentrations of Sm3+ ions in LZBSSmx (x=0.1, 0.5, 1.0 and 2.0 mol %) glasses obtained with excitation wavelength of 402 nm. The decay curves exhibited single exponential nature at lower concentrations (0.1 mol %) and turned into the non-exponential at higher concentrations (0.5, 1.0 and 2.0 mol%) of Sm3+ ions. The single exponential nature is due to either faster decay of excited Sm3+ ions or the negligible interaction between the Sm3+ ions at lower concentrations. The experimental lifetimes with the increase of Sm3+ ions concentration are found to be decreased as 2.23, 1.40, 0.82 and 0.41 ms corresponding to the LZBSSm01, LZBSSm05, LZBSSm10 and LZBSSm20 glasses, respectively. In the present work, at lower concentrations of Sm3+ ions (0.1 mol%), the decay curve is well ﬁtted to single exponential which indicates the absence of energy transfer between the Sm3+ ions, whereas at MMSE Journal. Open Access www.mmse.xyz

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higher concentrations of Sm3+ (0.5, 1.0 and 2.0 mol%), the decay proﬁles turned into non-exponential due to non-radiative energy transfer of the excited ions. The calculated lifetime (τ R) of the 4G5/2 level from the J-O theory for the LZBSSm05 is 1.68 ms.

em= 598nm

(a) sm 0.1mol% (b) sm 0.5mol% (c sm 1.0mol%) (d) sm 2.0mol%

Log Normalised Intensity(arb.units)

ex= 402nm

0.1

(a) (b) (c)

0.01

(d) sm0.1 sm0.5 sm1.0 sm2.0

2.23ms 1.40ms 0.9ms 0.21ms

0.2

0.4

0.6

0.8

Time(ms)

Fig. 4. The decay profiles for the 4G5/2 excited level of Sm3+ ions in LZBSSmx glasses. Summary. Sm3+ ions doped lithium zinc borosilicate glasses (LZBS) were prepared by conventional melt quenching method, and are characterized by different analytical and spectroscopic measurements. The amorphous nature of glass has been confirmed by XRD profiles. The evaluated Judd-Ofelt intensity parameters (Ω2, Ω4 and Ω6) were found to be in the order Ω4 > Ω6 > Ω2 for all the LZBS Sm10 glass. From the emission spectra, it is observed that the intensities of emission peaks increased upto 0.5 mol% and deceased for 1.0 and 2.0 mol% of Sm3+ ions concentrations. The radiative parameters such as transition probabilities (AR), total transition probabilities (AT), branching ratios (βR), radiative lifetimes (τR) and peak stimulated emission cross sections (σe) were calculated for the emission transitions. The large stimulated emission cross sections observed for the 4G5/2→ 6 H7/2 and 4G5/2→ 6H9/2 transitions suggests that, the present glasses are excellent hosts for laser active materials. The decay profiles of the 4G5/2 excited level exhibited single exponential at lower concentrations of Sm3+ ion and turned into non-exponential nature at higher concentrations. Acknowledgement.One of the authors Dr.A.Mohan Babu would like to thanks DST-SERB, New Delhi for the sanction of research project Lr. No. SR /FTP /PS-109/2012 and DAE – BRNS Mumbai for the sanction of major research project No.2012/34/72. Also, N.Jaidass is thankful to DST-SERB, New Delhi for the financial support in the form of Project Assistant in the above project. References [1] Feng Tao,Congrong Hu, Zhijun Wang, Geng Zhu, Yufeng Sun, Da Shu, Ceramics International 39 (2013) 4089–4098. DOI: 10.1016/j.ceramint.2012.10.263. [2] G. Alombert-Goget, C. Armellini, S. Berneschi, A. Chiappini, A. Chiasera, M. Ferrari, S. Guddala, E. Moser, S. Pelli, D. N. Rao, G. C. Righini, Optical Materials 33 (2010) 227–230. DOI: 10.1016/j.optmat.2010.09.030. [3] Abu Zayed Mohammad Saliqur Rahman, Xingzhong Cao, Long Wei, Baoyi Wang,Haichen Wu, Materials Letters 99 (2013) 142–145. DOI: 10.1016/j.matlet.2013.02.078. [4] M. J. Weber, Journal of Non-Crystalline Solids, 123 (1990) 208-222. DOI: 10.1016/0022-3093 (90) 90786-L. MMSE Journal. Open Access www.mmse.xyz

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[5] M. Mortier, A. Monteville, G. Patriarche, G. Maze, F. Auzel, Optical Materials 16 (2001) 255267. DOI: 10.1016/S0925-3467 (00) 00086-0. [6] G. Venkataiah, C. K. Jayasankar, K. Venkata Krishnaiah, P. Dharmaiah, N. Vijaya, Optical Materials 40 (2015) 26–35. DOI: 10.1016/j.optmat.2014.11.042. [7]S.Murugesan, B. Bergman, DOI:1016/j.electacta.2007.06.080.

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Acta

(2007)

8064.

[8] W T Carnall. Handbook on the Physics and Chemistry of Rare Earths 1979. [9] B. R. Judd, Physical Review 127 (1962) 750-761. DOI: 10.1103/PhysRev.127.750. [10] G. S Ofelt, Journal of Chemical Physics 37 (1962) 511-520. DOI: 10.1063/1.1701366. [11] M. Reddi Babu, N. Madhusudhana Rao, A. Mohan Babu, N. Jaidass, C. Krishna Moorthi, L. Rama Moorthy. Effect of Dy3+ ions concentration on optical properties of lead borosilicate glasses for white light emission. Optik 2015; 127:3121-3126. DOI:10.1016/j.ijleo.2015.12.018. [12] P. Raghava Rao, G. Murali Krishna, M. G. Brik, Y. Gandhi, N. Veeraiah, Journal of Luminescence,131(2011) 212-217. DOI:org/10.1016/j.jlumin.2010.09.044. [13] C. K. Jayasankar, P. Babu. Journal of Alloys compd. 307 (2000) 82-95. DOI: 10.1016/S09258388 (00) 00888-4. [14] A. Ali, Journal of Luminescence, 129 (2009) 1314- 1319 DOI: 10.1016/j.jlumin.2009.06.017. [15] V. D. Rodríguez, I. R. Martín, R. Alcalá, R. Cases Journal of Luminescence, 54 (1992) 231-236. DOI: 10.1016/0022-2313(92)90070-P. [16] M. Seshadri, K. VenkataRao, J. L. Rao, Y. C. Ratnakaram, Journal of Alloys and Compounds 476 (2009) 263-270. DOI: 10.1016/j.jallcom.2008.09.033. [17] B. C. Jamalaiah, J. Sureshkumar, A. Mohan Babu, T. Suhasini, L. Rama Moorthy, Journal of Luminescence 129 (2009) 363-369. DOI: 10.1016/j.jlumin.2008.11.001. [18] C. Madhukar Reddy,G. R. Dillip, K. Mallikarjuna, S. Zulifiqar Ali Ahamed, B. Sudhakar Reddy, B. Deva Prasad Raju, Journal of Luminescence 131 (2011) 1368-1375 DOI:10.1016/j.jlumin.2011.03.016. [19] C. K. Jayasankar, E. Rukmini, Optical Materials 8 (1997) 193-205. DOI: 10.1016/S0925-3467 (97) 00021-9. [20] N. Srisittipokakuna, J. Kaewkhao, Proceedings of the 4th II AE International Conference on Industrial Application Engineering 2016. DOI:2.ia-engineers.org/iciae2016/. [21] K. Devlin, B. O’ Kelly, Z.R. Tang, C.Mc. Donagh, J.F.Mc. Gilp, Journal of Non-Crystalline Solids 135(1991)8-14.DOI:10.1016/0022-3093(91)90436-A. [22] M. Seshadri, K. VenkataRao, J. L. Rao, Y. C. Ratnakaram, Journal of Alloys and Compounds 476 (2009) 263-270. DOI: 10.1016/j.jallcom.2008.09.033. [23] M. Chandra Shekhar Reddy, B. Appa Rao, M.G. Brik, A. Prabhakar Reddy, P Raghava Rao, C. K. Jayasankar, N. Veeraiah, Applied Physics B108 (2012) 455–461.DOI: 10.1007/S00340-012-4983Z. [24] D. Rajesh, A. Balakrishna, Y. C. Ratnakaram, Optical Materials 35 (2012) 108-116. DOI: org/10.1016/j.optmat.2012.07.011. [25] G. Venkataiah, C. K. Jayasankar, K. Venkatakrishnaiah, P. Dharmaiah, N.Vijaya. Optical Materials 40 (2015) 26-35. DOI:ORG/10.1016/J.OPTMAT.2014.11.042. [26] Ch. Basavapoornima, C. K. Jayasankar, Journal of Luminescence, 153 (2014) 233– 241. DOI: 10.1016/j.jlumin.2014.03.006. MMSE Journal. Open Access www.mmse.xyz

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[27] S. Selvi, K. Marimuthu, G. Muralidharan, Journal of Luminescence 159 (2015) 207-218. DOI:ORG/10.1016/J.JLUMIN.2014.11.025. [28] C. R. Kesavulu, C. K. Jasankar, Journal of Luminescence, 132 (2012) 2802-2809. DOI: 10.1016/j.jlumin.2012.05.031. [29] O. Ravi, C. Madhukarreddy, L. Monoj, B. Devaprasad Raju. Journal of Molecular Structure 1029 (2012) 53-59. DOI: 10.1016/j.molstruc.2012.06.059. Cite the paper N. Jaidass, C. Krishna Moorthi, A. Mohan Babu, M. Reddi Babu, (2017). Spectroscopic Properties of Sm3+Doped Lithium Zinc Borosilicate Glasses. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.4.50.890

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Spectral Analysis of Nd3+ Doped Lead Borosilicate Glasses for Efficient Broadband Laser Amplification8 M. Reddi Babu1, 2, N. Madhusudhana Rao1, A. Mohan Babu1, 2 1 – School of Advanced Sciences, V I T University, Vellore - 632 014, India. 2 – Dept. of Physics, Chadalawada Ramanamma Engineering College, Tirupati - 517 506, India. DOI 10.2412/mmse.59.84.971provided by Seo4U.link

Keywords: lead borosilicate glasses, JO analysis, intensity parameters, emission analysis, concentration quenching. ABSTRACT. In this investigation, Nd3+ doped lead borosilicate glasses (LBS) were prepared with chemical composition of (30-x) PbO – 40 H3BO3 –10 SiO2 – 10 Al2O3 – 10 LiF – x Nd2O3 (where x varies from 0.0, 0.1, 0.5, 1.0 and 2.0 mol%) by conventional melt-quenching method. The spectroscopic analysis can be done using absorption, emission and decay measurements. The oscillator strengths (fexp and fcal) and the evaluated Judd-Ofelt (JO) intensity parameters (Ωλ, λ = 2, 4 and 6) determined from the absorption spectrum. From the emission spectra, three NIR bands observed at 903, 1060 and 1334 nm corresponding to the 4F3/2→4I9/2, 4F3/2 →4I11/2 and 4F3/2 →4I13/2 transitions, respectively for which the effective bandwidths (ΔλP), radiative transition probabilities (AR) branching ratios (βR) and stimulated emission cross-sections (σse) are also evaluated. The intensities of emission bands increased with the increase of Nd 3+ ions concentration upto 1.0 mol% and then decreased at higher concentrations due to the concentration quenching. From the analysis of emission properties, it is concluded that the Nd3+ doped LBS glasses could be useful for various photonic applications in different fields.

Introduction. In the present scenario, the multicomponent oxide glasses have been attracted the several researchers and technologists due to their unique properties such as trouble-free casting, good transparency, solubility of rare earth ions and long term stability [1]. However, due to the increasing demand of the rare earth doped multi-component oxide laser glasses in various applications such as higher order harmonic generation [2], time-resolved laser spectroscopy [3], plasma generation [4] and in many areas, a good host is highly essential to improve the quantum efficiency to meet the aforesaid applications. In the process of searching various oxide glasses, the host glasses with heavy metallic components such as lead oxide, aluminum oxide and silicon dioxide are found to have the ultrafine transparency, high thermal stability, low melting point, infrared transparency, corrosion resistance and also good solubility of rare earth ions [5]. In these multiconstituents, the role of lead in the glass network is to reduce the phonon energy of borate (~1400cm-1) and also to increase the mechanical stability by lowering the melting temperature. Hence, in the present study lead borosilicate glasses (LBS) are chosen as a host matrix to meet the specified applications. Among the available rare earth ions, the neodymium (Nd3+) ion is identified as one of the most efficient ions for solid state lasers with the emission wavelength at 1060 nm as well as the possibility for lasing action at other wavelengths such as 1800, 1350 and 880 nm which are be useful for broadband laser amplifiers and other photonic applications. Experimental. High purity reagents of PbO, H3BO3, SiO2, Al2O3, LiF and Nd2O3 (99.99) were selected as raw materials for the preparation of Nd3+ doped lead borosilicate (LBS) glasses by the melt-quench procedure. Results and Discussion. Due to the absorption of energy by the ground state ( 4I9/2) Nd3+ ions, they get excited to the various excited levels. The absorption spectrum of Nd 1.0:LBS glass recorded in the © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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wavelength region of 400 - 950 nm is shown in the Fig. 1. It shows eleven absorption bands at 430, 460, 477, 513, 526, 583, 627, 682, 747, 804 and 875 nm are identified corresponding to the transitions 4 I9/2â&#x2020;&#x2019; 2P1/2, 4G11/2, 2G9/2, 4G9/2, 4G7/2, 4G5/2, 2H11/2, 4F9/2, 4F7/2, 4F5/2 and 4F3/2, respectively. The assignments of the transitions have been done based on the reports by the Carnal et.al [6]. Among these energy levels, the 2P1/2, 4G11/2, 2G9/2, and 2H11/2 levels are not well resolved due to the strong absorption of the host composition. The observed absorption bands in the present work are similar to those of other Nd3+ doped glasses, which indicate homogeneous incorporation of the rare earth ions in the glass network. It is also noticed that the bands at 526, 583, 747 and 804 nm are more intense than other bands. In the case of rare earths ions certain transitions are sensitive to ligand environment of the host and such transitions are called as hypersensitive transitions, obeying the selection rules Î&#x201D;Jâ&#x2030;¤2, Î&#x201D;Lâ&#x2030;Ľ2 and Î&#x201D;S = 0. These transitions posses higher reduced matrix elements (||U 2|| and also higher oscillator strengths with respect to other transitions. In the case of Nd 3+ ion, the 4I9/2â&#x2020;&#x2019;4G5/2 is the hypersensitive transition and possesses higher oscillator strength.

Fig. 1.(a) Absorption and (b) Emission spectra of Ndx:LBS glasses Judd-Ofelt analysis.To investigate the nature of bonding exists between the rare earth ions and the surrounding ligands and as well as the symmetry around the rare earth ions, the JO analysis has been adopted. The JO theory enables the evaluation of intensity parameters â&#x201E;Ś Îť (Îť = 2, 4 and 6), which are useful to know the nature of the bonding, asymmetry and also in the prediction of certain radiative parameters. To evaluate the JO intensity parameters, the experimental (f exp) and calculated (fcal) oscillator strengths are determined using the expressions given in earlier reports by Reddi Babu et al. [1] and are reported in Table 1. The evaluated intensity parameters ď &#x2014; Îť (Îť = 2, 4 and 6) of the Nd1.0: LBS glass are compared with those of other Nd3+ doped glasses as presented in the Table 2 [7-10]. Emission analysis.The emission spectra of Nd x:LBS (x=0.1, 0.5, 1.0 and 2.0 mol %) glasses recorded in the region 800-1500 nm with an excitation wavelength of 808 nm are shown in the Fig 1(b). It is also observed that the emission intensities increases with the increase of Nd 3+ ions concentration upto 1.0 mol% and then decreases at higher concentrations. It may be due to concentration quenching as well as the energy transfer between the Nd3+ ions. Among the emission transitions, the 4F3/2 â&#x2020;&#x2019; 4I11/2 transition at 1060 nm is found be more intense than the other transitions. In order to predict the lasing efficiency of Nd3+ doped LBS glasses, the evaluated Judd-Ofelt intensity parameters ď &#x2014; Îť (Îť = 2, 4 and 6) are used to calculate the radiative properties such as spontaneous emission probabilities (AR), total radiative transition probability (AT), radiative lifetimes (Ď&#x201E;R) and branching ratios (Î˛R) for the 4 F3/2â&#x2020;&#x2019;4I9/2, 4I11/2 and 4I13/2 emission transitions using the expressions available in previous reports [1] and are shown in Table 2. From the data, the higher experimental branching ratios are observed for the 4F3/2â&#x2020;&#x2019; 4I11/2 transition at 1060 nm for all the Nd+3 doped LBS glasses which is useful for high gain broadband amplification applications. Also, certain laser characteristic parameters such as stimulated emission cross-sections (Ď&#x192;e), optical gain bandwidths (đ?&#x153;&#x17D;đ?&#x2018;&#x2019; Ă&#x2014; Î&#x201D;đ?&#x2018;&#x2019;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C; ) and optical gain MMSE Journal. Open Access www.mmse.xyz

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parameters (đ?&#x153;&#x17D;đ?&#x2018;&#x2019; Ă&#x2014; Ď&#x201E;đ?&#x2018;&#x2026; ) are calculated using the expressions [1] and are presented in Table 3. From the tabulated data, the Nd0.5:LBS glass possess higher values of Ď&#x192; e, (đ?&#x153;&#x17D;đ?&#x2018;&#x2019; Ă&#x2014; Î&#x201D;đ?&#x2018;&#x2019;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C; ) and (đ?&#x153;&#x17D;đ?&#x2018;&#x2019; Ă&#x2014; Ď&#x201E;đ?&#x2018;&#x2026; ) for the 4 F3/2â&#x2020;&#x2019;4I11/2 transition observed at 1060 nm. Table 1. Comparison of Judd-Ofelt intensity parameters (in 10-20 cm2) of the Nd1.0 :LBS glass with other Nd3+ doped host glasses. â&#x201E;Ś2

Glass matrix

â&#x201E;Ś4

â&#x201E;Ś6

Trend

Nd1.0:LBS [Present work] 10.96 1.62 19.87

â&#x201E;Ś6>â&#x201E;Ś2 >â&#x201E;Ś4

30B2O3-70PbO[7]

3.52

2.98 5.48

â&#x201E;Ś6>â&#x201E;Ś2 >â&#x201E;Ś4

30PbO-70B2O3 [7]

3.96

3.77 4.68

â&#x201E;Ś6>â&#x201E;Ś2 >â&#x201E;Ś4

ZBLAN [8]

5.09

3.12 7.16

â&#x201E;Ś6>â&#x201E;Ś2 >â&#x201E;Ś4

Silicate[9]

4.71

4.54 5.05

â&#x201E;Ś6>â&#x201E;Ś2 >â&#x201E;Ś4

Vitreous Borate[10]

4.3

3.6

â&#x201E;Ś6>â&#x201E;Ś2 >â&#x201E;Ś4

4.7

Table 2. Different radiative parameters of the Ndx:LBS (x= 0.1, 0.5, 1.0 and 2.0mol%) glasses. Property

Nd0.1:LBS

Nd0.5:LBS LBS

Nd1.0:LBS LBS

Nd2.0:LBS

1368

5117

4356.1

5942

7221

13054

11013

13083

Î˛m

0.35

0.26

0.25

0.45

Î˛R

0.19

0.39

0.4

0.21

Ď&#x201E;R(Âľs)

138

4623

6542

5492

5999

7221

13054

11013

13083

F3/2 â&#x2020;&#x2019; 4I11/2 Î˛m

0.55

0.65

0.66

0.46

Î˛R

0.64

0.50

0.69

Ď&#x201E;R(Âľs)

138

1172

1328

1109

1087

7221

13054

11013

13083

0.1

0.09

0.1

Î˛R

0.16

0.10

Ď&#x201E;R(Âľs)

138

Transition

F3/2 â&#x2020;&#x2019; 4I9/2

F3/2 â&#x2020;&#x2019; 4I13/2 Î˛m

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Table 3. Laser characteristic parameters of the Ndx:LBS (x= 0.1, 0.5, 1.0 and 2.0 mol%) glasses. Transition

F3/2 → 4I9/2

F3/2 → 4I11/2

F3/2 → 4I13/2

Lasing parameter

Nd0.1:LBS

Nd0.5:LBS Nd1.0:LBS

Nd2.0:LBS

λP

903

902

904

902

Δλeff

58.55

53.15

52.26

45.87

σe

0.89

3.57

3.08

4.62

σe× Δλeff

5.21

18.98

16.09

21.20

σe× τR

1.23

3.50

2.53

3.51

λP

1059

1060

ΔλP

35.81

39.54

39.90

39.91

σe

9.32

11.64

9.56

10.22

σe× Δλeff

33.38

46.02

38.15

40.79

σe× τR

12.86

11.05

7.83

7.76

λP

1334

1337

1334

ΔλP

67.53

56.36

53.44

63.57

σe

3.16

4.18

3.67

2.92

σe× Δλeff

21.35

23.56

19.62

18.57

σe× τR

4.36

3.97

3.00

2.21

Summary. In the present work, different concentrations of the Nd3+ doped LBS glasses were prepared by the melt-quench method and are characterized by using the absorption and emission measurements. Using the absorption studies, the JO intensity parameters (Ωλ) were determined from the absorption spectrum of Nd1.0: LBS glass and their trend has been observed as Ω6>Ω2 >Ω4. The higher Ω6 parameter of the LBS glass indicates more rigidness of the glass and also strong electronphonon coupling strengths between the Nd3+ ions and anion ligands. The radiative properties such as transition probabilities (AR), total transition probabilities (AT), branching ratios (βR), radiative lifetimes (τR) and peak stimulated emission cross sections (σ e), optical gain bandwidths (σ e×Δλeff) and optical gains (σe×τexp) were calculated for all the emission transitions of the Nd 3+ doped LBS glasses. The higher values of stimulated emission cross sections, optical gain bandwidth and optical gain observed, for the 4F3/2→ 4I11/2 transition at 1060 nm suggests that, the prepared glasses are highly useful for efficient broadband laser amplification applications. From the decay profiles of the 4 F3/2→4I11/2 transition of Nd3+ ion, it is concluded that, lifetimes (τexp) of the 4F3/2 level decreased with the increase of Nd3+ ion concentrations. Acknowledgements. One of the authors Dr. A. Mohan Babu would like to thank DAE – BRNS, Mumbai, (Letter No.2012/34/72/BRNS) and DST-SERB, New Delhi, (Letter. No. SR/FTP/PS109/2012) for the sanction of research projects. Also, Mr. M. Reddi Babu is thankful to DAE – BRNS, Mumbai for the financial support in the form of SRF in the above project.The authors also grateful to Prof. C. K. Jayasankar, Department of Physics, Sri Venkateswara University, Tirupati for providing lab facilities to carry our the research work. References

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[1] Reddi Babu M, Madhusudhana Rao N, Mohan Babu A, Jaidass N, Krishna Moorthi C, Rama Moorthy L. Effect of Dy3+ ions concentration on optical properties of lead borosilicate glasses for white light emission. Optik 2015; 127:3121-3126. DOI:10.1016/j.ijleo.2015.12.018. [2] Kemper A F, Moritz B, Freeicks J K, Devereaux T P. Theoretical description of high - order harmonic generation in solids. New Journal of Physics 2013; 12:1-15. DOI:10.1103/PhysRevLett.113.073901. [3] Chemla, D S, Jagdeep Shah. Many-body and correlation effects in semiconductors. Nature 2011; 411:549-557. DOI: 10.1038/35079000 [4] Straw M, Randolph S. Direct spatiotemporal analysis of femto second laser-induced plasmamediated chemical reactions. Laser Physics Letters 2014; 11:035601-035608. DOI:10.1063/1.3157908. [5] Reddi Babu M, Madhusudhana Rao N, Mohan Babu A, Jaidass N, Krishna Moorthi C, Rama Moorthy L. Structural and Luminescent Investigation of Eu3+ Doped Lead Borosilicate Glasses. AIP Conference Proceedings 2016; 1728: 1-15. DOI: 10.1063/1.4946468. [6] Carnall W T. Handbook on the Physics and Chemistry of Rare Earths 1979. [7] Saisudha M B, Ramakrishna J. Effect of host glass on the optical absorption properties of Nd3+, Sm3+ and Dy3+ in lead borate glasses. Physical Review B, 1996; 53:6186-6196. DOI:https://doi.org/10.1103/PhysRevB.53.6186 [8] Kedziorski A, Smentek L. New parametrization of spectra of Nd3+ and Sm3+ in glasses, Journal of Alloys and Compounds 2008; 451:686-690. DOI.org/10.1016/j.jallcom.2007.04.069 [9] Suzuki T, Nasu H, Hughes M, Mizuno S, Hasegawa K, Ito H, Ohishi Y. Quantum efficiency measurements on Nd - doped glasses for solar pumped lasers. Journal of Non-Crystalline Solids 2010; 356:2344-2349. DOI.org/10.1016/j.jnoncrysol.2010.03.037. [10] Bremer K, Pal A, Yao S, Lewis E, Sen R, Sun T, Grattan K T V. Sensitive detection of CO 2 implementing tunable thulium - doped all - fiber laser. Applied Optics 2013; 52:3957-3963. DOI.org/10.1364/AO.52.003957. Cite the paper M. Reddi Babu, N. Madhusudhana Rao, A. Mohan Babu (2017). Spectral Analysis of Nd3+ Doped Lead Borosilicate Glasses for Efficient Broadband Laser Amplification. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.59.84.971

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Growth and Characterization of a Nonlinear Optical Crystal a Complex Orthonitroaniline with Picric Acid Single Crystal by Vertical Bridgman Technique9 S. Noormohammad Shareef1, K Chidambaram2, S. Kalainathan1, a 1 – Centre for Crystal Growth, VIT University, Vellore 632 014, Tamil Nadu, India 2 – Sensor Laboratory, Department of Physics, SAS, VIT University Vellore - 632 014, Tamil Nadu, India. a – kalainathan@yahoo.com 7 DOI 10.2412/mmse.39.72.787 provided by Seo4U.link

Keywords: Vertical Bridgman Technique, organic compounds, NLO materials characterization.

ABSTRACT. Single crystal of organic NLO material Orthonitroaniline with picric acid (2[C6H6N2O2]-C6H2(NO2)3OH) (ONAP) of dimensions 27mm length and 12mm of diameter was grown from melt using vertical Bridgman technique. The grown crystal was confirmed with monoclinic structure by single crystal X-ray diffraction studies. Fourier transform infrared spectroscopy was used to assign various modes and to identify the functional groups present in the crystal. The presence of title compound was confirmed by NMR studies. The suitability for laser applications for the reported crystal was confirmed with UV-Vis studies.

Introduction. Organic crystals have been recognized as the materials of the future, due to their molecular nature, added with the versatility of synthetic chemistry helpful in changing and control their molecular structure, leading to the betterment of NLO properties [1]. The second order nonlinear optical material properties of the molecules are highly studied for potential applications, such as optical signal processing and optoelectronics [2]. Some crystals are highly polar due to their noncentro symmetric crystal nature, photonic crystals having band gap in the visible range are not noticed and is linked with some properties like refractive index, symmetry of the crystal and lattice spacing [3]. The grown crystal ONAP is easily polarisable based on the intermolecular properties. One of the important reasons for the selection of present compound is its inter molecular interaction between the pairs of orthonitroaniline and that of picric acid is well established that picric acid forms crystalline picrates with many organic molecules [3].and also a bulk size crystal is aimed to grow in this technique. The present crystal's melting point was reported to be 80 ̊ C [3] and it was found to be monoclinic crystal system having space group Cc [4]. For few organic materials solution growth methods are not good because of solvent or compound associations forming during the crystal growth and solvent inclusions can reduce the optical quality. Melt growth techniques are rapid and suitable for growing organic crystals [5]. The vertical Bridgman technique is simple and is the best technique for the growth of good organic and inorganic crystals in a limited period. The single wall ampoule with conical tip is very useful to grow good quality transparent crystals. In the present work Orthonitroaniline with picric acid (2[C6H6N2O2]-C6H2(NO2)3OH) (ONAP) single crystal was grown using the single wall ampoule by the vertical Bridgman technique. Experimental procedure. High purity orthonitroaniline (99%) and picric acid (99%) were weighed according to the stoichiometry of 2:1 [3]. and loaded in a borosil glass ampule. The cone length and angle of the cone are 25mm, 12 ̊ respectively and ampoule of 1 mm thick was chosen for ONAP single crystal growth. Most of the cases ampoules which are conical in shape produce good quality © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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crystals; The conical tip of the ampoule is the place of initiation of the solidification and controls the growth. The crystal quality increases if the cone length is more, and cone angle was found to be the most optimum to obtain inclusion-free good quality transparent crystals [5]. Before filling the chemicals in the ampoule, it was cleaned and dried well in order to prevent the generation of defects due to the presence of impurity. The ampoule then was evacuated to 10-6Pa and was placed in a two zone resistance furnace after sealing it, in a favourable melting point inside the furnace which was noted from the profile as shown in the Fig (1). For growing different single crystals distribution of the temperature inside the furnace and its gradient are much important in this technique [6]. A two zone VBT technique was optimized and a temperature gradient of 2 ̊C/cm was maintained. In this VBT set up contains a furnace, with a temperature controller with a variation of 0.1 ̊C, a translation assembly and a super kandal wire which was used as a heating element. The ampoule was kept at a height of 22cm in the two zone furnace and was slowly translated inside the furnace in order to achieve crystallization. The materials that have lower thermal conductivity take more time to solidify from the melt. For this reason, organic crystals are grown at a slower rate. The growth rates of organic materials should not exceed 1mm/h, while growth rates for metals and inorganic substances may reach 20mm/h [7]. so 0.5mm/hr translation was given, the crystallization of the molten ONAP was initiated by self-nucleation and crystal growth started and continued through the length of the melt. The heating profile was reduced slowly to room temperature at a rate of 4 ̊C/h in order to avoid cracks due to the difference in the thermal expansion coefficient between the glass and the crystal , after a week the run was completed and the crystal was removed using a diamond wheel cutter. Finally a red coloured transparent crystal of 27mm length and 12 mm of diameter was obtained . As grown crystal and cut and polished crystals are shown in the Fig(2).

Fig. 1. Temperature profile of two zone vertical bridgman furnance ,Fig.2. photograph of as-grown crystal by vertical Bridgman method inset showes cut and polished Orthonitroaniline crystal. Results and Discussions Single crystal XRD analysis.XRD data was retrieved from single crystal X-ray diffractometer (An Envarf Nonius CAD4) for grown ONAP single crystal using MoKὰ as a source with wave length of 0.717073 Å radiation to identify the structure and lattice parameter values. The grown crystal was found to be monoclinic crystal system with the space group Cc. The observed and reported cell parameter values are tabulated in table 1 the inferred cell parameters values are in good agreement with the reported values [3] .

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Table 1. Unit cell parameters of ONAP crystal. Parameter Present value (VBT)

Reported value (SSET)[3]

a(Å)

10.4 Å

10.366 Å

b(Å)

15.29 Å

15.139Å

c(Å)

14.97 Å

14.091 Å

β(Å)

114.7֯̊

106.76̊

V(Å3)

2180 Å3

FT-IR spectrum.The recorded IR radiation for ONAP crystal is shown below Fig 3. In the frequency region the peaks 3580 cm-1 was attributed due to the O-H stretching vibration of picric acid. The below assigned peaks of various functional groups are shown in Table 2 confirm the formation of the ONAP.

100

3000

2000

1000

433.98

663.51 526.57 462.92

748.38 713.66 694.37

918.12

1149.57 1099.43 1082.07 1247.94

1319.31 1280.73

1500

500 1/cm

405.05

4000 2 NITRO

1344.38

1500.62

1427.32

1602.85 1544.98 1622.13

1469.76

989.48

1737.86

3373.50

3487.30

3093.82

2335.80

Fig .3. FTIR spectrum of Orthonitroaniline single crystal. Table 2. Observed spectral data of ONAP. S. No 1 2

FT-IR 748.38 918.12

Assignments C-H bending C-H bending

1247.94

1344.38

Phenolic CO stretching NO2 symmetric stretching

S.No 5 6 7

FT-IR 1622.13 3093.82 3487.30

Assignments NH bending CH symmetric stretching NH2 vibration

NMR Studies.1H nuclear magnetic resonance spectrum of ONAP was recorded by using Bruker MMSE Journal. Open Access www.mmse.xyz

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400MHz spectrometer with tetra methyl silane as internal standard. 1H NMR spectrum was taken by dissolving the material in CDCl3 solvent and is shown in Fig. 4. A peak observed at 7.26ppm was mainly due to the CDCl3 solvent and a triplet peak found at 6.67ppm was attributed to the hydrogen atom present in the third position of the title compound. The doublet peak found at 8.09 and 8.07ppm ascribed to hydrogen atom present in second position of the compound. The triplet peak at 7.32, 7.34 and 7.36 ppm was corresponds to the hydrogen atom present in the fourth position of the title material. The doublet peak observed at 6.71and 6.81ppm shows the presence of hydrogen atom in the fifth position of the ring. The resonance singlet at 9.175ppm was due to the hydrogen atom present in the picric acid. Thus, the above observations indicates the presence of title compound.

Fig. 4. NMR spectrum of ONAP. UV -Vis-NIR studies.Transmission range, low cut of wavelength and absorption band of a crystal are important parameters for a crystal to use it in laser frequency conversion applications [8]. The UV-vis spectrum also gives the information about structure of a molecule [9,10]. The uv visible spectral analysis was carried out between 400 and 1100 nm using Perkin-Elmer Lambda-35 spectrophotometer for 1.9 mm thick ONAP crystal which is shown in the Fig .5. The ONAP crystal has lower cut off wavelength at 508 nm, the crystal is found to be transparent in the 508-1100 frequency range. The peak below 400 nm is due to the presence of π-π* transitions. The optical band gap of ONAP crystal was found to be 2eV calculated from Tauc's plot. The lower band gap of the titled compound (ONAP)can be used for visible light responsive devices and ambipolar organic thin films, transistors [10].

Fig. 5. (a) UV-Vis spectrum of Orthonitroaniline (b) optical band gap spectrum of Orthonitroaniline. MMSE Journal. Open Access www.mmse.xyz

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Laser damage threshold.LDT for crystals is important as it constrains on the crystals applications. The exposure of high intense light on the crystals plays an vital role in NLO devices, electro optic modulators and frequency production of third order generations which mainly involves the capacity to withstand high intense laser light [11]. If LDT value is low the crystal will not have much applications even for good SHG crystals[12]. The laser damage threshold (LDT) of NLO components such as frequency doublers parametric oscillators, pockels cells depends on physical and chemical imperfections particularly on growth dislocations and LDT is influenced by the dislocations and the crystal with many dislocations presented low damage threshold[13]. The laser damage threshold study was performed on ONAP crystal using Q-switched Nd:YAG laser of 1064 nm as a fundamental wavelength with a pulse duration of 10 ns. A small dot was visible on the sample when the energy was 129mJ and a crack appeared on the crystal surface. To calculate each laser pulse's energy a combined phototube oscilloscope was used. The power density for ONAP was also calculated. The LDT value of ONAP was found to be 2.57 GW/cm2 which is much higher than that of KDP(0.20 GW/cm2 ), LiNbO3(0.3 GW/cm2), KNbO3 (1GW/cm2 ) [14]. Summary. ONAP single crystal in bulk size was grown for the first time by vertical Bridgman technique. The unit cell parameters are matched with the reported values. The fundamental groups were found from FTIR studies. The band gap and absorption coefficient were determined from UVVis spectrum and the material is suitable for laser applications. The NMR study report confirms the presence of titled compound LDT value for the grown crystal was calculated and the crystal can be used in laser devise instruments. Acknowledgement The authors gratefully acknowledge VIT management for providing facility and financial support. References [1] M.D.Aggarwal et.al, Modified Bridgman-Stockbarger growth of a novel NLO organic crystal (2ethoxyphenyl)-methylene propanedinitrile, J. cry. growth , 166.1 (1996) 542-544. 10.1016/00220248(95)00500-5 [2] G.Anandha Babu et.al, Investigation of crystal growth, structural, optical, dielectric, mechanical and thermal properties of a novel organic crystal 4,4'dimethylbenzophenone, Journal of Crystal Growth 310 (2008) 3561– 3567. org/10.1016/j.jcrysgro.2008.05.023 [3] S.Anandhi et.al Studies on growth, thermal, optical, vibrational properties and hyperpolarizability of a complex orthonitroaniline with picric acid, Journal of Crystal Growth 312 (2010) 3292–3299. doi.org/10.1016/j.jcrysgro.2010.08.007 [4] K.Senthil et.al, Synthesis, growth, structural and HOMO and LUMO, MEP analysis of a new stilbazolium derivative crystal: A enhanced third-order NLO properties with a high laser-induced damage threshold for NLO applications, Optical Materials 46 (2015) 565–577. doi.org/10.1016/j.optmat.2015.05.029 [5] T.Suthan, N.P.Rajesh, Growth and characterization of organic material 4-nitrobenzaldehyde single crystal using modified vertical Bridgman technique, Journal of Crystal Growth 312 (2010) 3156–3160. org/10.1016/j.jcrysgro.2010.08.002 [6] SP.Prabhakaran et.al, Studies on the growth, structural, optical, mechanical properties of 8hydroxyquinoline single crystal by vertical Bridgman technique, Materials Research Bulletin 46 (2011) 1781, doi.org/10.1016/j.materresbull.2011.08.001 [7] T.Suthan et.al,Growth and characterization of organic material 3-hydroxybenzaldehyde single crystal by modified vertical Bridgman technique, Spectrochimica Acta Part A 87 (2012) 194– 198. doi.org/10.1016/j.saa.2011.11.036

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[8] P. Vivek, P.Murugakoothan, Growth and anisotropic studies on potential nonlinear optical crystal imidazole–imidazolium picrate monohydrate (IIP) in different orientations for NLO device fabrications, Optics & Laser Technology 49(2013)288–295. doi.org/10.1016/j.optlastec.2013.01.015 [9] P. Kalaiselvia et.alGrowth structural, spectral, optical and mechanical studies of gammabis glycinium oxalate (GBGOx) new NLO single crystal by SEST method, Optik 125 (2014) 1825– 1828. doi.org/10.1016/j.ijleo.2013.09.042 [10] M. Nirosha et.al, Growth and characterization of a new organic single crystal 1-(4-Nitrophenyl) pyrrolidine (4NPY), Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 138 (2015) 370–374. doi.org/10.1016/j.saa.2014.11.086 [11] N. Sivakumar et.al, Growth, crystalline perfection, optical, thermal, laser damage threshold and electrical characterization of melaminium levulinate monohydrate single crystal, Journal ofCrystalGrowth426(2015)86–94. doi.org/10.1016/j.jcrysgro.2015.05.025 [12] Redrothu Hanumantharao, S. Kalainathan, Crystal growth and optical studies on a semi organic nonlinear optical material for laser blue-green generation, Optik 124 (2013) 2204– 2209. org/10.1016/j.ijleo.2012.06.098 [13] M. Senthil Pandian, P. Ramasamy, Sodium sulfanilate dihydrate (SSDH) single crystals grown by conventional slow evaporation and Sankaranarayanan–Ramasamy (SR) method and its comparativecharacterization analysis, Materials Chemistry and Physics 132 (2012) 1019– 1028. org/10.1016/j.materresbull.2011.11.052 [14] K. Senthil et.al Synthesis, growth, structural and HOMO and LUMO, MEP analysis of a new stilbazolium derivative crystal: A enhanced third-order NLO properties with a high laser-induced damage threshold for NLO applications, Optical Materials 46 (2015) 565–577. doi.org/10.1016/j.optmat.2015.05.029 Cite the paper S. Noormohammad Shareef, K Chidambaram, S. Kalainathan, (2017). Growth and Characterization of a Nonlinear Optical Crystal a Complex Orthonitroaniline with Picric Acid Single Crystal by Vertical Bridgman Technique. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.39.72.787

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Studies of Crystal Growth, Structural and Optical Properties of Glycinium-3Carboxy-4-Hydroxybenzenesulfonate Single Crystal10 A. Thirunavukkarsu1,3, T. Sujatha1, P.R. Umarani2,3, A. Chitra1, R. Mohan Kumar3, a 1 – Department of Physics, S.I.V.E.T College, Chennai, India 2 – Directorate of Collegiate Education, Chennai, India 3 – Department of Physics, Presidency College, Chennai, India a – mohan66@hotmail.com DOI 10.2412/mmse.10.32.342 provided by Seo4U.link

Keywords: Z-scan technique, single crystal, organic compounds, thermal studies, X-ray diffraction.

ABSTRACT. Glycinium-3-carboxy-4-hydroxybenzenesulfonate (GCHBS),a new organic compound was synthesized and optical quality single crystal was grown by slow evaporation technique. The structure of grown crystal was elucidated by using single crystal X-ray Diffraction studies. The degree of sharpness and crystallinity was found from the Bragg peaks diffraction pattern. The presence of functional groups was confirmed fromthe FT-IRspectral analysis. UV–Vis transmission studies show that the grown crystal has optical transparency around 70%.The emission spectrum indicates that the GCHBS exhibits blue lighting emission sharply at 445 nm and it will be useful for fabricatingblue light emitting diodes.The thermal stability of grown crystal was studied from thermogravimetric and differential thermal analyses and found that the crystal is stable up to 235oC. The nonlinear absorption coefficient (β), nonlinear optical susceptibility (χ (3)) and nonlinear refractive index (n2) of GCHBS crystal were estimated by Z-scan technique.

Intruduction. Nonlinear optical (NLO) materials are found to havegreat interest in the recent years, because of their potential numerous optoelectronic applications. In the present modern technology, much more effort has been made to find the new second and third order nonlinear optical materials for several nonlinear optical applications such as third harmonic generation (THG), frequency mixing, electro-optic modulation and optical parametric oscillation. This technology is continuing to grow and refinement in the development of lasers crystals and higher nonlinear optical materials resulted in a variety of commercially available nonlinear optical devices. Many investigations are being carried out to synthesize new materials with large third-order optical nonlinearities in order to satisfy day-to-day technological demands [1].The presence of benzenesulfonate and hydroxyl functional groups play a vital role in nonlinearity of the GCHBS crystal and glycine is the simplest amino acid, it forms several new compounds with other organic as well as inorganic materials. Adequately, several complexes of glycine have been reported, viz., glycine picrate [2], diglycine picrate [3], glycine glutaric acid [4], etc. However, there is no report available so far on compounds of glycine with 3-carboxy-4-hydroxybenzenesulfonic acid. Hence, in the present work, the synthesis, crystal growth, structure, opticaland thermal properties of the new organic material of Glycinium-3carboxy-4-hydroxybenzenesulfonate have been reported for the first time. Materials and methods. GCHBS compound was synthesized due to the chemical reaction between the commercially available glycine and 3-carboxy-4-hydroxybenzenesulfonic acid taken in the stoichiometric ratio 1:1. The calculated amount of salts was dissolved in double distilled water. The reaction schemeand photograph of the grown single crystal of GCHBS are shown in Fig.1. The quality of single crystal depends on the purity of the used materials. Hence, the synthesized © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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compound was recrystallized several times to obtain highly purified material. The saturated solution was prepared at room temperature (32ºC), and it was stirred for more than 10 h to attain homogeneity of solution. Then, the prepared solution was filtered by using Whatman filter paper and covered with a good quality perforated polythene cover to restrict the fast evaporation of the solvent. The defectfree, optically clear, and perfectly shaped tiny crystal was chosen as seed for the growth experiment. After a span of 25days, a bulk size (13mm×6mm×6mm) GCHBS crystal was harvestedby slow evaporation method. Experimental. The grown GCHBS crystal was subjected to various characterization studies. A Bruker Kappa Apex II single crystal X-ray diffractometer with MoKα(λ=0.71013 Ǻ) radiation was used to measure cell parameters of GCHBS crystal with typical cell dimension of 0.36x0.32x0.30 mm3. Powder X-ray diffraction pattern of the grown crystal was recorded by using BRUKER AXS CAD 4 with CuKα radiation (1.5406 Å). The crystal data were obtained over a 2θ range 10-70º using step scan of 0.04º. The vibrational spectrum was performed for GCHBS compound by using FTIR– 4100 type spectrometer at a resolution of 4cm-1 in the range 400-4000 cm-1. UV-Vis transmission spectrum of GCHBS crystal was recorded in the range 190-1100nm by using LABINDIA T90+ UVVis spectrophotometer. TG-DTA experiments were carried out using a NETZSCH STA 409 instrument with a heating rate of 10ºC/min starting from 30 to 500ºC. The Z-scan technique was employed to determine third-order nonlinearity of grown crystal by using 632.8 nm He-Ne laser source.

Fig. 1. (a)Synthesis scheme and (b) Photograph of GCHBS crystal. Results and Discussions X-ray diffraction studies.The crystalline parameters of GCHBS single crystal was studied from single crystal X-ray diffraction analysis.The XRD data shows that the GCHBS crystal belongs to the monoclinic system with space group P21/c. The calculated lattice parameter values are a= 5.3651(3) Ǻ, b = 24.72079(15) Ǻ, c = 8.6840(5) Ǻ, β= 90.170(2)º, volume V = 1151.75(12) Ǻ3and Z= 4[5]. In the title salt, C2H6NO2+.C7H5O6S_, the dihedral angle between the carboxylic acid group and thebenzene ring is 5.02 (12)º. In the crystal, the anions are linked into inversion dimmers through pairs of O—H…O hydrogen bonds between the carboxylic acid groups and sulfonate O atoms. A pair of C—H…O interactions is also observed within each dimer. The anion dimers and the cations are linked into a three dimensional network by N—H…O, O—H…O and C—H…O hydrogen bonds. The crystal structure is exhibited with weak intermolecular π-π interactions and packing of the molecules in the unit cell, viewed down the a-axis.Powder X-ray diffraction studies were carried out to demonstrate the crystalline nature of the grown crystal. X-ray powder pattern of GCHBS is shown in Fig.2.The sharpness of defined Bragg peaks in the powder X-ray diffraction pattern confirmed its crystallinity. The prominent Bragg peaks in the powder MMSE Journal. Open Access www.mmse.xyz

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X-ray diffraction pattern were indexed and the peak corresponding to (102) plane has maximum countsat 2θ value of 26.29. FT-IR spectral analysis. Infrared spectrum is an exclusive physical tool for finding functional groups of the molecular structure. FTIR spectrum of GCHBS was recorded at room temperature and shown in Fig. 3. Two important features of IR spectrum of carboxylic acids are, strong H-bonding between the carboxylic acid molecules and stretching of carbonyl groups of carboxylic acids. In the present study, the above absorptions observed in the region 3500-3000 cm-1. The band observed at 3255cm−1 is due to the O-H stretching vibration, it showed the presence of amino acid substituted 3carboxy-4-hydroxybenzenesulfonic acid. A broad strong NH3+ stretching band observed in the region between 3164 and 2564cm−1 is due to amino group of GCHBS. The bands observed at 1588 and 1435 cm−1correspond to asymmetric and symmetric stretchings of amino group.The band observed at 1682cm−1is assigned to the carboxylate (COO-) symmetric stretching. The peak observed at 1747cm−1 correspond to the C=O stretching of the carbonyl group. The band examined at 1164cm−1 indicates the presence of sulfonate group (SO3). Based on FT-IR results, the formation ofGlycinium3-carboxy-4-hydroxybenzenesulfonate has been confirmed.

Fig. 2. Powder XRD pattern of GCHBS crystal

Fig.3FT-IR spectrum of GCHBS.

UV-Vis Spectral Studies. The characteristic absorption was observed at 335nm leading to electronic excitation, and there was no absorption band observed between 350 to 900 nm.The UV–Vis–NIR transmission spectrum of GCHBS is shown in Fig.4. From the transmittance UV spectrum analysis, it is clear that the grown crystal exhibit good transparency of about 70% in the visible region with lower cut-off wavelength of 335 nm. The optical band gap (E g) was evaluated from the transmission spectrum and the optical absorption coefficient (α) near the absorption edge was estimated by using the relation, (αhν) = A ( Eg – hν)1/2

(1)

where A is a constant, Eg is the optical band gap. The Tauc’s graph [6] plotted between the product of absorption coefficient and the incident photon energy (αhν)2 with the photon energy (hν) shows a linear behavior that can be considered as evidence for the direct transition (Fig. 5). The band gap value has been obtained by extrapolating the linear portion of the plot to intercept the photon energy axis andfound to be 3.67eV.The wide optical energy band gap of the grown crystal confirms that the GCHBS crystal possess large transmittance in the visible region. The refractive index of an optical material can be calculated by using transmission MMSE Journal. Open Access www.mmse.xyz

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spectrum and the reflectance of the crystal may be described in terms of absorption coefficient (Îą) obtained from the relation,

â&#x2C6;&#x2019;(đ?&#x2018;&#x2026; + 1) Âą 2â&#x2C6;&#x161;đ?&#x2018;&#x2026;

(2)

đ?&#x2018;&#x2026;â&#x2C6;&#x2019;1

The refractive index n of GCHBS crystal was found to be 2.50. This behavior is well suitable for optical device applications. Thermal analysis. The differential thermogravimetric trace of GCHBS crystal isshown in Fig.6. TGA curve shows that, no weight loss observed up to 235ÂşC. This indicates that there is no inclusion of water in the crystal lattice, which is used as the solvent for crystallization. The major weight loss started at 235ÂşC and it continued up to 290ÂşC due to the decomposition of functional groups of molecules which were evaporated for before melting point. The residual mass of 1.72% which was left out in the crucible may be carbon mass present after the decomposition process. The nature of weight loss indicated the decomposition stage of the material. However, no weight loss has been observed before this temperature. In the DTA, there is a strong endothermic peak observed at 225ÂşC. This sharp peak at 225ÂşC confirmed the melting of the compound. Photoluminescence studies. Fluorescence studies inferred the broad applications in biochemical, medical and chemical research fields for analyzing organic compounds. It generally occurs in compounds containing aromatic functional groups with low energy n-Ď&#x20AC;* transition levels.The GCHBS crystal sample was excited at the wavelength of 335 nm chosen from UV-Visible study and it was used to record the PL spectrum of the crystal in the range 300â&#x20AC;&#x201C;650 nm (Fig.7). The emission spectrum indicated the blue band emission at 445 nm and its wide optical rangeobserved from 387 to 530nm.The broadening of emission band is due to the intermolecular interactions of GCHBS crystal.

Fig. 5. Plot of (ÎąhÎ˝) 2vs. photon energy (hÎ˝).

Fig. 4. UV-Vistransmissionspectrum of GCHBS

Fig. 6. TG/DTA thermograms of GCHBS.

Fig. 7. PL spectrum of GCHBS.

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Z-Scan Measurement. The Z-scan study is used to examine the nonlinear optical properties andnonlinear absorption coefficient (β) and nonlinear refractive index (n2) of the grown crystal have been estimated. The Z-scan curves traced in open and closed aperture modes are shown in Fig.8. From the Z-scan data, the difference between the valley and peak transmittances (∆T v-p) was evaluated in terms of on-axis phase shift at the focus.

Tv p  0.4061  S 

0.25

 o

(3)

where S is the linear transmittance aperture.   2ra2   S  1  exp  2    a 

(4)

where ra is the radius of aperture and ωa is the beam radius at the aperture. The nonlinear refractive index (n2) was calculated using closed aperture Z-scan data [7, 8].

n2 

 o KI o Leff

(5)

The nonlinear absorption coefficient (β) was estimated from the open aperture Z-scan data.

 

2 2T I o Leff

(6)

The third order nonlinear optical susceptibility was calculated using the relation [9],

 3  

Re      Im     3

(7)

Table 1. Optical parameters of GCHBS measured in Z-scan experiment. Effective thickness (Leff)

0.9974 mm

Nonlinear refractive index (n2)

0.548 ×10−10cm2/W

Nonlinear absorption coefficient ()

1.6849 ×10−3 cm/W

Third-order nonlinear optical susceptibility ((3))

1.3454×10−10esu

The measured third order nonlinear optical parameters are given in Table 1. The third-order nonlinear optical susceptibility of GCHBS crystal formed by anions linked into inversion dimers through the pairs of O—H…O hydrogen bonds between the carboxylic acid groups and sulfonate MMSE Journal. Open Access www.mmse.xyz

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O-atoms to modify the second order as well as third order nonlinear optical properties. The Z-scan method confirms that the GCHBS crystal can be a promising NLO material for optical device applications such as optical modulators, optical limiters.

Fig. 8. Z-scan traces observed in (a) Open aperture and (b)closed aperture modes for GCHBS crystal. Summary. Third-order nonlinear optical GCHBS organic single crystal with 13x 6x6 mm3 dimension was grown by slow evaporation technique. From the single crystal X-ray diffraction study, it was observed that GCHBS crystal belongs to monoclinic system with P2 1/c space group. The quality of the grown crystal was ascertained by using single and powder XRD analyses and found fairly good crystalline perfection. Infrared spectral study was used to confirm the functional groups present in GCHBS compound. TG-DTA thermal study reveals that grown crystal is thermally stable up to 235oC. UV–visible study showed the good transmission region (350–900 nm) in the grown crystal. The cut-off wavelength and band gap energy were found to be 335 nm and 3.67 eV respectively. The nonlinear optical refractive index, nonlinear absorption coefficient and third-order nonlinear optical susceptibility were evaluated by using Z-scan studies. References [1] U. Meir, M. Bosch, C. Boshard and P.Gunter, DAST a high optical nonlinearity organic crystal, Synth. Met. 109 (2000) 19-22, DOI: 10.1016/S0379-6779(99)00190-3 [2] T. Devi, N. Lawrence, R. Babu, K. Ramamurthi and G. Bhagavannarayana, "Structural, Electrical and Optical Characterization Studies on Glycine Picrate Single Crystal: A Third Order Nonlinear Optical Material," Journal of Minerals and Materials Characterization and Engineering, 8 (2009) 755-763, DOI: 10.4236/jmmce.2010.95035 [3] M. Shakir, S.K. Kushwaha, K.K. Maurya, M. Arora, G. Bhagavannarayana, Growth and characterization of diglycine picrate—Remarkable second-harmonic generation in centrosymmetric crystal, J. Cryst.Growth, 311 (2009) 3871–3875,DOI: 10.1016/j.jcrysgro.2009.06.007 [4] B. Riscob, M. Shakir,J.K. Sundar, S. Natarajan, M.A. Wahab, G. Bhagavannarayana, Synthesis, growth, crystal structure and characterization of a new organic material: Glycine glutaric acid, SpectrochimicaActaA, 78 (2011) 543–548,DOI: 10.1016/j.saa.2010.11.026 [5] A.Thirunavukkarasu, A.Silambarasan, R.M. Kumar, P.R. Umarani, G.Chakkaravarthi, Glycinium 3-carboxy-4-hydroxybenzenesulfonate, Acta Crystallogr. E70 (2014) o397,DOI: 10.1107/S1600536814004590 [6] M.A. Gaffar, A. Abu El-Fadl, S.Bin Anooz, Influence of strontium doping on the indirect band gap and optical constants of ammonium zinc chloride crystals, Physica B 327 (2003) 43–54,DOI: 10.1016/S0921-4526(02)01700-3

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[7] R. Sureka, P. Sagayaraj, K.Ambujam, Third order nonlinear optical, luminescence and electrical properties of bis-glycine hydrobromide single crystals, Opt. Mater. 36 (2014) 945-949, DOI: 10.1016/j.optmat.2013.12.042 [8] G. AnandhaBabu, and P. Ramasamy, Growth and characterization of 2-amino-4-picolinium toluene sulfonate single crystal, Spectrochimica. ActaA, 82 (2011) 521–526,DOI: 10.1016/j.saa.2011.08.003 [9] A. Subashini, R. Kumaravel, S. Leela, H.S. Evans, D. Sastikumar, K.Ramamurthi, Growth and characterization of 4-bromo-4'chloro benzylidene aniline: a third order nonlinear optical material, SpectrochimicaActaA, 78 (2011) 935– 941,DOI: 10.1016/j.saa.2010.11.041 Cite the paper A. Thirunavukkarsu, T. Sujatha, P.R. Umarani, A. Chitra, R. Mohan Kumar, (2017). Studies of Crystal Growth, Structural and Optical Properties of Glycinium-3-Carboxy-4-Hydroxybenzenesulfonate Single Crystal. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.10.32.342

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Growth and Characterization of L-Glycinium Phosphate: A Promising Crystal for Opto – Electronics Applications 11 K. Rajesh1, A. Mani2,3, P. Praveen Kumar2 1 – Department of Physics, AMET University, 135, ECR Kanathur, Inida 2 – Department of Physics, Presidency College, Chennai, India 3 – Sri Venkateswaraa College of Technology, Sriperumbudur, India DOI 10.2412/mmse.18.52.862 provided by Seo4U.link

Keywords: NLO, mechanical, dielectric, LDT, Vicker’s hardness, phosphate. ABSTRACT. An amino acid based semiorganic nonlinear optical single crystal of L-Glycinium Phosphate (GLP) was grown by the slow solvent evaporation method at room temperature. The single-crystal XRD analysis shows that the grown crystals have a monoclinic structure. Fourier transforms infrared (FTIR) spectral analysis and UV–Vis spectral studies were also carried out. Microhardness mechanical studies show that the hardness number of a GLP single crystal decreases with the load as measured by the Vickers microhardness method. The dielectric properties of the grown crystal were analyzed by varying the applied frequency. The nonlinear optical properties were studied using the Kurtz and Perry powder method and the second harmonic generation efficiency was found to be 3 times higher than that of KDP crystals. Laser Damage threshold studies was carried out and ability of the crystal against intense laser beam was calculated.

Introduction: There are many potential practical applications for nonlinear optical single crystal in the field of opto electronics and photonics [1]. For optical switching materials having large nonlinearity is essential. But it is very difficult to find materials with large nonlinearities with lesser losses [2]. Organic materials are interesting candidates for nonlinear optical applications like optical switching and optical limiting [3]. Organic materials posses a conjugated system caused by nonlinear polarization that occurs because of the interaction of laser light with strong electromagnetic waves [4]. In this respect, organic amino acid crystals are the potential candidates for optical applications. Most of the amino acids are available in natural organic materials [5]. Semi organic materials which are derived from the combination of organic and inorganic materials are plays a major role in SHG and third order nonlinear optical application [6]. For finding a better NLO material, several attempts are made on many amino acids, particularly, L-Serine and L-Arginine [7, 8]. Among all these semiorganic crystals, l-Glycine is an interesting material from both the crystal engineering and supramolecular point of views. The L-Glycine gives much attention because it has higher secondharmonic generation efficiency than other organic crystals and KDP [9]. This present investigation is made on L-glycine Phosphate a new semiorganic NLO material. Various properties of the crystal like electrical, mechanical, surface threshold and SHG are discussed. Crystal Growth and synthesis.Glycinium Phosphate single crystal was grown in aqueous solution of L- glycine and ortho phosphoric acid in ratio of 1:1 at room temperature. The solution was continuously stirred for 9 hours with the help of hot magnetic plate. The solubility of glycinium phosphate in water was gravimetrically analyzed and the solubility found to be increase with increase in temperature. The saturated solution then filtered and was allowed for complete evaporation at room temperature for few days. Seed crystals were obtained in a period of 13 days. The crystalline quality of the seed crystal was improved by successive recrystallization process. Optically transparently and © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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good quality bulk crystal was obtained after a period of 2 weeks days from the day of recrystallization process. The grown crystal with dimension of 12 × 12 × 2 mm3 was taken for further studies and is shown in Fig. 1.

Fig. 1. Photograph of as grown GLP crystal. Result and discussions Single crystal X-ray diffraction study.Single crystal X-ray diffraction study was carried out for finding the cell parameters and crystal structure of glycinium phosphate crystal using Enraf Nonius CAD-4/MACH 3 diffractometer, with MoKα. The glycinium phosphate crystal is belonging to monoclinic crystal system with the space group P21. Cell parameters and space group of the grown crystal found from single XRD are in good agreement with the reported value [10] and are shown in table 1. Table 1. XRD data of GLP crystal. Cell Parameters Present work Reported Values a

9.619 Å

8.467 Å

7.621 Å

7.411(2)

Crystal system

monoclinic

α= γ

90°

100.11

100.43(2)

Space group

P21

9.7920(10) 8.4870(10)

FT-IR Study .In order to confirm functional groups present in GLP crystal, fourier transform infrared (FTIR) spectrum was recorded in the range 400–4000 cm-1 using the Perkin Elmer Infrared spectrophotometer. L-Glycine Phosphate single crystal was powdered and made as pellet shaped and subjected to FT-IR analysis. The absorption peaks are observed in between 400 to 4000 cm-1 and it is shown in figure.3. The very strong absorption peak at 3400 cm-1 indicates the presence of primary amine in the grown crystal. NH2 plane deformation of primary amine is observed at the absorption peaks 1594 cm-1 and 1666 cm-1. The P-O stretching frequency and deformation of Phosphate ion were MMSE Journal. Open Access www.mmse.xyz

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identified at the peaks 1113 cm-1 and 500 cm-1 respectively [11]. This confirms the presence of phosphate ion in the grown crystal lattice. UV-Visible analysis.From the transparency window of the material one can easily find out the usefulness of the crystal in linear and nonlinear applications. The optical absorption spectrum of GLP crystal was recorded in the wavelength region 190 nm to 1500 nm and is shown in Fig. 4. The lower cutoff wavelength of the grown GLP crystal is found to be 224 nm. Less absorption was found in the visible region and the crystal has the superior transmittance in the entire UV-Vis spectrum. The absence of strong absorption in the entire visible range and good transmittance suggests that the grown GLP crystal is a useful material for the SHG applications [12]. Hence it is concluded that the grown crystal can be used for optoelectronic applications. The energy gap (Eg) of the grown GLP crystal was calculated as 2.26 eV.

Fig. 3. FT-IR spectrum of GLP Crystal.

Fig. 4. UV-Vis spectrum of GLP. Laser Damage threshold study.The Laser Damage Threshold (LDT) of a crystal is an important factor affecting its optical applications. It depends on the material specific heat, thermal conductivity of the crystal and optical absorption of the crystal. LDT measurement of the GLP crystal has been carried out using a Q-witched Nd:YAG Laser beam of wavelength 1.064 Îźm with the pulse width rate of 10 ns. The repetition rate of the measurement is 10 Hz. The Laser beam of focal length 0.5 mm is focused on the sample area of 0.7 mm. The LDT value of the grown crystal obtained from single shot method is found to be 4.27 GW/cm2. Second Harmonic Efficiency.The Nonlinear optical property of the grown crystal is studied by Kurtz-Perry powder technique [23]. The standard KDP crystal has been used as the reference material for the grown crystal. The input energy of the laser source was 5 mJ/pulse. The SHG output wave at 532 nm was collected by the mirror, collimated and focused on to an photomultiplier for detection. The output SHG signal of 59.4 mV was obtained from the GLP crystal, whereas, the KDP crystal MMSE Journal. Open Access www.mmse.xyz

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

gave an output of 21.4 mV for the same input signal. Thus it is evident that the SHG efficiency of the Glycinium Phosphate crystal is almost 3 times that the KDP crystal and the crystal is suitable for device fabrication. Dielectric measurement.Single crystals of GLP was subjected to dielectric measurements, A thin coating of graphite applied on both sides of the crystal to provide necessary electrical conductivity. The capacitance of the crystal was noted at different temperatures using applied frequencies varying from 50 kHz to 5 MHz. Fig.6. shows the dielectric constant as a function of log frequency varying with temperature. The dielectric constant initially decreases with the increasing frequency, and at low temperatures of 313 K and 323 K, the dielectric constant (εr) has a higher value then the higher temperature 343 K and 353 K. The magnitude of εr depends significantly on the degree of polarization and charge displacement of the grown crystal. The low dielectric loss in higher frequency range shows (fig.7) that the grown crystal has few defects. The variations in the dielectric constant and dielectric loss as functions of frequency for GLP crystal may be considered as a normal behaviour of dielectrics and it shows that the crystal posses some minimum defects, which will be useful in device fabrication [13].

0.7

0.6 0.6

0.5

313K 323K 333K 343K 353K

0.4

0.3

313K 323K 333K 343K 353K

0.4

Dielectric loss

Dielectric constant

0.5

0.2

0.3

0.2

0.1

0.0

0.0 2

Log f

Fig. 5. dielectric constant vers log f .

Fig. 6. Dielectric loss vers log f.

Microhardness study.The micro hardness test were carried out with the load range from 5 to 50 g using the Vickers hardness tester Richert MD 4000E ultra fitted with a diamond pyramidal indenter. The indentations were made at room temperature with a constant indentation time of 10 s.

Fig. 8. Mayer’s graph.

Fig. 7. Hardness plot of GLP.

As micro cracks were observed at higher loads the maximum applied load was restricted to 40 g. The lower load is due to the poor compaction [14] and highly brittle nature of the GLP crystal, that they undergo severe cracking and fracture for higher loads. The root cause of fracture is on the basis of molecular packing and attachment energies in the crystal structure [15]. The Meyer’s index number was calculated from the Meyer’s law, which relates the load.

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P = Kdn

(1)

where K is the material constant and n is the Meyer’s Index. Fig. 8 shows the plot of mayer’s, yields straight line graph (before cracking plastic deformation) which is in good agreement with Meyer’s law. The obtained slope value n is 1.97 for (110) plane by using the method of least square fitting. According to Onitsch [16], the value of n for soft materials is above 1.6. In this case proves GLP belongs to soft organic material category. Summary. Organic nonlinear optical single crystal of Glycinium Phosphate was successfully grown by slow evaporation technique used water as a solvent. Single crystal X-ray diffraction study confirmed that the grown crystal belongs to monoclinic crystal system with the space group P21.Various functional groups were presented in the crystal was confirmed by Fourier transform infra red spectrum. The superior transmittance of the crystal in the entire visible region suggests that the GLP crystal is suitable for second order nonlinear optical applications. The hardness of the material indicates that the material belongs to soft material category which is the important property of the NLO material. This implies that GLP single crystal is a good engineering material for device fabrications. The Laser Damage Threshold value of the grown crystal is found to be 4.27 GW/cm2. Both dielectric constant and loss are decreases with increase in frequency will prove that the GLP crystal posses minimum defects. The NLO efficiency of the Grown GLP crystal is 3 times of that the KDP crystal and the crystal is suitable for opto –electronics device applications. References [1] Rajesh,K. Arun,A. Mani,A. Praveen Kumar, P. (2016). Crystal growth, perfection, linear and nonlinear optical, photoconductivity, dielectric, thermal and laser damage threshold properties of 4methylimidazolium picrate: an interesting organic crystal for photonic and optoelectronic devices. Mater. Res. Express, 3, 106203, doi: /10.1088/2053-1591/3/10/106203 [2] Gaetano Assanto, George Stegeman, Mansoor SheikBahae, and Eric Van Stryland, (1993), All optical switching devices based on large nonlinear phase shifts from second harmonic generation, Appl. Phys. Lett. 62, 1323; doi: 10.1063/1.109611. [3] A.a. Said-C. Wamsley-D.j. Hagan-E.w. Stryland-Bruce Reinhardt-Paul Roderer-Ann Dillard – (1994), Chemical Physics Letters, 228, 646-650. Doi: 10.1016/0009-2614(94)00999-6 [4] T. Verbiest, S. Houbrechts, M. Kauranen, K. Clays, A. Persoons, Second-order nonlinear optical materials: recent advances in chromophore design, J. Mater. Chem. 7 (1997), 2175–2189.doi: 10.1039/a703434b [5] P. Baskaran a, M. Vimalan b, P. Anandan d, G. Bakiyaraj c, K. Kirubavathi a,K. Selvaraju, Synthesis, growth and characterization of a nonlinear optical crystal:l-Leucinium perchlorate, Journal of Taibah University for Science xxx (2016) xxx–xxx.doi: 10.1016/j.jtusci.2016.03.003 [6] M. Esthaku Peter, P. Ramasamy, Growth, thermal, dielectric and mechanical studies of tri glycine zinc chloride, a semiorganic nonlinear optical material, Mater. Lett. 64 (2010) 1–3. Doi: 10.1016/j.matlet.2009.08.048 [7] Structural, Linear, and Nonlinear Optical and Mechanical Properties of New Organic L-Serine Crystal, K. Rajesh and P. Praveen Kumar, Journal of Materials, Volume 2014 (2014), Article ID 790957, 5 pages, doi: 10.1155/2014/790957 [8] D. Eimerl, S. Velsko, L. Davis, F. Wang, G. Loiacona, G. Kennedy,Deuterated l-arginine phosphate: a new efficient nonlinear crystal, IEEE J. Quant. Electron. QE-25 (1989) 179–193. Doi: 10.1109/3.16261

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[9] M. Lenin, M. Chandrasekar, G. Udhayakumar, (2014), Growth and characterization of nonlinear optical single crystal: Glycine zinc sulfate, International Journal of ChemTech Research, Vol.6, No.5, pp 2683-2688. [10] M.-T. Averbuch-Pouchot, Structures of glycinium phosphite and glycylglycinium phosphite, Acta Cryst. (1993). C49, 815-818, doi: 10.1107/S0108270192010771 [11]. K. Rajesh, A. Mani, V. Thayanithi, and P. Praveen Kumar, Optical, Thermal, and Mechanical Properties of L-Serine Phosphate, a Semiorganic Enhanced NLO Single Crystal, International Journal of Optics, Volume 2016 (2016), Article ID 9070714, 5 pages, doi: 10.1155/2016/9070714 [12] Dana W. Mayo, Foil A. Miller, Robert W. Hannah, Course Notes On The Interpretation Of Infrared And Raman Spectra, (John Wiley & Sons, Inc., Hoboken, New Jersey), 2003. [13] G.P. Smyth, New York, 1955.

Dielectric

Behavior

and

Structure,

McGraw-Hill,

[14] C. Thompson, M.C. Davies, C.J. Roberts, S.J.B. Tendler, M.C. Wilkinson, (2004), The effects of additives on the growth and morphology of paracetamol (acetaminophen) crystals, Int. J. Pharm. 280, 137- 150. Doi : 10.1016/j.ijpharm.2004.05.010 [15] E.V. Boldyreva, T.P. Shakhtshneider, M.A. Vasilchenko, H. Ahsbahs, H. Uchtmann, ActaCryst. Section B Struct. Science 56.2 (2000), 299-309. Doi : 10.1107/s0108768199013634 [16] E.M. Onitsch, Micro – hardness testing, Mikroskopie, 1947, 2, 131. Cite the paper K. Rajesh, A. Mani, P. Praveen kumar, (2017). Growth and Characterization of L-Glycinium Phosphate: A Promising Crystal for Opto – Electronics Applications. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.18.52.862

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Growth and Characterization of Organo-metallic Single Crystals of (HCLPTM) Heptachloro (L-Proline) TetraMercury (II)12 V. Revathi Ambika1, D.Shalini1, R. Usha1, N. Hema1, D. Jayalakshmi1,a 1 – PG & Research Department of Physics, Queen Mary’s College, Chennai -600 004, India

a – djayalakshmi2016@gmail.com DOI 10.2412/mmse.42.99.188 provided by Seo4U.link

Keywords: Solution growth, Single XRD, UV, FTIR, microhardness, NLO.

ABSTRACT. A new promising organo-metallic nonlinear optical material, was synthesized and single crystals of HCLPTM were grown from solution by slow evaporation technique. Single-crystal X-ray diffractometer was utilized to measure unit cell parameters and to confirm lattice parameter. The optical transmittance window and the lower cutoff wavelength of the HCLPTM have been identified by UV–Vis–NIR studies. The modes of vibration of different molecular groups present in the sample were identified by the FTIR spectral analysis. The mechanical strength of the crystal was analyzed by Vickers hardness test. The second harmonic generation (SHG) efficiency was estimated using the modified Kurtz–Perry powder test and was found to be 2.5 times that of KDP.

Introduction. Amino acids are the building blocks of proteins that are considered to be the very important for most of the processes in living organisms [1] and their complexes belong to a class of organic materials find immense nonlinear optical (NLO) applications [2].The presence of acidic carboxyl and basic amino group paves the way for the formation of zwitter ion or dipolar ion as a result of internal neutralization reaction. This dipolar nature of amino acids helps to improve the crystal’s hardness [3] and the physical and chemical properties also making them as a peculiar candidates in nonlinear optical field [4]. The organic materials have excellent properties compared to the conventional inorganic solids which show ultrafast response times, lower dielectric constants, better process ability characteristics and enhanced NLO responses [5]. But the practical applications of the organic nonlinear optical materials are limited because of their poor physicochemical stability and low mechanical strength [6]. For overcoming the above difficulties of the organic NLO crystals, in recent years the organic materials were mixed with inorganic materials to improve their chemical stability, physico-chemical properties, mechanical strength and nonlinear optical coefficients, which are the important parameters for an NLO crystal [7,8]. According to Dewar–Chatt–Duncanson model, the binding between metal and ligand is due to the interplay of donor and acceptor contributions [9]. Yukawa et al.[10] have already reported the structure of heptachloro(l-proline)tetramercury(II) and it belongs to monoclinic crystal system . In the present work we report synthesis,crystal growth, spectral, optical, and dielectric properties of metal coordinated complex of HCLPTM. The asymmetric unit of the title compound, [Hg4Cl8-(C5H9NO2)2]n, consists of four HgCl2 units and two L-prolineligands in the zwitterionic form. In each HgCl2 unit, the HgIIion is strongly bonded to two Cl atoms, and the HgII ions intwo of the HgCl2 units are chelated by O atoms of twol-proline ligands, with one strong and one weak Hg—O bond.In the crystal structure, HgCl2 and L-proline units are linkedto form an extended chain along the a-axis. The chain structureis further stabilized by N—H….Cl hydrogen bonds, and thechains are arranged in layers parallel to the ab plane.

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Thestructure of the title compound was originally determined byEhsan, Malik & Haider [(1996). J. Banglad. Acad. Sci. 20, 175]but no three-dimensional coordinates are available. Experimental Procedure Material Synthesis.The title complex crystal was grown from an aqueous solution employing the slow solvent evaporation solution growth technique at room temperature. The chemicals used for synthesis are of analytical grade and are commercially available.The starting material of L-proline and HgCl2 was taken in 1:2 stoichiometric ratio to synthesis heptachloro (l-proline) tetramercury (II). The reaction scheme is shown in Eqn.1. 2( C5H9NO2 ) + 4HgCl2

[Hg4Cl8(C5H9NO2)2]

(1)

The calculated amount of mercury chloride was first dissolved in deionized water.L-proline was then added to the solution slowly by stirring. The prepared solution was allowed to dry at room temperature and the salt was obtained by slow evaporation technique. The purity of the synthesized salt was improved by successfully recrystallization. After 25 days of growth, transparent single crystal were obtained by slow evaporation technique and grown crystals are shown in Fig. 1.

Fig.1. Photograph of the HCLPTM single crystal. Characterization Technique Single Crystal X-Ray Diffraction Studies.Single crystal X-ray diffraction study was carried out on the as grown HCLPTM single crystal. HeptaChloro(L-Proline)TetraMercury(II) crystal belongs to triclinic system .a = 7.31 ˚A, b = 9.47 ˚A, c = 10.50 ˚A, α = 108.48, β = 107.36, γ = 97.24 and volume V = 638 A3. UV Analysis.The transmittance spectrum of grown single crystal was recorded using Varian Cary 5E UV–vis–NIRspectrometer in the range of 200–900 nm. From thetransmission spectrum (Figure 2), it is observed that the maximum transparency of 88% and UV cut-off wavelength 238nm were observed for the LPDMC single crystal. The very high transmission in the entire visible and nearIR region and short cut-off wavelength facilitates it to be a potential NLO material for second harmonicfrequency doubling [11].

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100

Transmittance % T

80 60 40 20 0 100

238nm

200

300

400

500

600

700

800

900 1000

Wavelength nm.

Fig. 2. UV-transmittance spectrum of HCLPTM single crystal. FTIR Analysis.The powdered specimen of HCLPTMhas been subjected to FT-IR analysis by using PERKIN ELMER RX1 Fourier transform infra-red spectrophotometer. Using KBr pellet technique in the wavelength range between 400 and 4000 cm-1 carried out the FTIR analysis of HCLPTM. The recorded Fourier transform infra-red (FT-IR) spectrum of HCLPTM is shown in Figure 4. 70

Transmittance % T

60 50 40 30 20 10 4000

3500

3000

2500

2000

wave number

1500

1000

500

(cm-1)

Fig. 3. FTIR spectrum of HCLPTM single crystal. The transmission is due to the carboxylate group (COO -)of free proline is normally observed in the region 460.04 cm−1, 614.35 cm−1 and 1400.38 cm−1. Where as in the case of HCLPTM, these peaks were shifted to wagging and symmetric stretching respectively. Wagging of CH2 occurs at 1337.69 cm−1. The symmetricStretchingvibrations of C-H are observed at1036.78 cm−1and 1163.13 cm−1C-N symmetric stretching. The CH2 rocking vibrationmode occurs at 837.14 cm-1 and 960.59 cm−1.The low intensity sharp peaks appear at 3160.50 cm-1 and 3522.17cm-1N-H asymmetric and symmetric stretching vibrations respectively. The very small intensity peaks appear at 662.58 cm-1 C-Cl occurs. The vibrations at 1619.31 cm -1 and 2763.15 cm-1 is due to NH2 in-plane deformation. This observation confirms that proline mercuric chloride exists in the zwitterionic form and the MMSE Journal. Open Access www.mmse.xyz

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involvement of NH2 + in hydrogen bonding is evident by the fine structure of the band in the lower energy region. Microhardness Studies.Hardness is an important mechanical property required for the fabrication of electronic and optical devices. To get accurate result of hardness of the grown crystal, several indentations were made on the sample for different applied loads from 10g to 100g and mean diagonal lengths were measured. The Vickers hardness number was calculated Using the following expression [12]. Hv = (1.8544 P/d2) kg/mm2

(2)

where P is the applied load in kg and d is the average diagonal length of the indentation in mm. The hardness value of HCLPTM is found to increase with the applied load. Work hardening coefficient n, a measure of the strength of the crystal, is computed from the logp-logd plot (Fig. 4). It brings forth the fact that the HCLPTM crystals are found to have been improved in mechanical strength. The plot of logp-logd yields a straight line and its slope, and the work hardening index, n are found to 1.33. Hence it is concluded that HCLPTM belongs to hard materials.

1.8

Log D

1.6 1.4 1.2 1.0 1.0

1.1

1.2

1.3

1.4

Log

1.5

1.6

1.7

1.8

Fig. 4. Log P Vs Log D of HCLPTM. SHG Measurement. The SHG of the crystal was checked using the powder SHG technique developed by Kurtz and Perry [13] .The grown single crystal was crushed to fine powder and then packed in a micro capillary of uniform bore and exposed to laser radiations. The 532 nm radiation was collected by a monochromater after separating the 1064 nm pump beam with an infra-red blocking filter. The second harmonic radiation generated by randomly oriented micro crystals was focused by a lens and detected by a photo multiplier tube (Hamamatsu R2059). The second harmonic generation is confirmed by the emission of green light and its efficiency is found to be 2.5 times greater than that of KDP crystal. Conculsion. Single crystals of HCLPTM were successfully synthesized and the single crystals have been grown by solution growth technique. From XRD data, it is observed that the grown crystal belongs to triclinic structure. The various functional groups in HCLPTM have been identified from the Fourier transform infrared (FT-IR) analysis. The grown crystal has good transmission window in the visible region between 238 and 900 nm suitable for NLO applications. The mechanical behavior was discussed using Vickers hardness test. The SHG test confirms the second harmonic conversion MMSE Journal. Open Access www.mmse.xyz

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efficiency of the crystal and it is found to be 2.5 times better than that of potassium dihydrogen phosphate (KDP). Acknowledgement One of the authors (D.JAYALAKSHMI) is grateful to the university grants commission for financial support under minor research project scheme. References [1] M.A. Awawdeh, J. Andrew Legako, H. James Harmon, Solid-state optical detec-tion of amino acids, Sens. Actuators B 91 (2003) 227–230. [2] B. Narayana Moolya, S.M. Darmaprakash, Nonlinear optical diglycinehydrochloride: synthesis, crystal growth and structural characteristics, J. Cryst.Growth 293 (2006) 86–92. [3] C. Ramachandra Raja, G. Gokila, A. Antony Joseph, Growth and spectroscopiccharacterization of a new organic nonlinear optical crystal: l-alaninium succi-nate, Spectrochim. Acta A 72 (2009) 753–756. [4] T. Mallik, T. Kar, Growth and characterization of nonlinear optical l-argininedihydrate single crystals, J. Cryst. Growth 285 (2005) 178–182. [5] A.K. Jeewandara, K.M. Nalin de Silva, Are donor–acceptor self organized aro-matic systems NLO (non-linear optical) active? J. Mol. Struct. Theochem. 686 (2004) 131–136. [6] J. Mary Linet, S. Dinakaran, S. Mary Navis Priya, S. Jerome Das, Growth andcharacterization of pure and Hg2+doped thiosemicarbazide cadmium chloridecrystals, Cryst. Res. Technol. 44 (2009) 173–176. [7] K. Wu, C. Chen, Theoretical studies for novel non-linear optical crystals, J. Cryst.Growth 166 (1996) 533–536. [8] L. Li, Z. Wang, X. Song, S. Sun, Synthesis and characterization of a new metal-organic NLO material: dibromo bis (triphenylphosphine oxide) mercury(II),Spectrochim. Acta A 72 (2009) 816– 818. [9] W. Koch, M.C. Holthausen, A Chemist’s Guide to Density Functional Theory, 2nded., WileyVCH Verlag GmbH, 2001. [10] D. Kalaiselvi, R. Mohan Kumar and R. Jayavel, The structure of heptachloro (l-proline) tetramercury (II), Acta Crystallographica Section E(2008) 1600-5368 [11]. V. Krishnakumar, R. Nagalakshmi, Spectrochim. Acta A 61 (2005) 499. [12] D. Kalaiselvi, R. Jayavel, Appl. Phys. A107 (2012) 93–100. [13]S.K.Kurtz and T.T.Perry, J. Appl. Phys., 1968, 39, 3798. Cite the paper V. Revathi Ambika, D. Shalini, R. Usha, N. Hema, D. Jayalakshmi (2017). Growth and Characterization of Organo-metallic Single Crystals of (HCLPTM) Heptachloro (L-Proline) TetraMercury (II). Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.42.99.188

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Comparative Study of Erbium Doped KDP Single Crystals Grown by Different Techniques13 V. Roopa1, Dr. R. Ananda Kumari1 1 – Sree Siddaganga Research Center, Sree Siddaganga College of Arts, Science and Commerce for Women, Tumkur, Karnataka, India DOI 10.2412/mmse.84.25.878 provided by Seo4U.link

Keywords: crystal growth, SR method, SHG, optical properties.

ABSTRACT. Erbium doped potassium dihydrogen Orthophosphate (KDP) single crystals were grown by different techniques - SR method, Seed Rotation and Slow Evaporation with the vision to improve the properties of the crystal. The objective of this study is to show how the dopant Erbium influences the growth, morphology and characteristics of KDP crystal. The crystal size grown by SR method on unidirectional {101} pyramidal face was around 150 mm in length and 16 mm in diameter. The Chemical composition of the grown crystals is confirmed by EDAX Analysis. The grown crystals are subjected to PXRD analysis using XrdwinPD 4-dectris computer based diffractometer with a characteristic Cu Kα (1.540598) radiations from 100 to 600 at a scan rate of 100/min, confirm the crystalline nature and shifts in peak positions due to doping is observed. Using Scherer’s equation crstallite size has been calculated and the crystallite size is around 44 nm. Solubility of crystals grown by slow evaporation technique is determined using water as a solvent. The solubility curve shows that that Erbium doped KDP crystals has higher solubility than the pure KDP. The SHG efficiency is determined by Kurtz powder technique. It is found that relative SHG conversion efficiency of crystal grown by SR method is greater compared to other techniques. Optical transmission spectra are recorded for the crystals in the wavelength region 200 to 1100nm using Perkin-Elmer Lambda 35 UV-Vis spectrophotometer. It is found that percentage transmission of crystals grown by SR method is more as compared to other techniques. The electronic band transitions is studied from the plot of (αhv)2 versus photon energy (hv) and the band gap energy has been calculated. The addition of Erbium improves the quality and transparency of crystals, which shows the suitability of the ingot for optical applications.

Introduction. With the advanced research approach on efficient nonlinear optical material (NLO) is intensively studied for various optical device applications. Potassium dihydrogen orthophosphate (KDP) is a best known NLO material and has been used for second harmonic generation for high pulse energy, laser frequency conversion, low repetition (<100 Hz) rate lasers, electro-optical modulation and Q-switching applications [1-3]. As a result, significant efforts have been made to find novel and efficient NLO materials. The study of the crystallization behavior of KDP and the factors influencing its structural properties is still of great interest. The most important factor which influences the growth rate, the surface morphology of crystal is impurities [4, 5]. An impurity can suppress, enhance or stop the growth of crystal completely. Modern technical tasks like high power laser systems have a great demand for very large size crystals. The use of special additives is an effective way to accelerate the growth rate. The beneficial effect of additives on the growth process and properties of crystals has been applied in recent years [6-8]. The most efficient additives are reagents with metal ions that have the same properties as that of bulk solutions which can change the properties of solution such as viscosity, surface tension, etc. without deteriorating the optical qualities of crystals. Hence Erbium is selected as additive in the KDP solution and doped KDP crystals were grown from the aqueous solution with seed rotation, SR method and slow evaporation technique and the grown crystals are subjected to different characterizations like © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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powder X-ray diffraction, optical transmission, EDAX and second harmonic generation efficiency studies. Experimental Crystal Growth. Good quality crystals of pure and Erbium doped KDP were grown by slow evaporation technique as shown in Fig 1(c). A volume of 200ml of water was taken in a beaker and known quantity of the material was added till it attains saturation for temperatures. Sankaranarayanan-Ramasamy (SR) method was employed to grow the bulk size of Erbium doped KDP single crystals. The apparatus consists of glass container of size 30x30x30 cm3 and ampoule of inner diameter 10mm using two ring heaters. A suitable seed crystal grown by slow evaporation technique having a size of 4x4x3 mm3 with <101> direction was selected for unidirectional crystal growth. The ampoule was kept in the glass water bath to maintain constant ambient temperature. Super Saturated solution was poured carefully into the ampoule without disturbing the seed crystal. The ring heaters are positioned one at the top and another at the bottom of the growth ampoule. The growth was initiated with a suitable temperature provided by the ring heater at the top region of the saturated solution under equilibrium condition. The temperature difference between the top and bottom ring heaters of the growth ampoule was carefully maintained to control the nucleation. In the present work, the temperature around the top and bottom of the ampoule was maintained at 32 oC and 27oC respectively. Under this condition highly transparent crystal growth was seen after 10 days. After three months of the growth duration, a good quality crystal was harvested with size 140 mm in length and 16 mm in diameter as shown in Fig.1(a). Finally, the ampoule was detached from the growth system and the grown crystal was carefully removed from the ampoule using diamond glass cutter. Stirring the solution reduces the natural convection-induced temperature oscillations by homogenizing the bulk solution. Hence, the importance of optimum rates of rotation in crystal growth processes has gained recognition in the past decade [9]. The two most widely used stirring mechanisms are the rotation of the seed and/or the rotation of the crystallizer. In the present work, KDP crystals doped with Erbium were grown from aqueous solution by continuously rotating the growing crystal at 40 rpm. This apparatus consists of a seed rotation controller coupled with a stepper motor which is controlled by using a microcontroller based drive. This controller rotates the seed holder in the crystallizer. The seed crystals mounted on the center of the platform made up of acrylic material and is fixed into the crystallizer. The seed mount platform mix the solution very well and makes the solution more stable, which resulted in better crystal quality.The aqueous solutions at the saturation temperature 40oC was filtered in a closed system to remove extraneous solid and colloidal particles. Then the solution was overheated at 50 oc for one day, to make the solution stable against spontaneous nucleation under a high supersaturation [10]. After overheating, the temperature of the solution was reduced slightly above the saturation point and seed crystals were mounted on the platform. From the saturation point, the temperature was decreased at 0.1oC per day at the beginning of the growth. As the growth of the crystal progressed, the temperature rate was decreased. After reaching the room temperature, crystals was harvested. The grown crystals are shown in Fig.1(b).

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Fig. 1. (a).Photograph of Erbium -doped KDP crystals grown by SR method.

Fig. 1. (b). Photograph of Erbium -doped KDP crystals grown bySeed Rotation technique.

Results and discussion Determination of Solubility. The Solubility studies were carried out in a constant temperature water bath (CTB). The Solution was stirred continuously for 6 hours to achieve stabilization using an immersible magnetic stirrer. Solubility was determined by gravimetric analysis for different temperatures (25-500C). The Solubility curve of pure KDP & Erbium doped KDP crystals grown by slow evaporation technique is shown in Fig.2. It is observed from the solubility curve that the solubility of KDP doped Erbium decreases with increase in the molar weight of KDP and has positive temperature co-efficient.

Pure KDP KDP doped Erbium (Slow Evaporation)

Concentration in g/100ml of water

38 36 34 32 30 28 26 24 22 20 25

Temperature in C

Fig. 1. (c). Photograph of Erbium -doped KDP.

Fig. 2. Solubility Curve of the grown crystals crystals grown by Slow Evaporation method.

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EDAX Analysis

Table 1. Shows the estimated Weight % of KDP doped Erbium Crystal (Slow Evaporation method).

Fig 3. EDAX Spectrum of KDP doped Erbium crystal (Slow Evaporation method).

Element

Weight %

Atom %

1.52

3.49

37.19

44.27

0.51

0.53

53.04

50.00

7.74

1.70

Total

100.00

Table 2. Shows the estimated Weight % of KDP doped Erbium Crystal (Seed Rotation method).

Fig. 4. EDAX Spectrum of KDP doped Erbium crystal (Seed Rotation method).

Element

Weight %

Atom %

2.60

5.76

38.40

43.89

0.66

53.83

48.74

4.51

0.95

Total

100.00

In order to confirm the presence of the Erbium, the grown crystals was subjected to EDAX analysis. The EDAX spectra for KDP doped Erbium grown by Slow evaporation, Seed Rotation technique and SR method was recorded and analyzed. The spectrum shows the peaks of potassium, phosphate, oxygen, chlorine and Erbium suggesting that the Erbium dopant has entered into the crystal lattice of KDP. The recorded spectrum for the grown crystals are shown in Fig.3, 4 & 5. The Observed weight percentage of elements in the doped KDP crystal are given in the Table 1,2 & 3. Powder X-ray diffraction studies. Powder X-ray diffraction studies was performed on grown crystals to identify the phase formation and degree of crystal perfection. X-ray powder patterns of grown crystals was recorded using XrdwinPD 4-dectris computer based diffractometer with a characteristic Cu KÎą (1.540598) radiations from 100 to 600 at a scan rate of 100/min. The Xrd pattern of the grown crystals are shown in Fig 6. The occurrence of sharp peaks at specific bragg's angle shows the crystallinity of the grown crystals. It is clear from the pattern that the entry of the dopant in the modified composition of KDP crystal lead to a change in the intensity of peaks when compared to the peaks of pure KDP crystals. Average crystallite size (D) was estimated using the following relation (1)

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Table 3. Shows the estimated Weight % of KDP doped Erbium Crystal (SR method). Element

Weight %

Atom %

2.69

6.06

37.07

43.12

0.53

0.54

53.01

48.84

6.69

1.44

Total

100.00

Fig. 5. EDAX Spectrum of KDP doped Erbium crystal (SR method).

0.9ď Ź ď ˘ cos ď ą

Dď&#x20AC;˝

(1)

where Îť is wavelength of the X-ray radiation, Î˛ is full width at half maximum (FWHM) of diffraction peak (in rad), and Î¸ is scattering angle. Further, the dislocation density (Î´) and micro strain (Îľ) was estimated by the relation (2, 3, & 4). 1 D2

ď ¤ ď&#x20AC;˝ ď Ľď&#x20AC;˝

(2)

ď ˘ cos ď ą

SF =

(3)

2Ď&#x20AC;2 â&#x2C6;&#x161;3đ?&#x2018;Ąđ?&#x2018;&#x17D;đ?&#x2018;&#x203A;Ć&#x;

(4)

The obtained structural parameters were given in Table 3.Williamson and Hall (W-H) plots was used to estimate the micro strain in KDP doped Erbium crystal grown by different methods using the relation (5).

ď ˘ cos ď ą ď&#x20AC;˝

kď Ź ď&#x20AC;Ť 4ď Ľ sin ď ą D

(5)

where Îľ is strain associated with the crystal. Equation (5) represents a straight line between 4sinÎ¸ (X-axis) and Î˛cosÎ¸ (Y-axis). The slope of line gives the strain (Îľ) and intercept (kÎť/D) of this line on Y-axis gives grain size (D). Fig. 7. shows the W-H plots of grown crystals and the estimated strain values was shown in Table 4.

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KDP+Erbium Chliride(SR Method)

10000 5000

KDP+ErbiumChloride(Seed Rotation)

10000

Cos

Intensity in a.u

5000 0

KDP+Erbium Chliride(Slow Evaporation)

20000 15000 10000 5000 0 -5000

Pure KDP

20000 10000 0 0

0.5

1.0

2 in degree

1.5

2.0

4Sin

Fig. 6. Powder X-ray diffraction pattern of grown crystals.

Fig. 7. W-H Plot of grown crystals.

Table 4. Estimated crystallite size, strain, dislocation density and surface factor of grown crystals. Sample

Crystallite size (nm)

Strain

Stacking fault(SF)

Dislocation density δ(1014)m-2

Scherrer's formula

W-H plot

Pure KDP

44.03

64.24

8.554E-4

17.39

5.15

KDP+Er (Slow evaporation)

51.03

74.20

8.878E-4

17.40

3.84

-4

17.35

5.16

17.41

4.55

KDP+Er (SR method)

44.01

21.68

4.280E

KDP+Er (Seed Rotation)

46.83

34.43

3.829E-4

UV-Visible Transmission.Crystal plates of pure KDP and KDP doped Erbium crystals were cut and polished without any coating for optical measurements. The thickness of the crystals were around 1mm. Optical transmission spectra were recorded for the crystals in the wavelength region 200 - 1100 nm using Perkin-Elmer Lambda 35 UV-Vis spectrometer. The recorded UV-Vis spectrum is shown in the Figure 8. Good optical transmittance and lower cut off wavelength are very essential properties for nonlinear optical (NLO) crystals [11]. It is observed from the figure that the Pure KDP shows 45% of transmittance, KDP doped Erbium (Slow Evaporation method) shows 65% transmittance, KDP doped Erbium (Seed Rotation method) shows 70% of transmittance and KDP doped Erbium (SR method) shows 85% of transmittance. The large transmission in the entire visible region enables it to be a good material for electro-optic and NLO applications. The above results indicate that the addition of Erbium to pure KDP increased the transmittance. There is a non linear trend in transmittance between 400 to 800nm wavelength shows that the light is only transmitted and not absorbed in this visible region. The plot of (αhv) 2 versus photon energy hv is plotted as shown in Figure 9. In order to find the value of Eg we make use of the relation (7): α = 2.303 log (T/d)

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(7)

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where α is absorption coefficient, d is the thickness of the sample and T is the transmittance, hν is the photon energy. Plot the graph of (αhν)2 versus hν .The values of Eg have been found by taking the intercept of the curve, at which it increases linearly. The wide optical band gap of KDP is 4.7eV, KDP doped Erbium crystals is found to be 5.0eV, and 5.1eV for the grown crystals respectively suggests its suitability for optoelectronics applications.

8.00E+007

KDP+Erbium(SR method)

6.00E+007

Eg=5.1eV

4.00E+007 2.00E+007 0.00E+000

KDP+Erbium(Seed Rotation)

1.50E+008 85

1.00E+008

5.00E+007

(h)

% Transmittance

Eg=5eV

0.00E+000 1.00E+008

8.00E+007

6.00E+007

KDP+Erbium(Slow Evaporation) Eg=5eV

4.00E+007

2.00E+007

0.00E+000

-2.00E+007

Pure KDP

6.00E+007

Pure KDP KDP+Er (Slow Evaporation) KDP+Er (Seed Rotation) KDP+Er (SR Method)

35 30 25

4.00E+007

Eg=4.7eV

2.00E+007 0.00E+000

20 200

400

600

800

1000

Wavelength in nm

h

Fig. 9. (αhv)2 versus hv of the grown crystals.

Fig. 8. UV-Visible Spectrum of grown crystals.

SHG Studies. The Second harmonic generation efficiency was determined by Kurtz powder technique [14]. Laser beam coming from the source has very high energy. Its intensity is reduced by using glass plates and Neutral density (ND) filter which reduces the intensity and it allows only 1064 nm wavelength to incident on the sample taken in a microcapillary tube. Output from the sample is passed through the monochromator which is intensified by photomultiplier tube and finally the signal is observed and read on the Oscilloscope. A Q-switched Nd:YAG laser beam of wavelength 1064nm and 8ns pulse width with an input rate of 10Hz was used to test the NLO property of the sample. The second harmonic signal of 532nm green light was collected by a photomultiplier tube . The optical signal incident on the PMT was converted into voltage output at the cathode ray oscilloscope. The grown crystals were crushed into fine powder and tightly packed in a micro capillary tube. It was mounted in the path of Nd-YAG laser beam of energy 5mJ/pulse. The KDP crystal was used as a reference material. The transmitted beam voltage for pure KDP crystal was 4mV, for the Erbium doped KDP (Slow Evaporation method) crystal was 4.79mV, Erbium doped KDP (Seed Rotation method) crystal was 4.83mV, Erbium doped KDP (SRmethod) crystal was 5.43mV respectively. It is found that the SHG efficiency of the Erbium doped KDP (SR method) crystal is 1.35 times greater than KDP, Erbium doped KDP (Seed Rotation method) crystal is 1.2 times greater than KDP, and Erbium doped KDP (Slow Evaporation method) crystal is 1.19 times greater than KDP. The measured values are given in Table 5. Output intensity of SHG gives relative values of NLO efficiency of the material. The relative SHG efficiency of the grown crystals is higher than that of KDP sample which indicates the suitability of crystals for application in nonlinear optical devices and optoelectronic devices. The increased SHG efficiency is due to higher polarizability of the material than that of KDP.

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Table 5. SHG Signal and SHG efficiency of grown crystals. Details of the Sample

SHG Signal

SHG Efficiency w.r.t KDP

Pure KDP

4.00 mV

1.00

KDP doped Er (Slow Evaporation)

4.79 mV

1.19

KDP doped Er (Seed Rotation)

4.83 mV

1.20

KDP doped Er (SR method)

5.43 mV

1.35

Summary. A new additive rare earth Erbium was added to KDP and crystals were grown by slow evaporation method, microcontroller based seed rotation technique and SankaranarayananRamasamy (SR) method. Powder XRD and EDAX analysis confirm the fact that the Erbium has gone into the lattice sites of the KDP crystals. The presence of additional peaks in the XRD spectrum of doped KDP crystals shows the presence of additional phases due to doping. The UV-Vis-NIR transmission spectra show a wide transparency window without any absorption. KDP doped Erbium crystals generate optical second harmonic frequency of an Nd:YAG laser. The Kurtz powder technique indicates that the SHG efficiency Erbium doped KDP (SR method) crystal is 1.35 times greater than KDP, Erbium doped KDP (Seed Rotation method) crystal is 1.2 times greater than KDP, and Erbium doped KDP (Slow Evaporation method) crystal is 1.19 times greater than KDP, which indicates the suitability of crystals for application in nonlinear optical devices and optoelectronic devices. As the crystal has wide transparency in the UV and visible regions and with good SHG efficiency, implies that this crystal can be used as a potential material for optical applications. Acknowledgements. The scientific supports extended by Department of IPC for SHG studies, Department of physics for Xrd analysis, Department of materials Engineering for UV-Visible analysis, IISC, Bangalore are gratefully acknowledged. References [1] A. Yokotani., T. Sasaki., K.Yamanaka, C.Yamanaka, Appl. Phys. Lett. , 1986 , 48, 1030. [2] S.SenGupta, T.Kar, S.P.SenGupta, Mater.Chem.Phys., 1999,58,227. [3] D. Xu. D. Xue, J. Rare Earth, 2006, 24, 228. [4] L. N. Rashkovich, KDP Family of Single Crystals, Adam Hilger, New York, 1991. [5] J. W. Mullin, Crystallization, third ed., Butterworth Heinemann, London, 1993. [6] K. Srinivasan, K. Meera, P. Ramasamy, Cryst. Res. Technol., 2000, 35, 291. [7] M. Jayaprakasan, N.P. Rajesh, V. Kannan, R. Bairava Ganesh, G. Bhagavannarayana, P. Ramasamy, Mater. Lett., 2007, 61, 2419. [8] G. Li, X. Liping, G. Su, X. Zhuang, Z. Li, Y. He, J. Cryst. Growth, 2005, 274, 555. [9] P.V. Dhanaraj, N.P. Rajesh, C.K. Mahadevan, G. Bhagavannarayana, Physica B, 2009, 404, 25032508 [10] M. Nakatsuka, K. Fujioka, T. Kanabe, H. Fujita, J. Cryst. Growth, 1997, 171, 531. [11] G. W. Lu, and X. Sun, Cryst. Res. Technol., 2002, 37, 93. [12] B. W. Batterman and H. Cole, Rev. Mod. Phys., 1964, 36, 681 [13] K. Balasubramanian, P. Selvarajan and E. Kumar, Indian Journal of Science and Technology, 2010, Vol. 3 No.1.

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[14] R. Priya, G. Bhagavannarayana, S. Krishnan and S. Jerome Das, Archives of Applied Science Research, 2010, 2 (4), 111-118. [15] S.Suresh, A. Ramanand, P. Mani and K. Anand, Archives of Applied Science Research, 2010, 2 (4), 119-127. [16] S.K.Kurtz, T.T.Perry, J.Appl. Phys.., 1968, 39, 3798. Cite the paper V. Roopa, Dr. R. Ananda Kumari (2017) Comparative Study of Erbium Doped KDP Single Crystals Grown by Different Techniques. Mechanics, Materials Science & Engineering, Vol 9. doi mmse.84.25.878

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Crystal Growth, Optical, Dielectric, Mechanical and Second Harmonic Generation Characterization of 2,5-Dimethylanilinium Dihydrogen Phosphate Single Crystal14 A. Mani 1, 2, K. Rajesh 3, P. Praveen Kumar 1, a 1 –Department of Physics, Presidency College, Chennai, India 2 – Department of Physics, Sri Venkateswaraa College of Technology, Sriperumbudur, India 3 –Department of Physics, AMET University, Chennai, India a – ppkpresidency@gmail.com DOI 10.2412/ mmse.95.39.669 provided by Seo4U.link

Keywords: crystal growth, X-ray diffraction, optical properties, mechanical properties, NLO crystals.

ABSTRACT. Single crystals of 2,5-dimethylanilinium dihydrogen phosphate (2,5-DADP) were grown by slow evaporation solution growth technique in room temperature. The crystalline nature of the grown crystal was confirmed from the single crystal X-ray data. The grown crystal 2,5-DADP was found to crystallize in orthorhombic system with non-centrosymmetric space group P212121. Optical transparency of the grown crystal was studied by UV–Vis-NIR spectroscopy. The dielectric loss and dielectric constant measurement as a frequency and temperature were measured on 2,5-DADP single crystal. Microhardness measurements revealed that 2,5-DADP belongs to a soft material category .The second harmonic generation of the crystal was confirmed and the efficiency was measured using Kurtz Perry powder method.

Introduction. Nonlinear optical (NLO) materials are a new frontier of science and development for optoelectronics due to their potential applications such as optical computing, 3D optical data storage, color displays, optical power limiting, optical communications, laser fusion, etc. [1]. Inorganic nonlinear optical single crystals have usually high melting point, high mechanical strength, and high degree of chemical inertness, but very poor second and third harmonic generation efficiencies. The nonlinearity of inorganic materials is low compared to organic NLO crystals [2]. In contrast, organic crystals exhibit large NLO coefficients and synthetic flexibility but they have very poor transparency, short optical band gap, laser damage threshold, thermaland mechanical properties [3]. The search for new NLO materials with improved stability (thermal, mechanical and chemical) and a wide transparency window has resulted in the development of the new class of materials called semiorganics. Materials with combined described charteristicnamed semi-organic, can be grown easily by solution growth technique [4]. A number of phosphate acid complexes have been studied as promising materials for second harmonic generation [5-7]. 2,5-Dimethylanilinium dihydrogen phosphate (2,5-DADP) belongs to this large semi-organic NLO family. The crystal structure of this compound was elucidated by K.Kaabi et al[8]. S. Guidara et al [9] have reported the DFT calculation and structural parameter calculations of the title compound. Since few properties of 2,5-DADP crystals have been reported earlier, in the present work a systematic study has been carry outvarious properties of the material. In the present investigation, attempts were made to grow good quality single crystals of 2,5-DADP by the slow evaporation solution growth method. The crystals were characterized using single crystal XRD, UV-

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Vis-NIR, dielectric, mechanical studies were carried out. The second harmonic generation property of the crystal was tested. Crystal growth. Single crystals of 2,5-dimethylanilinium dihydrogen phosphate (2,5-DADP) were grown by the slow evaporation solution growth technique. The title compound was prepared by slow addition of phosphoric acid to an ethanolic solution of 2,5-dimethylaniline in a 1:1 molar ratio. The chemical reaction is 2,5-(CH3)2C6H3NH2 + H3PO4

[2,5-(CH3)2C6H3NH3]H2PO4

The solution was stirred continuously using a magnetic stirrer. A crystalline precipitate was formed. After adding distilled water, the resulting solution was mixed well using a magnetic stirrer to ensure homogeneous concentration in the entire volume of the solution. The prepared solution was filtered and kept undisturbed at room temperature. The slow evaporation of solvent during 20 days leads to the formation of colorless and transparent prismatic crystals of 2,5-DADP. Repeated recrystallization yielded to good quality crystal as shown in Fig. 1b. Single crystal X-ray diffraction. Single crystal X-ray diffraction (XRD) analysis on 2,5-DADP crystal was carried out using EnrafNonius CAD4-MV31diffractometer with MoKα (λ = 0.71073 Ǻ) radiation. The X-ray diffraction study confirmed that the crystal belongs to orthorhombic system with the non-centrosymmetric space group P212121. The lattice parameters of 2,5-DADP crystal were measured as a = 5.826 Ǻ, b = 21.063 Ǻ, c = 8.467 Ǻ, α = β = γ = 90°, and the cell volume V = 1039.011 A3. These values agree well with the reported value [8]. UV–vis–NIR spectral study. The optical transmittance study is used to identify the optical transmission range and cut-off wavelength of crystals because a nonlinear optical crystal can be of practical use if it has wide transparency window. The transmission spectra were recorded using Perkin Elmer lambda 35 UV–vis–NIR spectrometer in the spectral region 190–110 nm with spectral resolution 2 nm as shown in Fig.1a. The optical cut-off wavelength of the 2,5-DADP crystal was found to be 325 nm, and the crystals had good optical transmittance between 325 and 1100 nm (VisNIR region).

Fig. 1. (a) Optical transmittance spectrum (b) Photograph of as-grown 2,5-DADP single crystal (c) a plot of (αhυ)2 against photon energy. The optical absorption coefficient (α) was determined usingthe relation, MMSE Journal. Open Access www.mmse.xyz

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đ?&#x203A;ź=

1 đ?&#x2018;&#x2021;

2.303 log( ) đ?&#x2018;Ą

(1)

where T is the transmittance and t is the thickness of the crystal. As a direct band gap (Eg) has been determined from the transmission spectra, the optical absorption coefficient of the crystal (Îą) near the absorption edge is given by the following relation: đ?&#x203A;źâ&#x201E;&#x17D;đ?&#x153;? = đ??´ (â&#x201E;&#x17D;đ?&#x153;? â&#x2C6;&#x2019; đ??¸đ?&#x2018;&#x201D; )1/2

(2)

where A is a optical transition dependent constant, Eg is the optical band gap of the crystal, h is the Planckâ&#x20AC;&#x2122;s constant, and Ď&#x2026; is the frequency of incident photons. The band gap of the 2,5-DADP crystal was estimated by plotting (ÎąhĎ&#x2026;)2 against the photon energy (hĎ&#x2026;) (Tauc's plot) as shown in Fig. 1c. The band-gap energy (Eg) of the grown crystal was estimated by exploring a straight line in the linear region near the onset of the absorption edge to the energy axis (ÎąhĎ&#x2026;)2= 0. From Fig. 1c, the estimated band-gap energy was found to be 3.79 eV. The wide band gap of the 2,5-DADP crystal confirms the large transmittance window in the visible region. Dielectric studies. Dielectric behavior was studied using a HIOKI 3532-50 LCR HITESTER. The precisely cut and polished crystal was mounted in the sample holder. Measurements were made in the frequency range of 100 Hzâ&#x20AC;&#x201C;5 MHz at three different temperatures.

Fig. 2. (a) Variation of dielectric constant with log frequency (b).Variation of dielectric loss with log frequency at different temperatures. Dielectric properties of 2,5-DADP (dielectric constant and dielectric loss ) were recorded with respect to frequency and temperature (Figs. 2a and 2b).It is noticed that both dielectric constant and dielectric loss show similar behavior with respect to frequency. Values of dielectric constant and dielectric loss are high at low frequency, and decreases with increase in frequency. Further increase in frequency does not have any impact on the dielectric constant and dielectric loss and the values remain constant. Though, all types of polarization are active at low frequency region, high value of dielectric constant is mainly attributed to the space charge polarization. The large value of dielectric constant at low frequency is due to the presence of space charge polarization. The low values of both dielectric constant and dielectric loss at high frequencies confirm that the optical quality of 2,5-DADP is quite MMSE Journal. Open Access www.mmse.xyz

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good and thus suitable for NLO application. The unique behavior of 2,5-DADP mentioned earlier also points towards its suitability for applications like insulation for wires and cables, ferroelectric, photonic and electro-optic, sensor devices and capacitors . Vickers Microhardness Test. Analysis of mechanical property of the grown crystal is also important for the fabrication of electronic and optical devices. Microharness studies have been carried out on a selected well transparent single crystal using microharness tester, fitted with a Vickers diamond pyramidal indenter. The indentations were made on the 2,5-DADP crystals with applied load ranging from 5 g to 50 g. The time of indentation was kept constant for 5 s. The values of Vickers microhardness at different loads were calculated using the relation, đ??ťđ?&#x2018;&#x2030; =

1.8544Ă&#x2014;đ?&#x2018;&#x192; đ?&#x2018;&#x2018;2

(đ??žđ?&#x2018;&#x201D;â &#x201E;đ?&#x2018;&#x161;đ?&#x2018;&#x161;2 )

(3)

where P is the applied load and d is the mean diagonal length of the indenter impression. Fig. 3a shows the variation of hardness with the applied load. It is observed that the hardness of 2,5DADP increases by increasing load up to 50 g which indicates the reverse indentation size effect. The cracks start to occur after the load 50 g.

Fig. 3. (a) Plot of Hardness number vs. Load P. (b) Plot of log d vs log P of 2,5-DADP crystal. This may be due to the release of internal stress generated locally by indentation. The work hardening coefficient (n) of the material was calculated using the relation P = kdn, where k is the arbitrary constant of a given material, and n is the work hardening coefficient. Onitsch [10] and Hanneman have pointed out that n lies between 1 and 1.6 for moderately hard materials and more than 1.6 for soft category materials, where n is Meyerâ&#x20AC;&#x2122;s index. According to Meyerâ&#x20AC;&#x2122;s law, the relation between load and the size of indentation can be correlated. The graph plotted between log P vs log d (Fig. 3b) gives the work hardening coefficient (n), and n is found to be 2.87 followed by the least-squares fitting method. NLO studies. The NLO property of the crystal was confirmed by Kurtz powder technique. The determination of SHG intensity of the crystals using powder technique was developed by Kurtz and Perry [11]. The crystals are ground to powder and packed between two transparent glass slides. The first harmonic output of 1064 nm from a Nd:YAG laser was made to fall normally on the prepared sample with a pulse width of 8 ns. The power of incident laser beam was measured as4.3 mJ/pulse. The output radiation from the crystal was allowed to fall on a photomultiplier tube which converts the light signal into electrical signal. The second harmonic signal generated in the crystal was MMSE Journal. Open Access www.mmse.xyz

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confirmed from the emission of green radiation by the sample. It is found that the SHG efficiency of the crystal is 1.4 times higher than that of KDP. Summary. Optical defect free crystal of 2,5-Dimethylanilinium dihydrogen phosphate (2,5-DADP) was grown by slow evaporation solution growth method. The crystal structure was confirmed by single crystal XRD analysis. The optical studies reveal that the grown crystals have a cut-off wavelength of 325 nm and the band gap is found to be 3.79 eV. Frequency and temperature dependent dielectric studies showed that 2,5-DADP crystal exhibit normal dielectric behavior and established the aptness for NLO applications. Vickersmicrohardness study indicates the mechanical stability of the crystal.SHG efficiency of the grown crystal is 1.4 times that of KDP. Reference [1] Chemla DS, Zyss J (eds), Nonlinear optical properties of organic molecule and crystals, vol 1 and 2. Academic press, New York, 1987, ISBN: 0121706117, 9780121706111 [2] Ledoux S, Zyss J, Nonlinear organic molecules and materials for optoelectronic devices. J. Nonlinear Optic. Phys. Mat.03:287–316,1994.DOI: 10.1142/S0218199194000183 [3] Marcy HO, Warren LF, Webb MS, Ebbers CA, Velsko SP, Kennedy GC, Catella GC, Secondharmonic generation in zinc tris(thiourea) sulfate,Appl Opt. 31:5051–5060,1992DOI: 10.1364/AO.31.005051. [4] K. Rajesh, V. Thayanithi, A. Mani, M. Amudha, P. Praveen Kumar, Solubility, Thermal, Photoconductivity and Laser Damage threshold studies on L-Serine Acetate (LSA) Single crystal, AIP Conf Proc.1665, 100021, 2015, DOI: 10.1063/1.4918049 [5] V. Rajendran, D. Shyamala, M. Loganayaki, P. Ramasamy, Growth and characterization of a new non-linear optical L-histidiniumdihydrogen phosphate single crystal. Materials Letters 61:3477-3479, 2007,DOI:10.1016/j.matlet.2006.11.112 [6] A.P. Jeyakumari, S. Manivannan, S. Dhanuskodi, Spectral and optical studies of 2-amino-5nitropyridinium dihydrogen phosphate: A semiorganicnonlinear optical material.Spectrochim. Acta, Part A, 67A, 83-86, 2007. DOI:10.1016/j.saa.2006.06.027 [7] K. Rajesh, A. Mani , V. Thayanithi, and P. Praveen kumar,Optical, Thermal, and Mechanical Properties of L-Serine Phosphate, a Semi organic Enhanced NLO Single Crystal. Int. J. Optics, 2016, Article ID 9070714. DOI: 10.1155/2016/9070714 [8] K. Kaabi, C. Ben Nasr, M. Rzaigui, Synthesis and characterization of a new monophosphate [2,5(CH3)2C6H3NH3]H2PO4,J. Phys. Chem. Solids.65:1759-1764, 2004.DOI:10.1016/j.jpcs.2004.04.003 [9] S. Guidara, H. Feki, Y. Abid, Molecular structure, NLO, MEP, NBO analysis and spectroscopic characterization of 2,5-Dimethylanilinium dihydrogen phosphate with experimental (FT-IR and FTRaman) techniques and DFT calculations.Spectrochim. Acta, Part A, 133A, 856–866, 2014. DOI: 10.1016/j.saa.2014.06.021 [10] E. M. Onitsch, The present status of testing the hardness of materials, Mikroskopie. 1947, 2, 131. [11] S.K. Kurtz, T.T. Perry, A Powder Technique for the Evaluation of NonlinearOptical Materials.J. Appl. Phys. 36: 3798, 1968.DOI: 10.1063/1.1656857 Cite the paper A. Mani, K. Rajesh, P. Praveen Kumar (2017). Crystal Growth, Optical, Dielectric, Mechanical and Second Harmonic Generation Characterization of 2,5-Dimethylanilinium Dihydrogen Phosphate Single Crystal.Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.95.39.669

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Comparative Study of Properties of L-Histidine and L-Histidine Nickel Nitrate Hexahydrate Crystals Grown by Slow Evaporation15 R. Vinayagamoorthy1, a, A. Albert Irudayaraj1, A. Dhayal Raj1, S. Karthick1, G. Jayakumar1 1 – PG and Research Department of Physics, Sacred Heart College, Tirupattur, Vellore, India a – vinayaga76@gmail.com DOI 10.2412/mmse.83.74.689 provided by Seo4U.link

Keywords: Semi organic, Amino acid, Phase transition, SHG efficiency.

ABSTRACT. L-Histidine (LH) is an amino acid. It is an organic material. L-Histidine Nickel Nitrate Hexahydrate (LHNNH) is a semi organic material. It is a complex of bivalent nickel ion with L-Histidine amino acid. Complexes of bivalent metal ions with amino acids are generally good NLO materials. Crystals of L-Histidine and L-Histidine Nickel Nitrate Hexahydrate (LHNNH) have been successfully grown by slow evaporation method using water as solvent. The crystal structure and lattice parameters of LH and LHNNH are determined by Single crystal X-ray diffraction analysis. The functional groups in LH and LHNNH are confirmed by FTIR analysis. With the help of UV-Vis spectroscopy the optical band gap and optical transparency are studied. The chemical composition of LH and LHNNH are studied by CHN and EDAX analysis. Thermally stability and thermal phase transitions of LH and LHNNH are analyzed by TGA/DTA. The Second Harmonic Generation (SHG) efficiency of LH and LHNNH have been experimentally estimated.

Introduction: L-Histidine is an optically active α-amino acid and is a tridentate ligand that has an imidazole ring, amino and carboxylate groups. Amino acids are the potential candidates for optical second harmonic generation because they contain chiral carbon atom and crystallize in non-centro symmetric space groups and it is an essential criterion for nonlinear application [1]. Amino acids are interesting materials for NLO applications. Complexes of amino acids with inorganic salts are promising materials for optical Second Harmonic Generation. In recent years semi organic crystals have emerged as extremely promising building blocks for NLO materials. They share the properties of both organic and inorganic materials. Amino acids are interesting materials for NLO applications, as they exhibit molecular chirality, absence of strongly conjugated bonds and zwitterionic nature of the molecule [2]. Hence L-Glutamine, L-Serine , L-Histidine, L-Alanine and L-Valine have been subjected for the formation of salts with different inorganic acids. As a result very good semiorganic nonlinear optical materials such as L-Glutamine sodium nitrate [3], L-Serine sodium nitrate [4], L-Alanine cadmium chloride [5], L-Histidine cadmium chloride monohydrate [6], L-Histidine barium chloride dihydrate [7] and L-Valine cadmium chloride [8] are some of the good examples which proved very suitable materials for NLO applications. In the present investigation an attempt has been made to grow L-Histidine and L-Histidine Nickel Nitrate Hexahydrate by slow evaporation method at room temperature. The grown crystals have been subjected to Single crystal, FTIR, UV-Visible, CHN, EDAX, TG/DTA and NLO studies. Experimental procedure Preparation of LH and LHNNH: The saturated solution of LH was prepared from the commercially available LH and the prepared solution was filtered using wattmann filter paper. The solution was © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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transferred into a petri dish and covered with the polythene paper. Holes were made on the cover and the solution was allowed for the evaporation. After a period of few months, L-Histidine crystals were collected. L-Histidine Nickel Nitrate Hexahydrate (LHNNH) was synthesized from L-Histidine and Nickel Nitrate Hexahydrate according to the following reaction.

2[C6H9N3O2] + Ni (No3)2.

6H2O [C6H9N3O2]2

Ni (No ) .6H O

2 2 L-Histidine and Nickel 3Nitrate Hexahydrate were taken in the molar ratio (2:1). The calculated amount of L-Histidine was first dissolved in 100ml de-ionized water. Followed by Nickel Nitrate Hexahydrate was added to the solution slowly by continuous stirring to get a homogeneous mixture. Then the solution was left undisturbed. After few months, L-Histidine Nickel Nitrate Hexahydrate raw material was collected. The Crystals of LH and LHNNH were recrystallized thrice to improve the purity of the crystal. Good quality crystals of LH and LHNNH were obtained. Photograph of the grown LH and LHNNH crystals are shown in Figure 1.

(b)LHNNH

(a)LH

Fig. 1. As grown (a) LH (b) LHNNH. Single crystal X-ray diffraction analysis: The single crystal X-ray analysis of LH and LHNNH crystal was carried out using an X-ray diffractometer (ENRAF NONIUS CAD4-MV31 BRUKER KAPPA APEX II). It was observed that both the crystals possess orthorhombic system and space group P212121. The lattice parameter values of LH and LHNNH are a=5.14(Å), b=7. 32(Å), c=18.76(Å), V=705.84(Å3)[9] and a=15.74(Å), b=13.17(Å), c=7.31(Å), V=1515.33(Å3) respectively. Fourier Transform Infrared (FTIR) Spectral analysis: To analyze the presence of functional groups in LH and LHNNH crystals, the infrared was recorded in the range from 400 cm-1 to 4000 cm1 with the help of PERKIN ELMER FTIR spectrometer using KBr pellet. The recorded FTIR spectrum of LH and LHNNH were shown in Figure 2. In the higher wave number region the CH 2 asymmetric stretching peak at 2714 cm-1. The peak at 1635 cm-1 is due to C=O stretching. The peak at 1563 cm-1 is due to C=C stretching. The peak at 1468 cm-1 is due to NH2 bending. The peak at 1156 cm-1 is due to C-H in plane bending. The peak at 1073 cm-1 is due to C-O stretching of carboxyl group. The peak at 904 cm-1 is due to ring symmetric stretching. The peak at 845 cm-1 is due to C-N out of plane bending. The peak at 779 cm-1 is due to C-N deformation. The peak at 701 cm-1 is due to out of plane bending of NH2.

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Fig. 2. FTIR Spectrum of (a) LH (b) LHNNH. The peak at 632 cm-1 is due to C-H deformation. The peak at 527 cm-1 is due to torsion oscillation of NH3+. On the other hand, in the case of L-Histidine crystal sample almost all the important vibration modes corresponding to respective functional groups have been observed [10]. The assignments confirm the presence of various functional groups of LH and LHNNH. UV-Visible spectral analysis: UV-Vis transmission spectrum of LHNNH crystal was recorded using Perkin Elmer make Lambda 35 UV-Visible Spectrometer in the range 200nm to 800nm and the observed spectrum of LHNNH crystal is shown in Figure 3. The LH and LHNNH crystal are transparent in the entire UVâ&#x20AC;&#x201C;Visible region. It has a transparency of about 85% with a lower cut-off wavelength at 228nm and 254nm. The wide range transmission is an important requirement for a crystal exhibiting NLO behavior. The optical band gap as calculated from UV-Vis analysis was found to be 5.44 eV and 4.89 eV respectively.

Fig. 3. UV-Visible Spectrum of (a) LH (b) LHNNH. CHN Analysis: The percentage composition of the C, H, and N elements in the synthesized LH and LHNNH was examined by CHN analysis using Elemental vario micro CHN Analyzer. The MMSE Journal. Open Access www.mmse.xyz

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percentage composition LH of carbon, hydrogen and nitrogen are C=46.44 % (46.75), H=5.84% (6.05) and N=27.08% (27.38). The percentage composition LHNNH of carbon, hydrogen and nitrogen are C=21.32 % (21.79), H=2.68% (3.91) and N=20.73% (19.23). EDAX Analysis

Fig. 4. EDAX Spectrum of LHNNH. Energy dispersive X-ray analysis (EDAX) was an analytical technique. It was used to obtain useful information regarding the chemical composition of the grown crystal. The grown crystal was subjected to EDAX analysis using the instrument FEI QUANTA FEG 250 scanning electron microscope. A fine beam of X-rays was made to fall into the LHNNH sample. The number and energy of the X-rays emitted by the sample was measured of the X-rays emitted from the sample was attributed to the energy difference between the two shells and of the atomic structure of the compound, the elemental composition of the specimen can be measured. The EDAX spectrum of LHNNH is shown in Figure 4.

Fig. 5. TGA and DTA curves of (a) LH (b) LHNNH. Thermal analysis: The thermo gravimetric analysis (TGA) and differential thermal Analyses (DTA) for LH and LHNNH have been carried out in the temperature range of 20 - 400Â°C using a CNST MMSE Journal. Open Access www.mmse.xyz

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thermal analyzer. Alumina pan was used for heating and the analysis was performed in an atmosphere of nitrogen at a heating rate of 20°C/min. The results were presented in Figure.5. In TGA, it was found that LH and LHNNH crystal were stable up to 268°C and 78°C. The melting point of LH is 288°C [10]. The DTA, LHNNH indicates the exothermic covering the temperature range 152°C to 210°C. NLO studies. The nonlinear optical conversion efficiency test was carried out for the grown crystals using Kurtz-Perry Powder technique. KDP was used as reference for the present measurement. The emission of green light confirmed generation of second harmonic radiation. The second harmonic generation efficiency of LH and LHNNH are found to be 0.72 and 0.39 times to that of KDP. Summary. Single crystals of L-histidine and L-histidine nickel nitrate hexahydrate have been grown by slow evaporation method using water as solvent. The structure of LH and LHNNH are Orthorhombic with the space group P212121. The functional groups in LH and LHNNH are confirmed by FTIR analysis. The LH and LHNNH are transparent in the entire UV-Visible region. The transparency of the crystal is above 85%. The UV lower cut off wavelength of LH and LHNNH crystals occurs at 228nm and 254nm. The optical band gap is found to be 5.44 eV and 4.89 eV. The chemical composition of LH and LHNNH are studied by CHN and EDAX analysis. The LH and LHNNH are thermally stable up to 268C and 78C. The melting point of LH is 288C. The second harmonic generation efficiency of LH and LHNNH were found to be 0.72 and 0.39 times to that of KDP. References [1] P. Praveen Kumar, V. Manivannan, S.Tamilselvan, S. Senthil, Victor Antony Raj, P. Sagayaraj, J. Madhavan, Growth and characterization of a pure and doped nonlinear optical L-Histidine acetate single crystal, Optics Communications 2008, 281, 2989-2995. 10.1016/j.optcom.2008.01.058. [2] C. Alosious Gonsago, Helen Merina Albert, J. Karthikeyan, P. Joseph Arul Pragasam, Crystal structure, optical and thermalstudies of a new organic nonlinear optical material: L-histidinium maleate 1.5-hydrate, Materials Research Bulletin, 2012, 47, 1648-1652. 10.1016/j.materresbull.2012.03.061. [3] Redrothu Hanumanthrao, S. Kalainathan, Studies on structural, thermal and optical properties of novel NLO crystal bis L-glutamine sodium nitrate, Materials Letters, 2012, 74, 74-77. 10.1016/j.matlet.2012.01.051. [4] P. Koteeswari, S. Suresh, P. Mani, Synthesis, Theoretical, Mechanical and Dielectric Property of L-Serine sodium nitrate NLO single crystal, American Journal of Condensed Matter Physics, 2012, 2(5), 116-119. 10.5923/j.ajccmp.20120205.02. [5] S. Dhanuskodi, K. Vasantha, P. A. Angeli Mary, Structural and thermal characterization of a semiorganic NLO material: L-Alanine cadmium chloride, Spectrochimica Acta Part A, 2007. 10.1016/j.saa.2005.06.052. [6] J. Chandrasekaran, P. Ilayabarathi, P. Maadeswaran, P. Mohamed Kutty, S. Pari, Growth and characterization of L-histidine cadmium chloride monohydrate a semiorganic nonlinear optical materials, Optics Communications, 2012, 285, 2096-2100. 10.1016/j.optcom.2011.12.063. [7] T. R. Beena T. Chithambarathanu, S.L. Rayar, Growth and characterization of a semiorganic NLO material: L-histidine barium chloride dihydrate, Green Chemistry & Technoloty Letters, 2016, V-2, No.1, 26-30. 10.18510/getl.2015.215. [8] P. Maadeswaran, J. Chandrasekaran, Synthesis, growth and characterization of L-valine cadmium chloride monohydrate- A novel semiorganic nonlinear optical crystal, Optik, 2011, 122, 11281131.10.1016/j.ijleo.2010.07.006. [9] P. Anandan, M. Arivanandan, Y. Hayakawa, D. Rajan Babu, R. Jayavel, G. Ravi, G. Bhagavannarayana, Investigations on the growth aspects and characterization of semiorganic MMSE Journal. Open Access www.mmse.xyz

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nonlinear optical single crystals of L-histidine and its hydrochloride derivative, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014, 121, 508-513. 10.1016/j.saa.2013.11.021. [10] Yun Zhang, Hua Li, Bin Xi, Yunxia Che, Jimin Zheng, Growth and characterization of Lhistidine nitrate single crystal, a promising semiorganic NLO material, Materials Chemistry and Physics, 2008, 108, 192-195. 10.1016/j.matchemphy.2007.09.006. Cite the paper R. Vinayagamoorthy, A. Albert Irudayaraj, A. Dhayal Raj, S. Karthick, G. Jayakumar (2017). Comparative Study of Properties of L-Histidine and L-Histidine Nickel Nitrate Hexahydrate Crystals Grown by Slow Evaporation. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.83.74.689

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Growth and Characterization of Unidirectional Grown Imidazolium L-Tartrate (IMLT) Single Crystal by SR Method16 V. Thayanithi1, P. Praveen Kumar1,a 1 – Department of Physics, Presidency College, Chennai, India a – ppkpresidency@gmail.com DOI 10.2412/mmse.13.44.508 provided by Seo4U.link

Keywords: Slow evaporation, SR method, Single XRD, Photoluminescence, Nonlinear optics.

ABSTRACT. The second order non-linear optical material Imidazolium L-Tartrate (IMLT) seed crystal was successfully grown by slow evaporation method. <0 0 1> plane unidirectional crystal was successfully grown by Sankaranarayanan and Ramasamy (SR) method. The growth of conventional and SR grown crystals were optimized. Cell parameter, space group and morphology of the grown conventional method crystal were found by single XRD. Transparency of the grown IMLT crystals by conventional and SR method were compared by UV-Vis-NIR spectroscopy. Emission spectrum of the grown IMLT crystals were analysed by Photoluminescence. Dielectric constant and Dielectric loss of the grown crystals were analysed. Mechanical strength of the grown IMLT crystals was determined by Vickers hardness test.

Introduction. Chiral organic compounds with high order nonlinear susceptibility (χ(n)) are fast response than inorganic compounds in optical application such as optical communication, optical data storage, terahetz generation. In recent years, many researchers give more attention on the organic compounds because organic compounds are crystallizing with hydrogen bonds, large dipole moment, weak van dar Waals force, accentric crystal structure [1-3]. The aromatic heterocyclic organic compound of imidazole react with organic and inorganic acid and its forms hydrogen bond and delocalized π-electron system, which enhance the molecular hyper-polarizability is potentially effective strategy for crystallizing nonlinear optical materials [4-6]. It is difficult to grow specific oriented bulk size crystal without defects from solution by slow evaporation method for device application. In this point of view Sankaranaryanan and Ramasamy (SR) method has been applied to grow unidirectional crystal from solution [7, 8]. In this present investigation, Imidazolium tartrate was successfully grown unidirectional by SR method. Single XRD conformed crystalline nature. Grown crystal was subjected to UV-Vis NIR spectroscopy, photoluminescence, Dielectric and Mechanical strength. Experimental procedure.Title of the compound imidazolium tartrate was synthesized by dissolving of Imidazole and L-Tartaric acid equimolar ratio in de-ionized water and the reaction scheme of crystal is shown in Fig 1. The mixed solution was stirred well upto 6 hours. After saturation was attained, the solution was filtered into beaker and covered polythene paper with few holes and retained at dust free place. Crystals were obtained from mother solution within a week by slow evaporation method. Repeated recrystallization was take place to improve crystal perfection. Good transparent crystal was selected and dipped into beaker with mother solution. After 20 days of time period, 15 × 10 × 3 mm3 dimension crystal was obtained from solution. The photograph of the grown crystal by conventional method is shown in Fig 2a. Growth setup of SR method [7] was constructed. C-axis < 0 0 1> plane was selected, based on the morphology of the conventional grown crystal. The selected crystal was placed in bottom of the © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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ampoule and <0 0 1> plane was oriented towards the saturated solution. Evaporation of the solvent take place at top portion by ring heater, seed crystal was initiated to crystallize. Temperature of top portion was maintained at 315 K. After 30 days of period, IMLT crystal with 28 mm of length and 15 mm of diameter was obtained. The photograph of the grown by SR method crystal is shown in Fig. 2b.

Fig. 1. Reaction scheme of the grown IMLT crystal. Result and Discussion The grown IMLT crystal was subjected to single crystal XRD by using ENRAF NONIUS CAD4 diffractormeter. The grown IMLT crystal resides to monoclinic crystal system with noncentrosymmetric space group P21. Cell parameters values of grown IMLT crystal are a = 7.55 Ǻ, b = 6.93 Ǻ, c = 8.97 Ǻ, β = 102.05 and volume V = 469.32 Ǻ3, which are in good agreement with reported values [9]. Morphology of the grown crystal was identified by X-ray goniometry and it was drawn by using Winxmorph software. Morphology of the grown crystal shows that it is in bar shape. <0 0 1> plane is dominant and major growth direction along with c-axis of the grown IMLT crystal. Morphology of the grown IMLT crystal is shown in Fig. 2c. Single X-ray Diffraction.

Fig. 2. The photograph of grown crystal (a) conventional method (b) SR method (c) Morphology of the grown crystal. UV-Vis NIR analysis.Linear optical properties of the grown IMLT crystals transmittance were examined by UV-Vis NIR spectrum, recorded using Shimadzu spectrometer in range 200 nm to 800 nm. The lower cut of wavelength of grown IMLT crystal absorbed at 235 nm. The transmittance percentage of the grown IMLT of SR method and conventional crystals has 49 % and 33 % respectively in visible region. The transmittance percentage of the grown SR method crystal is

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increased 16 % than conventional method. The recorded transmittance spectra of the grown IMLT crystals were shown in Fig 3. Photoluminescence spectroscopy.Photoluminescence emission spectrum was recorded for the conventional and SR grown crystals using Bruker S4 pioneer in the range 300 – 800 nm. The emission wavelength of the grown IMLT crystals observed at 535 nm and it corresponds to emission region. The emission spectra of the grown IMLT crystals are shown in Fig 4.

Fig. 3. Transmittance spectra of the grown IMLT crystals.

Fig. 4. Emission spectra of the grown IMLT crystals.

Dielectric studies. Dielectric constant (εr) and Dielectric loss (tan δ) of the grown IMLT crystals were studied by using Agilent 4284-A LCR meter. The cut polished of the grown IMLT crystals of SR method and conventional method were mounted in sample holder and the dielectric measurements were carried out in the frequency range 100 Hz – 5 MHz at room temperature. The dielectric constant of the grown IMLT crystals by SR method and conventional method is decreases with increasing frequency [10] and it is shown in Fig. 5, a. The dielectric constant of the grown IMLT crystal by SR method has higher value compared than conventional crystal. The dielectric constant of the grown crystals is due to the contribution of dipolar, ionic, electronic and space charge polarization and it depend, on the frequency. The dielectric loss of the grown IMLT of SR method and conventional crystals are shown in Fig. 5, b. The dielectric loss of the grown IMLT of SR method crystal is lesser than conventional method, due to lesser defects in crystalline nature [11].

Fig. 5. (a) Dielectric constant versus log (f), (b) Dielectric loss versus log (f).

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Microhardness studies.Vicker’s microhardness test determes the mechanical strength of the grown IMLT crystal by SR method and conventional method and it is taken by Leitz-wetzler hardness tester with diamond indenter. The load P indentation is range from 10 g to 100 g. The microhardness value was calculated using this formula Hv = (1.8544) P/ d2 Kg/mm2 where Hv (Kg/mm2) is Vickers hardness number; P (g) is applied load; d (μm) is average diagonal length of the indentation mark. The hardness value of the grown IMLT of SR method and conventional crystal is decreases with increasing load. The hardness value of the grown IMLT crystal by SR method is higher than the conventional crystal and it is shown in Fig 6. The work hardening coefficient n (Meyer’s index) was calculated [11]. The calculated hardness coefficient (n) values of the grown IMLT of SR method crystal and conventional crystal are 1.85 and 1.96 respectively. From this hardness coefficient values of IMLT crystals are in soft category and SR grown crystal have higher hardness compare than conventional crystal.

Fig. 6. Vicker’s hardness analysis for the grown IMLT crystal. Summary. Optically good quality crystal of noncentrosymmetric Imidazolium Tartrate crystal has been successfully grown using conventional and SR method. The grown crystal belongs to the monoclinic system with noncentrosymmetric space group P21. The optical transmittance of the grown IMLT crystal by SR method is increased 16 % than conventional method and lower cut of wavelength found to be 235 nm. The emission wavelength of the grown IMLT crystals observed at 535 nm and they are in green emission region. The grown IMLT crystal by SR method has high dielectric constant with low dielectric loss compared than the conventional method crystal. The hardness value (H v) of the grown IMLT crystal by SR method has high compared than conventional crystal. It is conclude that the grown IMLT crystal by SR method is good promising NLO material compared than conventional method. Acknowledgements The authors acknowledge the SAIF IIT, Madras for characterization studies.

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References [1] D.S. Chemla, J. Zyss (Eds) Nonlinear optical properties of organic molecules and crystals, vol I, Academic press, New York, 1987. [2] Nalwa, H. S.; Watanabe, T.; Miyata, S. In Nonlinear Optics of Organic Molecules and Polymers; Nalwa, H. S., Miyata, S., Eds.; CRC Press: Boca Raton, FL, 1997; Chapter 4. [3] K. Rajesh, P. Praveen Kumar, J. Mater. 2014 (2014) 5. [4] H.S. Nalwa, S. Miyata, Nonlinear Optics of Organic Molecules and Polymers, CRC Press, Boca Raton, FL, USA, 1997. [5] S. Manivannan and S. 10.1016/j.jcrysgro.2003.10.029

Dhanuskodi,

Cryst.

Growth,

2004,

262,

473,DOI:

[6] M. Amudha, R. Rajkumar, V. Thayanithi and P. Praveen Kumar, Adv. In Opt. Tech.(2015) 9. [7] Sankaranarayanan K, Ramasamy P. J Crystal Growth 280 (2005) 467–73. [8] Balamurugan N, Ramasamy 10.1016/j.matlet.2008.04.078

Cryst

Growth

Des

(2006)

1642–4,DOI:

[9] C. Ji, T. Chen, Z. Sun, Y. Ge, W. Lin, J. Luo, Q. Shi and M. Hongb, Cryst. Comm. Eng. 15 (2013) 2157. [10] R. Uthrakumar, C. Vesta, C. Justin Raj, S. Krishnan, S. Jerome Das, Current Applied Physics 10 (2010) 548–552. [11] A. Zamara, K. Rajesh, A. Thirugnanam, P. Praveen Kumar, Optick (2014). [12] M. Senthil Pandian, P. Ramasamy, J. Cryst. Grow. 312 (2010) 413–419. Cite the paper V. Thayanithi, P. Praveen Kumar (2017). Growth and Characterization of Unidirectional Grown Imidazolium L-Tartrate (IMLT) Single Crystal by SR Method. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.13.44.508

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Growth, Nonlinear, Dielectric Studies on Urea Phosphoric Acid (UP) Single Crystals17 N. Hema1, R. Usha1, D. Shalini1, V. Revathi Ambika1, D. Jayalakshmi2, a 1 – Research Scholar, Dept Of Physics, Queen Mary’s College, Chennai, India 2 – Asst. Prof, PG & Research, Dept Of Physics, Queen Mary’s College, Chennai, India a –hemavprabu@gmail.com DOI 10.2412/mmse.77.39.252 provided by Seo4U.link

Keywords: X-ray diffraction, solubility, growth from solutions, organic compounds, nonlinear optical material, second harmonic generation.

ABSTRACT. An organic nonlinear optical Urea phosphoric acid (UP) single crystal has been grown by slow evaporation solution growth technique. The cell parameters of UP single crystal were confirmed by single X-ray diffraction analysis. The presence of functional groups was identified by FT-IR spectral analysis. The UV-Vis spectral studies showed that the UP single crystal has wide transmission window in the entire visible region. The dielectric property of UP crystal revealed the normal dielectric behaviour. Mechanical strength of UP crystal was studied.The second order nonlinear coefficient of the grown crystal was also measured for UP single crystal.

Introduction. In the recent scenario, an organic nonlinear optical material (NLO) is attracting a great deal of attention due to their potentially high nonlinearity and rapid response in electro-optic modulation, frequency mixing, second harmonic generation and optical parametric oscillation etc over the inorganic NLO material [1-3]. The search for nonlinear optical crystal is, in fact, the search for the “polar crystals” in which the macroscopic properties reflect the internal asymmetric relationship. The structural flexibility of organic chromophores easily modifiable through precise chemical synthesis in view to increase the molecular hyperpolarizability and the possible crafting of chirality centers are remarkable assets compared to the difficulties of the engineering route of inorganic materials, in which the requirements of non-centrosymmetry and high susceptibility have to be accounted [4,5]. Most of the organic nonlinear optical crystals which have low laser damage threshold values, less thermal stability etc., and hence these materials have been limited for device fabrication. In order to overcome these properties, a new class of organic nonlinear material crystal with high laser damage threshold value has been found. In the present investigation, growth, thermal, optical, laser damage threshold dielectric and microhardness have been carried out on the UP single crystal. Experimental. Synthesis, solubility .Commercially available Urea (Merck AR grade 99.5%) and Phosphoric acid (SRL AR grade 99.5% ) were very well dissolved in de-ionized water which was thoroughly mixed using a magnetic stirrer and the mixture was heated at 45°C till a white crystalline salt of UP was obtained. The synthesized salt was further purified by repeated crystallization. The reaction scheme and their chemical structures are illustrated below.

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CO (NH2)2 + H3PO4 CO

(NH2)2+ H3PO4

The solubility of UP in water (Fig. 1). 26 24

Concentration (gm/100 ml)

22 20 18 16 14 12 10 8 6 34

Temperature (C)

Fig. 1. Solubility curve of UP. Crystal growth.The saturated solution was prepared in accordance with the solubility curve. Single crystals of UP were grown from their aqueous solution using the slow evaporation method. The prepared solution was kept in a constant temperature water bath of accuracy of ±0.01 °C. After a span of 19 days, a medium size single crystal with the dimensions of 14 x 5 x 4 mm3 was harvested. The photograph of the grown crystal of UP is shown in Fig 2.

Fig. 2 .Photograph of UP crystal. Characterizations. The grown UP crystals were subjected to X-ray diffraction studies using Bruker kappa APEXII single crystal X-ray difffractometer, using MoKα (λ = 0.71073 A˚ ). The various functional groups of UP crystal were identified by the KBr pellet technique using a Perkin Elmer FTIR spectrometer in the range 4000–450 cm-1. The transmission spectrum of the UP crystal was studied in the range 200–1100 nm by Perkin Elmer spectrometer. The dielectric measurement has been carried out using HIOKI 3532–50 LCR HITESTER instrument. Microhardness measurement of UP crystal was carried out using Leitz-Wetzlar Vickers’ microhardness tester fitted with a diamond pyramidal indenter attached to an optical microscope.The Kurtz and Perry powder technique was employed on UP crystal to measure the second harmonic generation efficiency using Nd:YAG laser. Single X-ray diffraction analysis. The cell parameters of the UP crystal were estimated by single crystal X-ray diffraction analysis and cell parameters are a = 17.3813 Å, b = 7.425 Å, c = 8.9323 Å, V= 1158 Å3, with angle β= α= γ = 90°. [6] The grown crystal belongs to orthorhombic crystal system MMSE Journal. Open Access www.mmse.xyz

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with space group Pbca. It is observed that lattice parameter values and cell volume of UP are in good agreement with the reported values [7]. FTIR spectral studies.The FTIR analysis of UP was carried out between 4000 and 450 cm-1 using Perkin Elmer model spectrometer. The resulting spectrum is shown in figure.The peak at 3778 cm -1 may be assigned to NH asymmetric stretching. The peaks at 3450 and 1662 cm-1 are assigned to OH asymmetric stretching and C=O asymmetric stretching respectively. The peak at 1453 cm-1 is assigned to P=O bending. The C-N asymmetric stretching appears at 1084 cm-1. The peaks at 983,866, 584 and 529 cm-1 were attributed to NCN symmetric stretching, P-O asymmetric stretching, P=O bending and P-O bending vibration respectively. The C-N rocking exhibit at 508 cm-1. Figure 3 shows FTIR spectrum of UP crystal.

Fig. 3. FTIR spectrum of UP crystal. UV-Vis spectral studies UV-Visible transmission spectrum of UP crystal was recorded in the range of 190-900 nm using 0.93 mm thickness crystal sample. UP crystal is active in the UV-Vis region. It has good transparency of about 55% with lower cut-off wavelength 278 nm (Fig. 4).

6(a)

Transmittance (%T)

0 200

300

400

500

600

700

800

900

Wavelength (nm)

Fig. 4. UV-Vis transmission spectrum of UP crystal.

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Dielectric studies. The plates were polished and coated with an electronic grade silver paste, which acts as an electrode. Figure 5 shows the variation of dielectric constant (Îľr) with log frequency. From the plot, it is observed that the dielectric constant is relatively higher at 100 Hz and further decreases with increase in frequency. This effect can be attributed to the effect of charge distribution by mean carrier hopping on defects. At low frequency, the charge on the defects can be rapidly redistributed so that defects closer to the positive side of the applied field become negatively charged, while defects closer to the negative side of the applied field become positively charged. This leads to a screening of the field and overall reduction in the electric field. The high value of dielectric constant at low frequency can be attributed to the lower electrostatic binding strength, arising due to the space charge polarization near the grain boundary interfaces. In accordance with Miller rule, the lower value of dielectric constant at higher frequencies is a suitable parameter for the enhancement of SHG coefficient [8]. The characteristic of low dielectric loss (Fig. 6) with high frequency for the sample suggests that the crystal possess enhanced optical quality with lesser defects and this parameter play a vital role for the fabrication of nonlinear optical devices [9]. 200

313 K 333 K 353 K

180

Dielectric constant

160 140 120 100 80 60 40 20 0 1

Log f(Hz)

Fig. 5. Plot of frequency vs. dielectric constant of UP crystal.

313 K 333 K 353 K

11 10 9

Dielectric loss

8 7 6 5 4 3 2 1 0 -1 2

Log f(Hz)

Fig. 6. Plot of frequency vs. dielectric loss of UP crystal.

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SHG Measurments.The Kurtz and Perry technique was used to find the nonlinear property of the crystal. Microcrystalline KDP material was used as a reference material with UP for SHG measurements. A high intensity Nd:YAG laser beam with input pulse of 6.2mJ as a optical source was allowed onto the powder samples. The second harmonic signal (532nm) 56mV and 78.4mV were obtained through KDP and UP samples. Thus the SHG efficiency of the UP crystal is 1.4 times higher than KDP crystal. This result confirms the non centrosymmetric structure and NLO behavior of the as grown UP crystal. Summary. An organic Urea Phosphoric acid (UP) single crystal has been grown by slow evaporation solution growth technique. The cell parameters of UP single crystal were confirmed by single X-ray diffraction analysis. The presence of functional groups was identified by FT-IR spectral analysis. The UV-Vis spectral studies showed that the UP single crystal has wide transmission window in the entire visible region (300-900 nm). The dielectric property of UP crystal revealed the normal dielectric behaviour.The second order nonlinear coefficient of UP crystal was 1.4 times higher than KDP. Acknowledgment One of the authors (D. Jayalakshmi) is grateful to the University grants commission for financial support under minor research project scheme. References [1] J. Badan, R. Hierle, A. Perigand, J. Zyss, in: Williams (Ed.), “Nonlinear Optical Properties of Organic Molecules and Polymeric Materials”, D.5. Am. Chem. So., Washington, DC, 233(1993). [2] D.S. Chemla, J. Zyss, “Nonlinear optical properties of organic molecules and crystals”, Vol.1, Academic Press, London, 1987. [3] R.W. Munn, C.N. Ironside, “Principles and applications of nonlinear optical materials”, Chapman and Hall, London, (1993) [4] S.R.Marder, J.W.Perry, W.P.Schaefer, Science 245, 626 (1989) [5] S.R.Marder, J.W.Perry, W.P.Schaefer, J.Chem.Phys. 2, 985 (1992). [6] S.A.Martin Britto Dhas, M.Suresh, G.Bhagavannarayana, S.Natarajan, J.Crystal Growth. 309 (2007) 48-52. [7] G. Smith, Urs D. Wermuth, Acta Cryst. C66 (2010) o5-o10. [8] Miller C. Appl. Phys. Lett 1964;5: 17-19. [9] Balarew C, Duhlew R. J. Solid State Chem 1984; 55:1-6. Cite the paper N. Hema, R. Usha, D. Shalini, V. Revathi Ambika, D. Jayalakshmi (2017) Growth, Nonlinear, Dielectric Studies on Urea Phosphoric Acid (UP) Single Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.77.39.252

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Optical, Thermal and Electrical Studies on L-Malic Acid Doped ADP Single Crystals for Non-Linear Optical Application18 S. Arulmani1, K. Deepa2, N. Indumathi1, M. Victor Antony Raj2, S. Senthil1, a 1 – Department of Physics, Govt. Arts College for Men (Autonomous), Nandanam, Chennai, India 2 – Department of Physics, Loyola College, Chennai, India a – ssatoms@yahoo.co.in DOI 10.2412/mmse.30.76.146 provided by Seo4U.link

Keywords: PXRD, FT-IR, NLO studies, UV-visible, TGA/DTA, dielectric studies.

ABSTRACT. Ammonium Dihydrogen Phosphate (ADP) is one of the most popular crystals used for nonlinear optical

(NLO) applications. ADP crystal is of more appeal due to its piezo-electric property. ADP crystals attract more interest because of their unique nonlinear optical, dielectric and anti-ferroelectric properties. The L-Malic acid doped ADP (LMADP) single crystals were grown by slow evaporation method at room temperature. The Crystalline nature of the grown LMADP crystal has been studied by powder XRD analysis. A Fourier transform infrared (FT-IR) study confirms the functional groups of the crystals. The second harmonic generation efficiency of the crystals was determined by NLO studies. The UV-visible study confirms the wide optical transmittance window for the doped crystals imperative for optoelectronics applications. TG/DTA analyses were carried out to characterize the melting behavior and stability of the title compound. The electrical properties of the grown crystal have been analyzed by dielectric constant and dielectric loss with frequency.

Introduction. Ammonium dihydrogen phosphate (ADP) is a well-known anti-ferroelectric crystal. The study of ADP crystal is very interesting in view of the dielectric, piezo-electric and optical properties. Growth and studies of ammonium dihydrogen phosphate (ADP) crystal is a favorite topic to researchers because of its unique properties and wide applications. Single crystals of ADP are used for frequency doubling and frequency tripling of laser systems, optical switches in inertial confinement fusion and acoustic-optical devices [1,2]. ADP has been the subject of a wide variety of investigations over the past decades. Reasonable studies have been done on the growth and properties of pure ADP. In the light of the research work being done on ADP crystals, to improve the properties, the present work focuses on L-malic acid as a dopant in ADP and this is expected to enhance the nonlinearity of the crystal. In the last decades, many researchers have tried to found varieties of new NLO materials for laser applications [3]. Nonlinear optical (NLO) materials play a major role in information technology and industrial applications. L-Malic acid doped with ADP will be of special interest as a fundamental building block to develop complex crystal with improved NLO properties. The grown crystals were characterized by PXRD, FTIR, TG/DTA, Dielectric studies, UV-vis spectroscopy and NLO Studies. Experimental Procedure. L- Malic acid of 0.3% has been doped with pure ADP (Ammonium dihydrogen phosphate). The calculated amount of salts was dissolved in double dissolved water. This solution was then stirred well for more than four hours and filtered using Whatmann filter paper. The pH value of the reaction mixture was monitored. It was porously sealed and placed in a dust free atmosphere for slow evaporation at room temperature. Optically transparent crystals were harvested within 30 days. The photograph of as grown doped LMADP crystal is shown in Fig .1. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Fig. 1. As grown single crystal of LMADP. Result and Discussion. Powder X-ray Diffraction Analysis. X-ray diffraction technique is a powerful tool to analyze the crystalline nature of the materials. Powder X-ray diffraction analysis was carried out by using XPERTPRO X-Ray diffractometer with CuKÎą radiation (Îť=1.5406 Ă&#x2026;). The samples were scanned over the range 10-70Â° as shown in the Fig. 2. The cell parameter values for LMADP are a=b=7.406Ă&#x2026;, c=7.526Ă&#x2026; with the angles đ?&#x203A;ź = đ?&#x203A;˝ = đ?&#x203A;ž = 90Â°. The present result is in close agreement with the reported results [4]. The structure of LMADP crystal is tetragonal. The sharp and well defined peaks at specific 2Ć&#x; values indicate the high crystalline nature of the crystal.

Fig. 2. Powder XRD pattern of LMADP crystals. FT-IR Analysis. FT-IR spectra of LMADP crystal were recorded in range of 450-4000cm-1 by KBr PELLET technique. The functional groups of L-Malic acid doped with ADP crystals have been identified and it was shown in Fig 3. The characteristic peaks of functional groups of LMADP are observed at 3236, 1167, 973 [5]. The broad band in the high energy regions is due to the O-H vibration of water, P-O-H group and N-H vibration of ammonia. The peaks at 1101 and 908 cm-1 represent PO-H vibrations. The PO4 vibration gives their peaks at 547 and 499 cm-1. The bending vibration of water gives it peak at 1646 cm-1 in IR. The peak at 1402cm-1 is due to bending vibrations of ammonium. The vibrational band at 3245 cm-1 was also assigned to the vibration of N-H band. The C-O stretching mode of vibration and O-H in-plane bending modes of vibration is observed at 1213 cm-1 [6]. The PO4 vibration of the parent is shifted from 611to 481 cm-1, which was confirm by the presence of L-Malic acid on the lattice of ADP crystals.

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Fig. 3. FT-IR spectral analysis of LMADP Crystal. SHG Analysis. Kurtz and Perry techniques [7] were employed to measure the SHG efficiency of the grown crystals in reference with the pure KDP. In the measurement, Q-switched Nd:YAG laser of wavelength 1064nm of peak power 2.35 mJ, pulse duration 8 ns and repetition rate 10Hz was used. Output intensity of SHG gives relative values of NLO efficiency of the material. The output energies from the grown sample and reference KDP are found to be 21.2 mW and 19.6 mW respectively. It is found that the SHG efficiency is 1.08 times greater than that of standard KDP. Optical Absorption Studies. The UV-Vis spectrum of LMADP crystals were recorded using Perkin Elmer UV-Vis spectrometer (Model: Lambda 35) in the wavelength range of 200-900 nm. Optically polished single crystals of thickness 3mm were used for this study. Fig. 4. shows that the absorption spectrum of the grown crystals and the cut-off wavelength is found to be 220 nm. The presence of lower cut off wavelength and the wide optical transmission window range of the materials possessing NLO activity. The good transmittance property of the crystal in the entire visible region ensures its suitability for second harmonic generation application [8]. The optical band gap energy value is found to be 4.68 eV from Fig. 5.

Fig. 4. UV-vis absorption of LMADP Crystal.

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Fig. 5. UV-vis band gapof LMADP Crystal. Thermal Analysis. The thermal behavior of LMADP was studied by the Thermogravimetric (TG) and differential thermal analyses (DTA) recorded using PerkinElmer Diamond TG/DTA instrument. Differential thermogram analysis (DTA) and Thermogravimetric analysis (TGA) give information regarding phase transition and different stages of decomposition of the crystal system. The thermal analyses are used to found out the weight loss (TGA), melting and decomposition point (DTA) of the grown LMADP single crystal. The DTA curve of LMADP has a major endothermic peak at 208 0 C. It coincides with the weight loss in the TGA trace. The endothermic peak at 2080 C represents the melting point of the compound. Another important observation is that, there is no phase transition and color change till the material melts and this enhances the temperature range for the utility of the crystal for NLO applications. It is observed from the literature that the presence of ‘‘higher decomposing temperature doping increases the thermal stability of the compound [9].

Fig. 6. TG-DTA spectrum of LMADP Crystal. Dielectric Studies. The dielectric analysis is an important characteristic that can be used to fetch knowledge based on the electrical properties of a material medium as a function of temperature and frequency. Based on this analysis, the capability of storing electric charges by the material and capability of transferring the electric charge can be assessed. Dielectric properties are correlated with electro optic property of the crystals particularly when they are non-conducting materials [10]. The value of dielectric constant decreases with the increase in frequency and becomes constant at higher frequency. The high value of dielectric constant in the low frequency region may be due to the contribution from all four polarizations namely, electronic, ionic, orientation and space charge polarization and its low value at higher frequency may due to the loss of signiﬁcance of these polarizations gradually. MMSE Journal. Open Access www.mmse.xyz

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Fig. 7. Dielectric constant Vs Log f of LMADP Crystal.

Fig. 8. Dielectric loss Vs Log f of LMADP Crystal. Summary. A novel organic single crystal of LMADP was grown from aqueous solution by the slow evaporation method. The crystal structure was confirmed by single-crystal XRD analysis and the FTIR trace reveals the presence of functional groups. The UV cut-off wavelength of LMADP crystal is found to be 220 nm and the band gap is 4.687 eV. TGA/DTA confirms that the sample is stable up to 208 °C. The SHG efficiency of LMADP crystal is 1.08 times greater than that of the KDP. The low dielectric constant and dielectric loss of LMADP at higher frequencies show that the material is a more suitable candidate for nonlinear optical application. References [1] D. Xu and D. Xu, “Chemical Bond Simulation of KADP Single-Crystal Growth,” Journal of Crystal Growth, Vol. 310, pp, 7-9, 2008. DOI: 10.1016/j.jcrysgro.2007.12.008. [2] Delcie Zion, Shyamala Devarajan, Thayumanavan, Arunachalam, Dielectric and Optical Characterization of Boron Doped Ammonium Dihydrogen Phosphate, Journal of Crystallization Process and Technology, Vol. 3, pp, 5-11, 2013. DOI: 10.4236/jcpt.2013.31002 [3] Redrothu Hanumantharaoa, S. Kalainathana, G. Bhagavannarayanab, U. Madhusoodanan, An extensive investigation on nucleation, growth parameters, crystalline perfection, spectroscopy, thermal, optical, microhardness, dielectric and SHG studies on potential NLO crystal – Ammonium Hydrogen L-tartarte, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 103, pp, 388–399, 2013. DOI: 10.1016/j.saa.2012.10.044. [4] Suresh Sagadevan , Investigation on the Optical Properties of Nonlinear Optical (NLO) Single Crystal: L-Valine zinc hydrochlorideAmerican Journal of Optics and Photonics Vol. 2(3), pp, 24-27, 2014. DOI: 10.11648/j.ajop.20140203.11.

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[5] R.N. Shaikha, Mohd. Anisa, M.D. Shirsatb, S.S. Hussaini, Study on optical properties of L-valine doped ADP crystal Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol.136, pp, 1243–1248, 2015.DOI:10.1016/j.saa.2014.10.009. [6] A. Silambarasan, P. Rajesh, P. Ramasamy, Study on structural, morphological, optical and thermal properties of guanidine carbonate doped nickel sulfate hexahydrate crystal ,Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , Vol. 134, pp, 345–349, 2015. DOI:10.1016/j.saa.2014.06.096 1386-1425. [7] N.R. Rajagopalan, P. Krishnamoorthy, K. Jayamoorthy a, Muthu Austeria d, Bis (thiourea) strontium chloride as promising NLO material: An experimental and theoretical study, Karbala International Journal of Modern Science. Vol. xx, pp, 7-9, 2016. DOI: 10.1016/j.kijoms.2016.08.001 2405-609X. [8] R.N. Shaikha, Mohd. Anisa, M.D. Shirsatb, S.S. Hussaini,Study on optical properties of L-valine doped ADP crystal, Spectrochimica Acta Part aMolecular and Biomolecular Spectroscopy, Vol. 81, pp, 270– 275, 2011.DOI:10.1016/j.saa.2011.06.009. [9] B.C. Hemaraju, M.A. Ahlam, N. Pushpa, K.M. Mahadevan, A.P. Gnana Prakash, Synthesis, growth and characterization of a new promising organic nonlinear optical crystal: 4–nitrophenyl hydrazine, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 15, pp, 1386-1425, 2015.DOI: -10.1016/j.saa.2015.07.031. [10] S. Boomadevi, H. P. Mittal and R. Dhansekaran, “Synthe- sis, Crystal Growth and Characterization of 3-Methyl 4- Nitropyridine 1-Oxide (POM) Single Crystals,”Journal of Crystal Growth, Vol. 261, pp, 55-62, 2004. DOI:10.1016/j.jcrysgro.2003.09.005. Cite the paper S. Arulmani, K. Deepa, N. Indumathi, M. Victor Antony Raj, S. Senthil (2017). Optical, Thermal and Electrical Studies on L-Malic Acid Doped ADP Single Crystals for Non-Linear Optical Application. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.30.76.146

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Thermal and Dielectric Properties Of L-Malic Acid Doped KDP Single Crystals19 A. Venkatesan1,2, S. Arulmani3, E. Chinnasamy3, S. Senthil3, M.E. Rajasaravanan2, a 1 – Department of Physics, Arignar Anna Govt. Arts College, Villuppuram, India 2 – Department of Physics, Government Arts College, Salem, Indida 3 – Department of Physics, Govt. Arts College for Men (Autonomous), Nandanam, Chennai - 600 035. a – merajasaravanan@gmail.com DOI 10.2412/mmse.24.24.878 provided by Seo4U.link

Keywords: PXRD, FT-IR, FT-Raman, NLO studies, dielectric studies, UV-visible, TGA/DTA.

ABSTRACT. Potassium Dihydrogen Phosphate (KDP) is a popular nonlinear optical materials that is widely used in the field of nonlinear optics for the frequency conversion processes. Optically good quality L-Malic acid doped KDP (LMKDP) crystals have been grown by slow evaporation method at room temperature. The crystallinity of the LMKDP crystals has been studied by powder XRD analysis. The presence of the functional group for LMKDP crystals are qualitatively analyzed from FTIR and FT-RAMAN spectrum. The second harmonic generation (SHG) efficiency was measured by using Kurtz powder technique. The dielectric behavior of grown crystals has been studied in the frequency range from 50 Hz to 50MHz. UV–visible absorption spectrum was recorded to study the optical transparency of grown crystal. Thermogravimetric analysis (TG) and differential thermal analysis (DTA) were used to study the thermal properties of the grown crystal.

Introduction. In this modern era of information and technology with fast and high data storage capacity, data retrieving, processing and transmission demands the search of new NLO materials with unique physical properties. Hence, there is a great demand for synthesize the new NLO materials and grow their single crystals. KDP is among the most widely used NLO material. Potassium dihydrogen phosphate (KDP) crystals have created considerable interest because of its Piezo-electric, electrooptic, nonlinear optical properties and its extensive application in X-ray monochromators [1]. In addition to their large NLO response, the advantage of organic materials is that they offer high degree of synthetic ﬂexibility to tailor their optical properties through the structural modiﬁcation and they exhibit high laser damage threshold [2]. In single crystals form, the NLO materials display huge optical nonlinearity, which is of great interest for telecommunication, optical information processing and high optical data storage, etc., [3]. Many methods have been tried to improve the NLO properties of KDP crystal. With the aim of improving the second harmonic generation (SHG) efficiency of KDP, researchers have attempted to modify KDP crystals by doping different types of impurities. The present work, L-Malic acid of 0.2 molar percentages has been doped with KDP material. The grown L-Malic acid doped KDP (LMKDP) crystals were characterized by PXRD, FTIR, FT-RAMAN, NLO, Dielectric studies. Experimental Procedure. In the present work, L-Malic acid of 0.2 molar percentages has been doped with KDP material. The solution was thoroughly stirred for homogenization and then filtered into a borosil beaker using whatmann filter paper. It was porously sealed and placed in a dust free

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atmosphere for slow evaporation technique at room temperature. Single colorless and optically transparent crystals were harvested within 30 days. Results and Discussion Powder X-ray Diffraction Analysis. Powder X-ray diffraction technique is a powerful tool to analyze the crystalline nature of materials. Powder X-ray diffraction analysis was carried out by using XPERTPRO X-Ray diffractometer with Cukα radiation (λ=1.5406 Å). The cell parameter values for LMKDP are a=b=0.634Å, c=0.524Å with the angles α = β = γ = 90°. The samples were scanned over the range 10 - 70°. The sharp and well defined peaks at specific 2θ values indicate the high crystalline nature of the crystal. Powder XRD graph has been shown in the Fig.1.

Fig. 1. Powder XRD pattern of LMKDP crystals. FT-IR and FT-Raman Analysis. FT-IR and FT-Raman spectra of LMKDP crystal were recorded and the spectrum of LMKDP crystals are shown in Fig.2 and Fig.3. An intense band of strong absorption around 1204.67cm−1 and protonated by the carboxyl group (COOH) gives hydrogen bonding [4], which is attributed to O-H stretching vibration for the confirmative group of water on hydration. The functional groups of the LMKDP crystals have been identified by the spectrum. In the high frequency region of IR spectra, the sharp peaks observed at 540.13 cm-1 are described to PO4 stretching vibration in the crystal. The O-H deformation and P=O stretching will be observed in the frequency of 1350.67cm-1. In FTIR the absorption band at 1350.67 cm-1 is due to P-O-H bending vibration in the LMKDP. In Raman studies the sharp peak will be observed at1053.52cm-1 is described to P-O-H stretching molecule in the LMKDP crystals.

Fig. 2. FT-IR spectral analysis of LMKDP Crystal.

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Fig. 3. FT-RAMAN analysis of LMKDP Crystal. SHG Analysis. Nonlinear optical measurements were carried out by using Kurtz powder technique. In order to conﬁrmed the NLO property, the grown crystals were powdered and subjected to Kurtz and Perry powder technique, which is a powerful tool for initial screening of materials for SHG [5]. A Q-switched Nd:YAG laser beam of 1064 nm wavelength with 1.9 mJ/pulse input power, 8 ns pulse width and repetition rate 10Hz was used to estimate SHG efficiency of the grown LMKDP crystals. KDP crystalline powder was the reference material, the output of SHG range was compared and found that the SHG conversion efficiency of LMKDP is 1.4 times greater than that of reference KDP. Dielectric Studies. Every material has a unique set of electrical characteristics that are dependent on its dielectric properties. The variation of dielectric constant and dielectric loss of the sample with frequency is studied at room temperature by H10K1 3532 LCR HITESTER in the frequency range 50 Hz to 50 MHz and is shown in Fig. 4 and Fig. 5. The high value of dielectric constant at high frequency may be due to the presence of all the four polarizations namely space charge, orientation, electronic and ionic. The dielectric characteristic of a crystal is determined by the dielectric constant and dielectric loss. The dielectric constant (ε ′) and dielectric loss (ε ′′) of the sample were calculated using the following equation [6]:

ε ′= c*t/ ε ο A

(1)

ε ′′= ε ′/Q

(2)

Fig. 4. Dielectric constant Vs Log f of LMADP Crystal

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Fig. 5. Dielectric loss Vs Log f of LMADP Crystal. Optical Absorption Studies. The UV-Vis spectrum of LMKDP crystals were recorded by using Perkin Elmer UV-Vis spectrometer (Model: Lambda 35) in the wavelength range of 200-900 nm. Optical transparency range of single crystals plays a very important role in optical technology [7]. UV-Visible techniques are helpful in the investigation of NLO materials making it possible to check, both NLO responses and spectroscopic absorbance in the appropriate wavelength range [8]. Good optical transmittance and lower UV cutoff (219.5 nm) wavelengths are very important properties for the grown crystals [9]. This is one of the most desirable properties of the crystals for the device fabrication. The band gap of the crystal was evaluated by extrapolation of the linear part of the graph and found to be 5.122 eV.

Fig. 6. UV-vis absorption of LMADP Crystal.

Fig. 7. UV-vis band gap of LMADP Crystal.

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Thermal Analysis. The thermal stability of the crystal is a very important factor for potential application. The thermal stability of the title compound was identify by thermogravimetric (TGA) and differential thermal analysis (DTA) studies simultaneously. Thermogravimetric analysis shows that LMKDP is very stable up to 209.49οC and the weight loss starts at this temperature. It is observed from DTA thermogram that an endothermic event begins at 219.14 οC and then sharp peak appears at 240.31οC and the second peak appears at 271.27οC. An endothermic event is observed at 240.31οC which is due to melting of the sample. Good crystalline nature of the title compound is clearly noticeable from the sharpness of the endothermic peak. The sharp endothermic peak 240.31 οC at is due to the decomposition of the sample desired by its DTA analysis and it coincides with the TG curve [10].

Fig. 8. TG-DTA spectrum of LMADP Crystal. Summary. The good-quality single crystals of LMKDP were successfully grown by slow evaporation method at room temperature. XRD studies reveal the tetragonal structure of the grown crystals. FT-IR spectrum conﬁrm the presence of functional group in the grown crystal. The UV–Vis spectra showed that the crystals had a wide optical window, no absorbance and good optical transmittance in the entire visible region. The nonlinear optical studies conﬁrm the SHG property of the grown crystal. The SHG efficiency of LMKDP is 1.4 times greater than that of reference KDP. The electrical property of the grown crystal was observed by the dielectric studies. TGA and DTA thermogram revealed the thermal stability of the materials. References [1] J. J. De Yoreo, A. K. Burnham and P. K. Whiteman, Developing KH2PO4 and KD2PO4 crystals for the world’s most powerful laser. International Materials Reviews, Vol. 47, pp, 3- 113, 2002. DOI: 10.1179/095066001225001085. [2] T. Arumanayagam, S. Ananth, P. Murugakoothan, Studies on growth, spectral, optical and mechanical properties of new organic NLO crystal, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy,Vol.97, pp, 741–745, 2012. DOI:10.1016/j.saa.2012.07.039. [3] Mohd Shkir, Haider Abbas, Physico chemical properties of L-asparagine L-tartaric acid single crystals: A new nonlinear optical material, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 118, pp, 172–176, 2014. DOI: 10.1016/j.saa.2013.08.086. [4] Pedro S. Pereira Silva, M.A. Pereira Gonçalves, Manuela Ramos Silva, José A. Paixão, Structural and nonlinear optical studies of a salt with an octupolar chromophore: Guanidinium cyclopropanecarboxylate, Spectrochimica Acta Part A: Molecularand Biomolecular Spectroscopy, Vol.xx, pp, xx, 2016. DOI: 10.1016/j.saa.2016.04.020.

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[5] C. Sekar, R. Parimaladevi , Effect of KCl addition on crystal growth and spectral properties of glycine single crystals, ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 74, pp, 1160–1164, 2009. DOI:10.1016/j.saa.2009.09.026. [6] Muthaiyan Rajalakshmi, Ravanan Indirajith, Rengasamy Gopalakrishnan, Single Crystal Growth of Lanthanum(III) Molybdate(VI) (La4Mo7O27) Using H3BO3 Flux, Journal of Crystallization Process and Technology, Vol. 4, pp, 39-45, 2014.DOI:10.4236/jcpt.2014.41006. [7] V. Krishnakumar and R. Nagalakshmi, Growth, nonlinear optical, thermal, dielectric and laser damage threshold studies of semiorganic crystal: Monohydrate piperazine hydrogen phosphate Spectrochimica Acta Part A, Vol. 263, pp. 192–202, 2005. DOI:10.1016/j.jcrysgro.2003.10.083. [8] V. Krishnakumar and R. J. Xavier, FT Raman and FT–IR spectral studies of 3-mercapto-1,2,4triazole Spectrochimica Acta Part A,Vol.60. pp, 709–714, 2004. DOI: 10.1016/S13861425(03)00281-6. [9] P. Krishnana, K. Gayathria, G. Bhagavannarayanab, S. Gunasekaranc, G. Anbalagan, Growth, nonlinear optical, thermal, dielectric and laser damage threshold studies of semiorganic crystal: Monohydrate piperazine hydrogen phosphate, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 102. pp, 379–385, 2013. DOI: 10.1016/j.saa.2012.10.004. [10] P. Ilayabarathia, J. Chandrasekaranb, Growth and characterization of L-alanine cadmium bromide a semiorganic nonlinear optical crystals, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 96 pp, 684–689, 2012. DOI: 10.1016/j.saa.2012.07.027. Cite the paper A. Venkatesan, S. Arulmani, E. Chinnasamy, S. Senthil, M.E. Rajasaravanan (2017). Thermal and Dielectric Properties of L-Malic Acid Doped KDP Single Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.24.24.878

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Optical, Thermal and Electrical Characterization of Urea Sulphamic Acid Single Crystals20 E. Chinnasamy1, A.Venkatesan2,3, M.E. Rajasaravanan3, S.Senthil1, a 1 – Department of Physics, Govt Arts College for Men, Nandanam, Chennai, India 2 – Department of Physics, Aringnar Anna Arts College, Villuppurm, India 3 – Department of Physics, Government Arts College, Salem, India a – ssatoms@yahoo.co.in DOI 10.2412/mmse.57.53.259 provided by Seo4U.link

Keywords: single crystal XRD, FT-IR, UV-Vis spectral studies and PL studies, TG/DTA, dielectric studies.

ABSTRACT. Urea Sulphamic acid single crystal was grown by slow evaporation techniques at room temperature. The cell parameters of the grown crystal were determined by single crystal X-ray diffraction analysis. The presence of functional groups in the crystal lattice has been qualitatively determined by FT-IR analyses. Optical characterization were analysed by UV-Vis and photo Luminescence (PL) spectral studies and the band gap energies of the USA single crystals have been calculated. Thermo gravimetric and differential thermo gravimetric analysis (TG/DTA) indicates the thermal stability of the grown crystal. The dielectric properties of the grown crystal have been studied.

Introduction. The search of materials for various device applications has led to discovery of many organic, inorganic and semi organic crystals. The responsibility for the exquisiteness of the crystal is due to their structural simplicity, symmetry and purity. These characteristics endow crystals with unique physical and chemical properties which caused major transformation in the electronics industry [1-2]. Nonlinear Optical (NLO) materials have potential applications in optoelectronics, Second Harmonic Generation (SHG), optical storage, optical communication, photonics, electro optic modulation, optical parametric amplifiers, optical image processing, etc [3]. In recent years more emphasis is given to inorganic materials due to their much matured NLO applications than organic materials and owing to their good transparency, chemical stability, and mechanical properties [4]. Also research into the growth of large single crystals from aqueous solution is currently serving as the important avenue to general progress in understanding many fundamental concepts of crystallization [5]. Hence, in the present work, a systematic study on the growth and characterization of Urea Sulphamic acid (USA) is reported. The grown single crystals have been subjected to single crystal XRD, FTIR, UV-visible and Photoluminescence spectroscopy, TG/DTA and dielectric studies respectively. Experimental Procedure. In the present study, USA crystals were grown by slow evaporation solution growth technique. Urea and Sulphamic acid were taken in equimolar ratio and dissolved in Millipore water. The solution was stirred up to saturation state. The solution was filtered and covered with dust free polyethylene sheet then placed at room temperature [6]. After a period of 15 to 20 days, good quality and highly transparent Urea Sulphamic acid (USA) seed crystals has been grown and the good quality seed crystals are allowed to grow and the crystals of size 13x5x4 mm3 was harvested. The photograph of the as grown single crystal is shown in Fig.1

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Fig. 1. Photograph of as grown USA Single Crystal. Results and Discussion Single Crystal X-Ray Diffraction. Single crystal X-ray diffraction analysis of USA crystal was carried using an Enraf Nonius CAD4 single crystal X-ray diffractometer with an incident CuKα radiation, and the calculated lattice parameter values are a= 8.076 Å, b= 8.098 Å, c= 9.218 Å, α=β=γ=90° and V = 602.8 (A3). The lattice parameter values show that the grown USA crystal belongs to orthorhombic structure, which is confirmed with the reported values. FT-IR Spectral Analysis. The FTIR spectroscopy study is effectively used to identify the functional group present in the material. The FTIR spectrum for USA is recorded using BRUKKER IFS 66V spectrometer by KBr pellet technique in the range 400-4000 cm-1 and is show in Fig. 2. The FTIR spectrum of Urea Sulphamic Acid seems to be complex because of various functional groups present in the crystal. The functional group assignments for USA is summarized in Table 1.

Fig. 2. FT-IR Spectrum of Grown USA Crystal. UV-Visible Absorption Spectrum. The absorption spectra of USA crystal is measured in the wavelength range 200-800 nm using Philips PV8700 UV-visible scanning spectrometer. The recorded absorption spectrum is show in Fig.3. It is observed that the, crystal have good transparency window in the entire visible and IR region. The lower cut off wavelength is observed at 254 nm [7]. The optical band gap is obtained by plotting the graph between hυ and (αhυ) 2 and is shown in Fig.4. From the Tauc’s plot, the optical energy band gap is determined as 4.74eV.

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Table. 1. Fundamental Vibrational Assignments of USA crystal. Wave number

Assignment

â&#x2C6;&#x2019;1

(cm ) 3096

Degeneracy. NH3+ stretching

2877

Symmetric. NH3+stretching

1535

Degeneracy. NH3+ deformation

1440

Symmetric. NH3+ deformation

1239

Degeneracy.SO3- stretching

1061

Symmetric. SO3- deformation

683

N-S Stretching

529

Degeneracy.SO3- deformation

Fig. 3. UV absorption spectrum of USA crystal.

Fig. 4. Optical Band gap of USA crystal. Photoluminescence Analysis. Aromatic compounds or the molecules with multiple conjugated double bonds are expected to give high degree of resonance stability and can be expected strong fluorescence. The emission spectrum has been recorded at room temperature by exiting the molecules with wavelength of 362 nm. The emission spectrum is shown in Fig.5. Strong emission from green to red is observed with three peaks at 503, 609 and 749 nm for this excitation. The property of having strong emission in this range may lead to potential application of this material in optoelectronic device [8]. MMSE Journal. Open Access www.mmse.xyz

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Fig. 5. Emission spectrum of grown USA crystal. Thermal Analysis. The thermal stability and physiochemical changes of USA crystal were analyzed by recording the TG–DTA spectrum as shown in Fig.6. It reveals that USA is thermally stable upto 191.0°C and after this the sample undergoes appreciable weight loss. The change in weight loss confirms the decomposing nature of USA sample. The DTA spectrum confirms the melting point of the sample through a sharp exothermic peak at 191.0°C. Moreover, the endothermic peak at 409.4°C reveals the volatile nature of the sample. After that no sharp peak was observed, which confirms that the material is thermally stable up to 409.4°C.

50.00

110.0

40.00

100.0

223.4Cel 41.86uV

75.5%

90.0 30.00

191.0Cel 24.12uV

80.0

20.00

70.0

60.0

50.0

TG %

DTA uV

10.00

0.00 40.0

-10.00

30.0

20.0 -20.00 10.0 -30.00 0.0

409.4Cel -32.33uV

-10.0

-40.00 50.0

100.0

150.0

200.0

250.0

300.0 Temp Cel

350.0

400.0

450.0

500.0

Fig. 6. TG-DTA spectrum of USA single crystal. Dielectric Studies. Variations in dielectric constant and dielectric loss as a function of room temperature and frequency are shown in Fig. 7a and 7b. In Fig.7a, it is seen that the value of dielectric constant is found to increase with temperature and it becomes independent of frequency at higher frequency region. The decrease in dielectric constant of USA crystal at low frequencies may be attributed to the contribution of the electronic, ionic, orientation and space charge polarizations which depend on the frequencies [9]. The low value of dielectric loss at high frequencies suggests that the sample possess enhanced optical quality with lesser defects and this parameter is of vital importance for NLO applications [10].

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b) Fig. 7. a) Dielectric constant for USA crystal, b) Dielectric loss for USA crystal Summary. Good optical quality single crystals of USA have been grown from slow evaporation technique. The crystallinity of the grown sample has been confirmed by X-ray diffraction analysis. Various functional groups present in the grown crystal have been identified by FTIR analysis. The optical transparency has been revealed by UV-visible study and thermal stability has been confirmed by thermal analysis. The low dielectric constant and dielectric loss of USA at higher frequencies show that the material is a more suitable candidate of nonlinear optical application. References [1] N .Vijayan, G Bhagavannarayana, R Ramesh Babu, R Gopalakrishnan, KK Maurya, P Ramasamy, “Assessment on third order non linearity and other optical analyses of L-Asparagine Monohydrate single crystal: An efficient candidate for harmonic conversions” Spectrochimica Acta Part A , Vol. 6, pp. 1542-1546, 2006, doi.org/10.1016/j.saa.2015.05.051 [2] R. Raja, S. Seshadri, R.R. Saravanan, “Growth and characterization of inorganic non linear optical Barium Calcium Borate (BCB) crystal” Materials Letters, Vol. 125, pp. 916-919, 2014, doi.org/10.1016/j.matlet.2016.04.208 [3] A.K. Dharmadhikari, B. Roy, S. Roy, J.A. Dharmadhikari, A. Mishra, G.R. Kumar, “Crystal growth, spectral, structural, optical and thermal properties of semi-organic single crystal: Tetrakis (thiourea) cadmium (II) nitrate” optics, Vol.235, pp. 195-200, 2004, doi.org/10.1016/j.ijleo.2015.08.031 [4] T.M. Kolev, D.Y. Yancheva, S.I, “Structure, growth and characterization of picolinium perchloratesingle crystals A” Optics, Vol. 14(8), pp.799-805, 2004,doi.org/10.1016/j.ijleo.2016.140

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[5] Valluvan R, Selvaraju K et al, “Growth and characterisation of sulphamic acid single crystal” Material Chemistry and Physics, Vol. 97(1),pp. 81-84, 2006. doi.org/10.1016/j.saa.2007.07.042 [6] M.Lenin, N. Balamurugan, and P.Ramasamy, “Growth of TGS crystals using uniaxially solutioncrystalliization method of Sankaranaryanan-Ramasamy” Crystal Research and Technolgy, Vol.42, pp.151-156, 2007, doi.org/10.1016/j.matlet.206.07.184 [7] Babu R R, Ramesh R.Growth , “structural,spectral, mechanical and optical properties of pure and metal ions doped Sulphamic acid single crtystals”, Spectrochimica Acta Part A, Vol .76(5), pp 470475 ,2010, doi.org/10.1016/j.jcrysgro.2016.10.071 [8] N. Mansour, A.Momeni, R.Karimzadeh, M. Amini, “Photoluminescence analysis of colloidal silicon nanocrystals in DMSO: contribution of surface states emissions”, Laser Physics, Vol .24, pp.16-18, 2014, doi.org/10.1016/j.saa.2014.11.086 [9] M.A. Gaffar, A. Abu El-Fadl, S. “Bin Anooz, Influence of strontium doping on theindirect band gap and optical constants of ammonium zinc chloride” Optics, Vol. 327, pp. 43-54, 2015, doi.org/10.1016/j.ijlo.2015.11.189 [10] M.R. Jagadeesh, H.M.S. Kumar, R.A. Kumari, “Crystal Growth and Characterization of a New Nlo Crystal: Urea 2- Furoic Acid,” Optik, Vol. 126, pp. 4014-4018, 2015, doi.org/10.1016 / j.ijleo.2015.07.190 Cite the paper E. Chinnasamy, A. Venkatesan, M.E. Rajasaravanan, S.Senthil (2017). Optical, Thermal and Electrical Characterization of Urea Sulphamic Acid Single Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.57.53.259

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Crystal Growth, Spectral and Optical Studies of 2-Aminoanilinium Benzoate Single Crystal21 I. Md. Zahid1, C. Amirtha Kumar1, R. Mohan Kumar1,a 1 – Department of Physics, Presidency College, Chennai-600 005, India a – mohan66@hotmail.com DOI 10.2412/mmse.59.74.247 provided by Seo4U.link

Keywords: growth from solution, X-ray diffraction, nonlinear optics.

ABSTRACT. The proton transfer or H-bonded complex of 2-aminoanilinium benzoate (OPDB) was synthesized from O-phenylenediamine as donor and benzoic acid as acceptor. OPDB crystals were grown by solution growth technique. The cell parameters and crystalline perfection of the grown crystal were studied by single crystal and powder X-ray diffraction analyses. The title compound was classified into orthorhombic crystal system with non-centrosymmetric P212121 space group. FTIR spectral analysis revealed the existence of functional groups and their corresponding vibrational modes have been assigned. The optical transmission properties of the crystal were studied by UV–Vis spectral analysis. Laser induced damage threshold of the grown crystal was estimated using Nd:YAG laser source. The second harmonic generation efficiency of the grown crystal was studied by Kurtz-Perry test.

Introduction. Current research in nonlinear optics (NLO) is at the forefront because of its importance in providing the key functions of frequency shifting, optical modulation, optical switching and optical memory for emerging technologies in the areas such as telecommunication, signal processing, and optical interconnections. Also organic nonlinear optical materials are attracting a great deal of attention towards such key functions in comparison with their inorganic counterparts [1,2]. One of the main advantages of organic materials is that they permit one to modify the chemical structure with large physical structural diversities desired for required NLO properties. In addition to the requirement for linear and nonlinear optical properties, high priority is given to crystal structures which belong to non-centrosymmetric class for the application of quadratic nonlinear optical effects and crystals having active SHG efficiency [3]. The second harmonic generation is a nonlinear optical effect that occurs when laser radiation strikes the surface of a material and a fraction of incident lights frequency is doubled [4,5]. In recent years, much effort has been directed towards the design and development of highly efficient organic NLO materials that promotes non-centrosymmetric crystal packing enabling easier and faster bulk crystal growth. Among the various classes of organic materials, amino derivative crystals constitute a family in which aminoanilinium coordination compounds has shown wide range of NLO applications. Interesting potentiality of crystals having orthorhombic system so that it exhibits optical nonlinearity. The pioneering strategy of such co crystallization process was proposed by Cara C.Evans and coworkers [6]. In the present investigation the growth, spectral and optical properties of 2-aminoanilinium benzoate (OPDB) crystal has been studied and results are presented. Experimental Material Synthesis and Crystal Growth. 2-aminoanilinium benzoate (OPDB) was synthesized fromO-phenylenediamine (C6H8N2.,10.81 g) as donor and Benzoic acid (C7H6O2.,12.21 g) as acceptor by dissolving in 100 ml of ethanol. The solution was allowed to stir for 6 hr and then filtered. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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The filtered saturated solution was covered by using polythene sheet with single perforation at the center of the beaker for controlled evaporation and allowed to evaporate in the room temperature. In a period of two weeks, colorless block-shaped crystal of the title compound was harvested. The synthesis scheme and photograph of as grown crystal is shown in Fig. 1(a) & (b).

Fig. 1(a) Synthesis scheme of OPDB.

Fig. 1(b) Photograph of as grown OPDB crystal.

Results and Discussion X-ray Diffraction Analyses. The crystallographic lattice parameters of the grown OPDB crystal were determined using Bruker Kappa APEXII CCD Single Crystal X-Ray Diffractometer and it shows that OPDB crystal belongs to orthorhombic crystal system with non-centrosymmetric P212121 space group. The estimated cell dimension are a = 6.0218(7) Å, b = 12.261 (1) Å, c =16.637 (4) Å , V = 1224.0 (5) Å3and it agree very well with the reported data [6]. The crystal was then grounded finely and subjected to powder X-ray diffraction. The PANalytical X’Pert Powder XRD system was used to record reflections from various planes and the hkl values were determined using the inbuilt Highscore plus program. From the obtained powder X-ray diffraction spectrum (Fig.2), the presence of well-consistent Bragg peaks at specific 2θ angles confirmed the crystallinity of the grown crystal.

Fig. 2. Powder XRD pattern of OPDB crystal. FT-IR Spectral analysis. The infrared (IR) spectrum was recorded using JASCO FTIR 410 spectrometer (4000–450 cm-1). KBr pellet technique was used for recording the infrared spectrum. The assignments have been made on the basis of band position, shape and intensity in correlation with the vibrational bands of structurally related molecules. The presence of aromatic ring in the prepared compound was confirmed by following the IR absorption frequencies and the obtained spectrum is shown in Fig.3. The broad peak appeared in the range of 3400-3600 cm-1 shows the presence of hydrogen bonded –OH group. The carbonyl stretching observed from the peak at 1645 cm-1. The NH- bending of the amino group is affirmed by the peak appeared at 1589 cm-1. The peaks MMSE Journal. Open Access www.mmse.xyz

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observed at 1498 cm-1 and 1371 cm-1 are due to aromatic C-H bending and stretching. The sharp peak obtained at 717 cm-1 is due to C-H rocking vibration. The peaks corresponding to aromatic C=C and C-C vibrations appeared at 1165 and 650 cm-1. Thus, the FT-IR spectrum confirmed the presence of synthesized compound as O-phenylenediamine benzoate and its characteristic vibrational frequencies are summarized in Table 1.

Fig. 3. Infrared spectrum of OPDB. Table 1. Infrared vibrational spectral assignments of OPDB. υ IR(cm-1)

Assignments

3400-3600

hydrogen bonded –OH group

1645

carbonyl stretching

1589

NH- bending of the amino group

1498 and 1371

aromatic C-H bending and stretching

717

C-H rocking vibration

1165 and 650

aromatic C=C and C-C vibrations

UV visible transmission spectral studies. The transmission spectrum of OPDB crystal was recorded using T90+Model Spectrometer in the wavelength range 190-900 nm. Fig.4 shows the UVTransmission spectrum of the OPDB crystal. The higher transparency of the crystal, in the visible region is an important property for any nonlinear optical crystal for device fabrication. The cutoff wavelength was observed at 290 nm for the as grown OPDB crystal and found suitable for optoelectronic applications. Band gap energy (E g) estimation illustrated about the conduction behavior of grown crystal. The band gap value of the material is very closely related to the material’s atomic and electronic band structure. It was calculated using the relation. Eg= hc/λ

(1)

where h is the Planck’s constant, c is the velocity of light and λ is the cut-off wavelength for OPDB.

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The forbidden energy band gap (Eg) for the OPDB crystal was found to be 4.26 eV. Hence, the good transparency combined with low cutoff wavelength makes OPDB suitability for the nonlinear applications

Fig. 4. Uv –vis transmission spectrum of OPDB. Second harmonic generation test. The NLO property of the grown OPDB crystal was studied by Kurtz–Perry powder technique with KDP crystal as reference material. Finely powdered crystal of OPDB was densely packed in a micro-capillary tube of uniform bore. The second harmonic generation (SHG) measurement was carried out using 1064 nm Q-switched mode locked Nd:YAG laser. The pulse width of 8 ns and10 Hz repetition rate with pulse energy of 2.8 mJ/pulse laser was made to fall normally on the sample cell. An intense green light (λ = 532 nm) emission from the sample was detected by a photomultiplier tube which confirmed the second harmonic property of OPDB crystal. KDP powdered sample with identical size was used as reference material in the SHG measurement. The SHG output signal voltages of OPDB and KDP were measured to be 252 mV and 120 mV respectively. Thus, SHG efficiency of O-phenylenediamine benzoate was found to be 2.1 times higher than that of KDP crystal. Laser damage threshold. One of the decisive criteria for a NLO crystal to perform as a device is its resistance to laser damage, since high optical intensities are involved in nonlinear processes. The multiple shot Laser damage threshold measurement was carried out for OPDB crystal using Nd:YAG laser system, which delivered laser pulses at 532 nm having pulse width 6 ns and repetition rate 10 Hz. The energy density was calculated using the relation, Power density P(d)=E/τA

(2)

where E is the input energy (mJ), τ is the pulse width (ns) and A is the area of the circular spot size. For OPDB crystal, the multiple shot laser damage energy density obtained from the Q-switched Nd:YAG laser was found to be 5.98 GW/cm2. It was found that the laser damage threshold value of OPDB crystal is higher than standard potassium dihydrogen phosphate (KDP) crystal (0.20 GW/cm2). Summary. Nonlinear optical 2-aminoanilinium benzoate single crystals were grown by slow evaporation method. The crystalline perfection and lattice parameters of the grown crystal were examined by X-ray diffraction studies. The modes of vibration molecule groups present in the MMSE Journal. Open Access www.mmse.xyz

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compound were confirmed by FTIR spectral analysis. The transmission percentage, lower cutoff wavelength, and optical band gap energy (đ??¸đ?&#x2018;&#x201D;) of the grown crystal were estimated by UV-Vis spectral analysis. The second harmonic generation efficiency of the material was found to 2.1 times higher than that of standard KDP crystal. The surface laser damage threshold value for OPDB crystal was found to be 5.98 GW/cm2, which will be useful for optical applications. References [1] P.N.Prasad, D.J.Williams, Introduction to Nonlinear Optical Effects in Organic Molecules and Polymers, Wiley, New York, 1991. [2] D.S.Chemla, J.Zyss, Eds. Nonlinear Optical Properties of Organic Molecules and Crystals; Academic Press, NewYork, 1987. [3] P.Vijayakumar, G.Anandha Babu, P.Ramasamy, Synthesis, crystal growth and characterization of nonlinear optical organic crystal: p-Toluidinium p-toluene sulphonate, Materials Research Bulletin 47 (2012) 957â&#x20AC;&#x201C;962, doi: 10.1016/j.materresbull.2012.01.011 [4] N. Vijayan, R. Babu, R. Gopalakrishnan, P. Ramasamy, growth and characterization of Benzimidazole single crystals: a nonlinear optical material, J. Cryst. Growth 262, 2004, 490498.DOI: 10.1016/j.crysgro.2003.08.082 [5] H. Nakatani, W.R. Bosenberg, L.K. Cheng, Appl. Phys. Lett. 53 , 1988 , 2587-2591. DOI:10.1063/1.100535 [6] Cara. C. Evans, M. Bagieu- Beucher, R. Masse, J. F. Nicoud, Chem. Mater. 10, 1998, 847-854. DOI:10.1021/cm970618. Cite the paper I. Md. Zahid, C. Amirtha Kumar, R. Mohan Kumar, (2017 Crystal Growth, Spectral and Optical Studies of 2Aminoanilinium Benzoate Single Crystal, Vol 9. Doi 10.2412/mmse.59.74.247

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Synthesis, Vibrational Spectroscopy, Thermal Analysis, Non-Linear Optical Properties and DFT Calculation of a Novel L-Phenylalanine Maleic Acid Single Crystals22 K. Deepa1, J. Madhavan1,a 1 – Department of physics, Loyola College, Chennai-600034, India. a – kdeepasen@gmail.com DOI 10.2412/mmse.78.8.744 provided by Seo4U.link

Keywords: crystal growth, DFT, HOMO-LUMO, FTIR, UV, TG/DTA, SHG.

ABSTRACT. Optically good quality new crystal of L-Phenylalanine maleic acid (LPM) was grown by slow evaporation technique. The crystalline nature of grown crystal is confirmed by X-ray diffraction analysis. Density functional theory (DFT) computations using (B3LYP) level with 6-31G (d,p) basis set gives optimized structure parameters of LPM molecule. Molecular energy gap of LPM was found by HOMO-LUMO analysis. Theoretically calculated vibrational frequencies are compared with experimentally obtained FT-IR frequencies. Optical absorption spectrum was recorded for the given crystal. Thermal stability and SHG studies were carried out for the grown crystal.

Introduction. Nonlinear optical (NLO) materials are active elements for optical communications, optical switching, optical mixing and electro-optic application [1]. Combination of amino acid with an organic compound has been proposed as a new candidate for NLO application, which crystallizes in non centrosymmmetric space group. The proton donor carboxyl group (-COO) and the proton acceptor amino (-NH2) group present in the amino acid contribute some physiochemical properties. The Density functional theory (DFT) calculation has now become the preferred method for understanding and predicting structure and reactivity in complex chemical system. DFT calculation along with vibrational spectral analysis is used as a promising tool to display a significant number of molecular properties of NLO materials [2]. Maleic acid forms crystalline maleate with various organic molecules through specific hydrogen bonding and π-π* interactions. Which exhibit high value of second order polarizability [3]. L-Phenylalanine is an essential protein amino acid, which is used by the body to build neurotransmitter. A sequence of second order NLO active materials composed of L-phenylalanine have been synthesized, such as, L-phenylalanine benzoic acid [4], LPhenylalanine nitric acid [5]. In the present work deals with the experimental and theoretical investigation of L-Phenylalanine maleic acid (LPM) single crystal. Synthesis and crystal growth. High purity L-phenylalanine and maleic acid were taken in 1:1 molar ratio and dissolved in deionized water. The synthesized salt is purified by successive recrystallization process. After attaining the saturation, the equilibrium concentration of the solute was analyzed gravimetrically. After a period of 25 days, optically good quality single crystals of dimension upto 18 x 5 x 4 mm3 are harvested. The photograph of as grown single crystals of LPM crystal is shown in Fig. 1.

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Fig. 1. Photograph of as grown LPM. RESULTS AND DISCUSSION Powder X-ray diffraction analysis. The LPM was subjected to powder X-ray diffraction analysis with a monochromatic Cu Kα radiation (λ = 1.5406 A°), recorded PXRD pattern of LPM is shown in Fig. 2. L-Phenylalanine maleic acid crystallizes in monoclinic structure with space group of P21.

Fig. 2. Experimental Powder XRD pattern of LPM. Computational Details. Quantum chemical Density functional theoretical (DFT) computations were performed using with the Gaussian program package using B3LYP functions combined with the 631 G(d, p) basis sets to derive the complete geometry optimizations and normal-mode analysis on isolated entities. Above said task was achieved using Gaussian03W program package, invoking gradient geometry optimization, implemented on Pentium core 2 duo/3 GHz processor with 2GB RAM personal computer [6]. Vibrational assignments. FT-IR spectrum of the grown crystal was recorded in the range 400 cm-1 to 4000 cm-1, using KBr pellet technique on BRUKKER IFS FT-IR Spectrometer. The experimental FT-IR spectrum was reported in the Fig. 3. The theoretically simulated FT-IR spectrum at B3LYP/631+G (d, p) basis set was shown in Fig. 4. It is found that LPM molecule has 24 moiety and is in stable conformation with C1 symmetry then exhibits 66 normal modes of vibrations. The O–H group gives rise to three vibrations (stretching, in-plane bending and out-of-plane bending vibrations). The O–H group vibrations are likely to be the most sensitive to the environment, so they show pronounced

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shifts in the spectra of the hydrogen bonded species. In the case of the un-substituted phenols it has been shown that the frequency of O–H stretching vibration in the gas phase is 3657 cm−1.

Fig. 3. Experimentally obtained FTIR spectrum of LPM.

Fig. 4. Theoretically obtained FTIR spectrum of LPM. Similarly, in our case a very strong FT-IR bands at 3905, 3743 and 3684cm−1are assigned to O–H stretching vibrations. The hydrogen bonding effect through hydroxyl group leads to dimer conformation OH stretching mode calculated at 3595cm−1 which is much closer to the FT-IR experimental observation at 3547cm−1. The O–H in-plane bending vibration in the phenols, in general lies in the region 1150–1250cm−1. The O–H out-of-plane bending mode for the free molecule lies below 300cm−1 and it is beyond the infrared spectral range of the present investigation. However, for the associated molecule the O–H out-of-plane bending mode lies in the region 517–710cm−1 inboth intermolecular and intra molecular associations, the frequency is at a higher value than in free O–H. The C-N ring stretching vibration bands occur in the region 1600 - 1500 cm−1. The present molecule exhibits this vibration in IR spectrum at1650cm−1and the theoretically computed value at 1650cm−1 by B3LYP method shows good agreement with recorded spectrum. C–N stretching absorption assigned in the region 1382–1266 cm−1. In the present work, the band observed at 1113 cm−1 in FTIR spectrum has been assigned to C–N stretching vibration. The calculated frequency at 1012 cm−1 is in good agreement with experimental value. The C-O stretching vibration for this LPM molecule is obtained at 1380 and 1230cm-1 in IR spectrum. Both the bands well coincided with theoretically calculated values at 1326 and 1223 cm-1 using B3LYP method. The band occurred at 216 cm-1is assigned to C-O out plane bending occurred. The lowering of C-O stretching mode is attributed to the fact that the C-O group chelate with the other nucleophilic groups, thereby forming both intra and intermolecular hydrogen bonding in the crystal. HOMO – LUMO Gap. In principle, there are several ways to calculate the excitation energies. The first, and the simplest one involves the difference between the highest occupied molecular orbital MMSE Journal. Open Access www.mmse.xyz

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(HOMO) and the lowest unoccupied molecular orbital (LUMO) of a neutral system. The indication of charge transfer from L-phenylalaninium to maleate moiety through the hydrogen bond, which is an important requirement to 0.05244 a.u. The calculated HOMO and LUMO energies clearly show that charge transfer occurs within the molecule. obtain large second order NLO response. The energies of the HOMO and LUMO, based on the optimized structure are computed as −0.10814 and −0.05570 a.u, respectively. The HOMO–LUMO energy gap is shown in Fig. 5. SHG efficiency. The nonlinear optical conversion efficiency has been carried out using the Kurtz and Perry technique. When the Q-switched Nd: YAG laser was passed through LPM specimen, second harmonic signal of 532 nm is generated it was confirmed by the emission of green light. The second harmonic signal of 190 mW was obtained for LPM single crystal with reference to KDP (130 mW). Thus, the SHG efficiency of LPM single crystal is nearly 1.5 times greater than KDP.

Fig. 5. HOMO –LUMO plot of LHDN at B3LYP/6-31 G (d, p). UV-Vis-NIR spectrum. The optical absorption spectrum of LPM single crystal is shown in Fig. 6. The spectrum indicates that LPM crystal has minimum absorption in the region between 200–1200 nm. The lower cut off wavelength was around 275 nm. The values of the direct optical band gap Eg were obtained from the intercept of (αhν) 2 versus hν curve. The optical band gap is found to be 4.5 eV which is useful for gas sensing applications.

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Fig.6. Optical absorption spectrum of LPM. Thermal Analysis. The TGA/DTA analysis of LPM crystal was carried out in the temperature range of 200-1000°C in the nitrogen atmosphere and is shown in Fig. 7. From the TGA curve, it is clear that the material is stable up to 130˚C before decomposition starts. In TGA, decomposition takes place after 151◦C as the first stage. It goes up to 240˚C which may be due to the loss of C 2H4 and 2CO2, resulting in a loss of weight of 18.36%. Another weight loss of 36.71% at the second stage, noticed between the temperatures: 250–350 ˚C is due to the expulsion of C6H5, CH2 and NH3. The next stage of decomposition results in a loss of 27.54% between the temperature range 340–500 ˚C is due to the release of CO2.The next stage of decomposition results in a loss of 27.54% between the temperature range 500–800 ◦C is due to the release of CO. The remaining residue corresponds to carbon of the LPM crystal. The sharp DTA peaks at 180 and 300 ˚C are attributed to the decomposition of the material, which match well with the first and second stage of decomposition in the TGA curve, respectively.

. Fig. 7. TG-DTA curves of LPM single crystals. Summary. L-Phenylalanine maleic acid single crystals were grown by slow evaporation technique at room temperature. Powder XRD confirmed the grown crystal. Theoretical and experimental MMSE Journal. Open Access www.mmse.xyz

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Spectroscopic studies exemplify the presence of various functional groups in the molecule. A frontier molecular orbital analysis gives the HOMO-LUMO energy gap value. The lower UV cut-off wavelength of the sample observed at 275 nm. The NLO efficiency was estimated. The promising crystal growth characteristics and properties of LPM crystal indicate it as a potential material for photonic, electro-optic and SHG device application. References [1] S. Natarajan, G. Shanmugam, S.A. Martin Britto Dhas, “Growth and characterization of a new semi organic NLO material L-tyrosine hydrochloride,” Cryst. Res. Technol, Vol. 43, pp. 561-564, 2008, DOI.10.1002/crat.200711048. [2] C. Ravikumar, I. Hubert Joe, D. Sajan, “Vibrational contributions to the second-order nonlinear optical properties of π-conjugated structure acetoacetanilide,” Chem. Phys, Vol. 369, pp. 1-7, 2010, DOI. 10.1016/j.chemphys.2010.01.022. [3] P. VinothKumar, R. Mohankumar, R. Jeyavel, A. Bhasharan, “Synthesis. Growth, structural, optical, thermal and mechanical properties of an organic Urea maleic acid single crystals for nonlinear optical applications,” Opt. Laser. Tech, Vol. 81, pp. 145-152, 2016, DOI. 10.1016/j.optlastec. 2016.02.004 [4] S. Tamilselvan, M. Vimalan, I. Vetha Potheher, S. Rajasekar, R. Jeyasekaran, M. Antony Arockiaraj, J. Madhavan, “Growth, thermal, dielectric and mechanical properties of Lphenylalanine–benzoic acid, A nonlinear optical single crystal,” Spectrochimica Acta Part A, Vol. 114, pp. 19-26, 2013, DOI. 10.1016/j.saa.2013.05.017 [5] M. Lydia Caroline, S. Vasudevan, “Growth and characterization of L-phenylalanine nitric acid, a new organic nonlinear optical material,” Mater. Lett, Vol. 63, pp. 41-44, 2009, DOI. 10.1016/j.matlet.2008.08.059. [6] J.B. Foresman, in: E. Frish (Ed), “Exploring chemistry with Electronic structure Methods: a Guide to using Gaussian, Gaussian Inc.,” Pittsburg, PA, 1996. Cite the paper K. Deepa, J. Madhavan, (2017). Synthesis, Vibrational Spectroscopy, Thermal Analysis, Non-Linear Optical Properties and DFT Calculation of a Novel L-Phenylalanine Maleic Acid Single Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.78.8.744

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Piezoelectric and Ferroelectric Properties of Lead-free 0.9(Na0.97K0.03NbO3)0.1BaTiO3 Solid Solution23 S. Sasikumar1, R. Saravanan1, S. Saravanakumar2 1 – Research Centre and Post Graduate Department of Physics, The Madura College, Madurai - 625 011, Tamil Nadu, India 2 – Department of Physics, Kalasalingam University, Krishnankoil, Viruthunagar - 626 126, Tamil Nadu, India DOI 10.2412/mmse.47.30.332 provided by Seo4U.link

Keywords: ceramics, piezoelectricity, X-ray diffraction, electronic structure.

ABSTRACT. Lead-free piezoelectric 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic has been synthesized using conventional solid-state reaction method. The results of X-ray diffraction analysis (XRD) show that the prepared sample displays typical perovskite structure with tetragonal space group P4mm. The crystal structure of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 powder was determined by Rietveld refinement analysis. The charge density distribution of the prepared sample has been investigated by using maximum entropy method. The optical band gap of the solid solution has been investigated using UV-visible spectroscopy (UV-Vis). Scanning electron microscopic (SEM) measurements were performed to study the surface morphology. The elemental composition of the 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 sample was analyzed by energydispersive X-ray (EDS) spectrometer. The ferroelectric nature of the sample has been determined through polarization and electric field hysteresis measurements.

Introduction. Lead-based piezoelectric materials like PZT (lead zirconate titanate) are the most widely used piezoelectric materials for its superior piezoelectric properties, but these Pb-based systems are highly toxic and volatile causing serious environmental hazards [1,2]. Recently, considerable research has been intensified on lead-free based piezoelectric materials [3]. In this context, (Na, K) NbO3 based ceramic systems are emerging as promising candidates for replacement of lead-based ceramics due to their excellent piezoelectric properties, high Curie temperature and environmental friendliness. Pure NKN ceramics are difficult to synthesize using the solid state reaction method due to the evaporation of K2O and Na2O at high temperatures and degradation of resistivity and the piezoelectric properties. It is also very difficult to control the evaporation of Na 2O and K2O by muffling. So, to synthesize the pure NKN samples and optimizations have been adapted by adjusting the Na/K ratio in A site of perovskite structure [4]. Several research works have been carried out by doping the extrinsic materials to increase the piezoelectric properties of NKN-based ceramic materials. Dopants such as LiTaO3 [5], CuO [6], ZnO, LiSbO3 [7], LiNbO3 [8], BaTiO3 [9], SrTiO3 [10], CaTiO3 [11], AgTaO3 [12], Fe2O3 [13], and Sb2O5 [14] have been added to NKN-based ceramics to form new NKN-based ceramic systems. In the present work, we report 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic was synthesized by solid-state reaction method. The ferroelectric and piezoelectric properties of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic were analyzed through charge density studies. Experimental. Solid solution sample of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 was prepared by conventional solid-state reaction method. Na2CO3 (99.99%), K2CO3 (99.99%), Nb2O5 (99.99%), BaCO3 (9.99%) and TiO2 (99.99%) were used as starting materials. The raw powders were weighed in the stoichiometric ratio of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 and mixed through ball milling using agate balls for 2 h. Then, the powder was calcined at 950 ºC for 4 h. The powder was then pressed © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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into discs (pellets) using a hydraulic press with 12 mm diameter and 1 mm thickness. These pellets were then finally sintered at 1250 °C for 2 h. The prepared solid solution was characterized using various techniques. The crystal structure and phase formation were confirmed by analyzing X-ray diffraction pattern of the sample obtained by X-ray diffractometer (Bruker AXS D8 Advance) in a wide range of angles (10° to 120°) with a scanning step size 0.02° at room temperature using CuKα radiation (λ = 1.54056 Å). Surface morphological and the compositional study was carried out using a scanning electron microscope (SEM) (JEOL JSM-6390LV) equipped with energy dispersive X-ray spectrometer (EDS) (JEOL JED-2300). Optical band gap analysis was carried out using Varian, Cary 5000 spectrophotometer in the wavelength range of 200-2000 nm. Piezoelectric constant (d33) of the sample was measured using a Piezo-d33 meter (SINOCERA, YE2730A d33 meter), after poling the pellet of the prepared ceramic sample in silicone oil at temperature 80 °C under 3-4 kV/mm for 30 min with no leakage current. P-E hysteresis loop was obtained by Radiant Precision Workstation ferroelectric testing system at room temperature. Results and discussion. Structural analysis Fig. 1(a) shows the powder X-ray diffraction pattern of the 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 solid solution. No peak corresponding to any secondary phase was observed in the X-ray diffraction pattern. It can be concluded that the Na0.97K0.03NbO3 and BaTiO3 ceramics form a homogeneous perovskite ABO3 structure. The crystal structure of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic possess tetragonal with P4mm symmetry. The inset of fig. 1(a) shows the splitting of the 46° diffraction peak (200) into (200) and (002) indicates tetragonal symmetry. In our work, the Rietveld refinement [15] was performed through the JANA 2006 program [16]. The fitted profile is shown in fig. 1(b). The lattice parameters and unit cell volume were calculated through of Rietveld refinement and are as presented in table 1. Table 1. Structural parameters. Parameters

Values

a=b (Å)

3.9471(8)

c (Å)

3.9283(7)

Space group

P4mm

Volume (Å3)

61.30(2)

Density (gm/cc)

4.45(1)

RP (%)

6.30

Robs (%)

2.13

*F(000)

*Number of electrons in the unit cell

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Fig. 1. a) X-ray diffraction pattern of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3.

Fig. 1. b) Fitted powder XRD profile.

Microstructural properties. To study the influence of BaTiO3 content on the microstructure of Na0.97K0.03NbO3 ceramics, their surface morphology was characterized by the scanning electron microscopy. Fig. 2 shows the corresponding SEM pattern of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 sample. It can be seen that the SEM particles are finely distributed without much agglomeration. Fig. 3 show the EDS spectra for the prepared samples. The result indicates that the constituent ions are present in the respective samples in expected proportion. No additional impurities are detected in the EDS spectrum. The numerical values of the percentages of atom and weight are given in table 2. It is interesting to note that the preparation condition completely favors the formation of mixed BaTiO3 and allow us to study the effect of the properties of the Na0.97K0.03NbO3.

Fig. 2. SEM image.

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Fig. 3. EDS spectra.

Fig. 4. UV-Visible plot. Table 2. EDS elemental composition for 0.9(Na0.97K0.03NbO3)-0.1BaTiO3. Weight (Wt %)

Atomic (At %)

13.06

0.77

47.79

9.37

1.51

28.51

18.87

1.36

17.41

2.31

1.07

60.33

Optical properties. The band gap energy of the prepared sample 0.9(Na0.97K0.03NbO3)-0.1BaTiO3, ceramic was evaluated using UV-visible spectra. Optical band gap was determined using the equation proposed by Wood and Tauc [17], αhν=A(hν-Eg)n where A is a constant, α is the absorbance, hν is photon energy, Eg is energy band gap, n=1/2 for direct band gap materials and n=2 for indirect band gap materials. Using Tauc’s relation, a graph is drawn with the energy value in X-axis and (αhν)2 in Y-axis. By extrapolating the linear portion of the curve as shown in fig. 4, the band gap values are estimated to be 3.40 eV.

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Fig.5. Ferroelectric P-E hysteresis loops of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramics at room temperature Ferroelectric and piezoelectric properties. The ferroelectric properties of the 0.9(Na0.97K0.03NbO3)0.1BaTiO3 ceramic was investigated in terms of their P-E hysteresis loop at room temperature as shown in fig. 5. The maximum polarization (Pmax), remnant polarization (Pr) and coercive field (Ec) values observed for the sample are 23.83 µC/cm2, 20.12 µC/cm2, 1.3 kV/mm, respectively. The piezoelectric coefficient (d33) of polarized 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic proves strong piezoelectric responses of the prepared ceramics. The polarized ceramic 0.9(Na0.97K0.03NbO3)0.1BaTiO3 have piezoelectric d33 value of 110 pC/N. This implies an essential relation between the piezoelectric property and the ferroelectric nature of the 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic. Charge density analysis from maximum entropy method. Maximum entropy method (MEM) [18] is an important and accurate technique to deal the electron density distribution in the unit cell because of their probabilistic approach. Also, it only needs a minimum amount of information from the observed XRD spectra and it yields least biased information. This method is packaged by the software PRactice Iterative MEM Analyses (PRIMA) [19]. The structure factors extracted from Rietveld refinement technique [15] were used for this study. The electron density distribution in the unit cell was constructed through the PRIMA [19] software. The MEM calculation for 0.9(Na0.97K0.03NbO3)0.1BaTiO3 ceramic was carried out using 64×64×64 pixels along a, b and c axes of the tetragonal lattice. The results are visualized using visualization software VESTA (Visualization for Electronic and Structural Analysis) [19]. Three-dimensional charge density distributions in the unit cell of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 is constructed with similar iso-surface levels of 1 e/Å3 and are presented in fig. 6 (a) and (c) with (001) and (002) planes shaded which gives a better view of how the charges are spatially distributed between constituent atoms inside the unit cell. Fig. 6 (b) and (d) shows that the two-dimensional charge density distributions on (001) and (002) planes with the enlarged view of electron density distribution around Na, Nb and O atoms. It is evident that the contour lines are faded away from the boundary of the Na and O atoms (fig. 6(b)) which reveal that there is no charge accumulation at the middle of the bond. This qualitatively confirms that between the Na and O atoms, the bond is ionic in nature. But, as far as the two-dimensional electron density map for the Nb-O bond in the (002) plane is concerned, it is clear from the fig. 6(d) that there is an increase of charges in the bonding region between the two atoms which authenticate that Nb-O bond is covalent in nature. These results are quantitatively analyzed by plotting one-dimensional charge density profile along Na-O and Nb-O, which are shown in fig. 7 (a) and (b). The mid bond electron density values are tabulated in table 3. We have attempted to correlate the piezoelectric response of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 with charge density distributions in the host lattice. Then Nb-O bond is facilitating the vibrations in the NbO6 octahedrons. The mid bond electron density value between Nb and O atoms is 1.0445 e/Å3 (table 3). The higher value of mid-bond electron density confirms covalent character between Nb and O atoms. The presence of more charges in the mid-bond region MMSE Journal. Open Access www.mmse.xyz

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of Nb-O atoms may be attributed to the enhanced ferroelectric and piezoelectric properties. The maximum polarization and d33 values for prepared sample are 23.83 µC cm-2 and 110 pC N-1. XRD results show that the prepared sample possesses tetragonal structure that might be due to the increase of off-centered octahedral Nb ion displacement. This may lead to enhanced ferroelectric and piezoelectric properties of the composition.

(a)

(d)

(c)

(b)

Fig. 6. a) 3D unit cells of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 with a) (001) and c) (002) planes shaded. Two dimensional electron density distribution on b) (001) and d) (002) planes for 0.9(Na0.97K0.03NbO3)-0.1BaTiO3.

(a)

(b)

Fig. 7. One dimensional electron density profiles along a) Na and O b) Nb and O atoms. Table 3. Bond lengths and mid bond electron densities for Na-O, Nb-O bonds.

Bonding Na-O

Nb-O

Bond length (Å)

Mid bond electron density (e/Å3)

Bond length (Å)

Mid bond electron density (e/Å3)

2.7901

0.0695

1.9741

1.0445

Summary. 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 ceramic has been prepared by solid state reaction method. The phase and structural properties have been analyzed by X-ray diffraction in the Na0.97K0.03NbO3 ceramic by doping BaTiO3. Piezoelectric, ferroelectric and charge derived properties of the grown sample have been correlated. The covalent nature between Nb and O ions was revealed from charge density studies, which are responsible for the piezoelectric properties of 0.9(Na0.97K0.03NbO3)-0.1BaTiO3. The band gap for the prepared sample was estimated by UV-visible spectra and it found to be 3.40 eV. The morphological study was performed by scanning electron microscopy. The elemental composition of the grown sample was also analyzed by using EDS spectrum. References MMSE Journal. Open Access www.mmse.xyz

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[1] Y. Saito, H. Takao, T. Tani, T.T. Nonoyama, K. Takatori, T. Homma, T. Nagaya and M. Nakamura, (2004) Lead-free piezoceramics. Nature 432, 84. DOI:10.1038/nature03028 [2] T.R. Shrout and S.J. Zhang, (2007) Lead-free piezoelectric ceramics: Alternatives for PZT? J Electroceram. 19, 113. DOI: 10.1007/s10832-007-9047-0 [3] W. Liu, X. Ren, (2009) Large piezoelectric effect in Pb-free ceramics, Large Piezoelectric Effect in Pb-Free Ceramics Phys. Rev. Lett. 103. 257602. DOI:doi.org/10.1103/PhysRevLett.103.257602 [4] Q. Zhang, B. Zhang, H. Li, P. Shang, (2010) Effects of Na/K ratio on the phase structure and electrical properties of NaxK1-xNbO3 lead-free piezoelectric ceramics, Rare Metals. 29, 220-225. DOI: 10.1007/s12598-010-0038-y [5] M.R. Yang, C.-S. Hong, C.C. Tsai, S.Y. Chu, (2009) Effect of sintering temperature on the piezoelectric and ferroelectric characteristics of CuO doped 0.95(Na0.5K0.5)NbO3-0.05LiTaO3 ceramics, J. Alloys Compd. 488, 169-173. DOI:10.1016/j.jallcom.2009.07.174 [6] H.Y. Park, I.T. Seo, J.H. Choi, S. Nahm, H.G. Lee, (2010) Low-temperature sintering and piezoelectric properties of (Na0.5K0.5)NbO3 lead-free piezoelectric ceramics, J. Am. Ceram. Soc. 93, 36-39. DOI: 10.1111/j.1551-2916.2009.03359.x [7] G.Z. Zang, J.F. Wang, H.C. Chen, W.B. Su, C.M. Wang, P. Qi, B.Q. Ming, J. Du, L.M. Zheng, S. Zhang, T.R. Shrout, (2006) Perovskite (Na0.5K0.5 )1-x(LiSb)xNb1-xO3 lead-free piezoceramics, Appl. phys. Lett. 88, 212908. DOI: 10.1063/1.2206554 [8] J. Zeng, Y. Zhang, L. Zheng, G. Li, Q. Yin, (2009) Enhanced ferroelectric properties of potassium sodium niobate ceramics modified by small amount of K3Li2Nb5O15, J. Am. Ceram. Soc. 92, 752754. DOI: 10.1111/j.1551-2916.2008.02921.x [9] D. Lin, K.W. Kwok, H.L.W. Chan, (2007) Structure, dielectric, and piezoelectric properties of CuO-doped K0.5Na0.5NbO3-BaTiO3 lead-free ceramics, J. Appl. Phys. 102, 074113. DOI: 10.1063/1.2787164 [10] R.C. Chang, S.Y. Chu, Y.P. Wong, Y.F. Lin, C.S. Hong, (2007) Properties of (Na 0.5 K0.5)NbO3SrTiO3 based lead-free ceramics and surface acoustic wave devices, Sens. Actuators A: Phys. 136, 267–272. DOI:10.1016/j.sna.2006.11.002 [11] R.C. Chang, S.Y. Chu, Y.F. Lin, C.S. Hong, Y.P. Wong, (2007) An investigation of (Na0.5K0.5)NbO3-CaTiO3 based lead-free ceramics and surface acoustic wave devices, J. Eur. Ceram. Soc. 27, 4453-4460. DOI:10.1016/j.sna.2006.11.002 [12] Y. Wang, L. Qibin, F. Zhao, (2010) Phase transition behavior and electrical properties of [(K0.50Na0.50)1-xAgx](Nb1-xTax)O3 lead-free ceramics, J. Alloys Compd. 489, 175-178. DOI:10.1016/j.jallcom.2009.09.047 [13] R. Zuo, Z. Xu, L. Li, (2008) Dielectric and piezoelectric properties of Fe 2O3-doped (Na0.5K0.5)0.96Li0.04Nb0.86Ta0.1Sb0.04O3 lead-free ceramics, J. Phys. Chem. Solids 69, 1728-1732. DOI:10.1016/j.jpcs.2008.01.003 [14] Q. Zhang, B.-P. Zhang, H.-T. Li, P.-P. Shang, (2010) Effects of Sb content on electrical properties of lead-free piezoelectric [(Na0.535K0.480)0.942-Li0.058] (Nb1-xSbx)O3 ceramics, J. Alloys Compd. 490, 260-263. DOI:10.1016/j.jallcom.2009.09.172 [15] H.M. Rietveld, (1969) A Profile Refinement Method for Nuclear and Magnetic, J. Appl. Cryst. 2, 65-71. doi.org/10.1107/S0021889869006558 [16] V. Petříček, M. Dušek, L. Palatinus, Jana 2006. The Crystallographic Computing System, Institute of Physics, Prague, Czech Republic, 2006. [17] D.L. Wood, J. Tauc, (1972) Weak absorption tails in amorphous semiconductors. Phys. Rev. B5, 3144. MMSE Journal. Open Access www.mmse.xyz

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[18] D.M. Collins, (1982) Electron density images from imperfect data by iterative entropy maximization, Nature 298, 49-51. [19] K. Momma, F. Izumi, Commission on Crystallogr. Comput., IUCr Newslett., No.7, 106 (2006). Cite the paper S. Sasikumar, R. Saravanan, S. Saravanakumar, (2017). Piezoelectric and Ferroelectric Properties of Leadfree 0.9(Na0.97K0.03NbO3)-0.1BaTiO3 Solid Solution. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.47.30.332

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Synthesis and Physicochemical Investigation of THz Material: 4â&#x20AC;&#x201C;Ethoxy Benzaldehydeâ&#x20AC;&#x201C;4'â&#x20AC;&#x201C;N'â&#x20AC;&#x201C;Methyl Stilbazolium Hexafluorophosphate (EMBSHP) 24 A. Karolin Martina1, J. Arul Martin Mani1, N.S. Nirmala Jothi1, P. Sagayaraj1 1 â&#x20AC;&#x201C; Department of Physics, Loyola College, Nungambakkam, Chennai â&#x20AC;&#x201C; 600 034, India a â&#x20AC;&#x201C; jmjnirmala@yahoo.co.in DOI 10.2412/mmse.62.28.0 provided by Seo4U.link

Keywords: organic compound, crystal growth, nonlinear optical, thermal behaviour.

ABSTRACT. Single crystals of organic optic material 4â&#x20AC;&#x201C;Ethoxy Benzaldehydeâ&#x20AC;&#x201C;4'â&#x20AC;&#x201C;N'â&#x20AC;&#x201C;Methyl Stilbazolium Hexafluorophosphate (EMBSHP) were grown by slow evaporation technique at room temperature using acetone â&#x20AC;&#x201C; water (3:1) mixed solvent. The grown crystal was subjected to single crystal X â&#x20AC;&#x201C; ray diffraction analysis to identify the crystal structure and lattice parameter. The crystal belongs to the triclinic crystal system. The composition of the crystal was studied by CHN analysis. The presence of functional groups of the title crystal were confirmed from the FTIR spectral studies. The optical transmission range of the grown crystal was measured by UV â&#x20AC;&#x201C; Vis â&#x20AC;&#x201C; NIR spectral studies. The melting point of the grown crystal was found from DSC analysis.

Introduction. Organic NLO materials with excellent optical characteristics such as high sensitivity and short response time have attracted much attention due to their potential applications in optical switching, optical processing, optical computing, optical data storage and terahertz (THZ) technology. Among the numerous organic materials, the well-known and most investigated organic NLO crystal is the stilbazolium salt trans-4-N-(dimethylamino)-N-Methyl-4-stilbazolium tosylate (DAST). It has very high electro optical (EO) and NLO figures of merit. Among all the other organic THz material, DAST has the largest NLO coefficient, d 11 of 540 Âą 110 pm/V at đ??&#x20AC;~1540 nm, EO figure of merit r11=47 Âą 8 pm/V at đ??&#x20AC;~1535 nm and lower dielectric constant making it suitable for optoelectronic applications [1,2]. The advancement in the field of photonics have increased the demand for new nonlinear optical (NLO) materials. Especially, molecules exhibiting strong two photon absorption (TPA) are of practical importance in photons applications such as frequency up conversion lasing, three dimensional fluorescence imaging and multi photon microscopy ,eye and sensor protection, optical signal reshaping and stabilizing fast fluctuations of laser power. To expand these utilizing, designing the molecule with large TPA cross section plays a vital role [3]. DAST crystal can generate short THz pulse by optical rectification with a sub-picosecond laser [4, 5], or widely tunable THz waves by different frequency generation (DFG) with a dual wavelength nanosecond laser [6]. In this present study, the tosylate anion of DAST is replaced by Hexafluorophosphate (PF-6) and two methyl group along with nitrogen in the cation is replaced by ethoxy group for achieving the stilbazolium crystal 4-Ethoxy benzaldehyde 4' - N' -methyl stilbazolium Hexafluorophosphate (EMBSHP). The grown crystal has been subjected to single crystal XRD, CHN, FTIR, Optical absorption and thermal analysis. Synthesis. EMBSHP was synthesized by metathesization of the 4 - ethoxybenzaldehyde â&#x20AC;&#x201C; N â&#x20AC;&#x201C;methyl â&#x20AC;&#x201C; 4 - stilbazolium iodide (EMSI) salt with sodium hexafluorophosphate. EMSI was synthesized by the condensation of 1,4- dimethyl pyridinium iodide (2.35g, 10 mmol), methanol (30 ml) and 4ethoxy benzaldehyde (1.36g, 10 mmol) in the presence of piperidine (0.2 ml). The total mixture was ÂŠ 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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taken in a round-bottom flask (1000 ml capacity) of a Dean-Stark apparatus and refluxed for 15 hours, then cooled to room temperature. The product was filtered and recrystallized from methanol four times for purification. During the next stage, the metathesization reaction was carried out with aqueous sodium hexafluorophosphate. A yellowish precipitate was formed as a result of exchange reaction between anion and cation. The remaining aqueous sodium iodide solution was removed from the precipitation. The purity of EMBSHP was further improved by successive recrystallization from acetone. Crystal growth. After testing several common solvents and their combinations, it was found that the solubility of EMBSHP can be improved by using acetone. The size of the grown crystals were small when acetone was used as solvent. The size of the grown crystals improved a lot when the mixed solvent of water and acetone was used as solvent. We compared solvent mixtures of acetone and water with 5:1, 4:1, 3:1, 2:1 and 1:1 proportion and found that EMBSHP dissolved best and the size of the crystals were bigger for the 3:1 ratio. 100 ml of the above mentioned solvent was taken in a beaker and 1.7 g of EMBSHP was added slowly and stirred continuously for three days to prepare a saturated solution at room temperature. The saturated solution was filtered, sealed with perforations and was set aside to undergo slow evaporation. After two weeks, crystals of size up to 7 mm x 1 mm x 1 mm were obtained. The photograph of as-grown crystal is shown in Fig. 1.

Fig. 1. Photograph of EMBSHP crystals. Results and discussion Single crystal XRD. Single crystal X-ray diffraction was analyzed using ENRAF NONIUS CAD-4 diffractometer. It is found that the grown EMBSHP Single crystal belongs to the triclinic system, and the observed lattice parameters are a = 6.38 Å, b = 9.51 Å, c = 14.33 Å, α = 90.14 ⁰, β = 93.89 ⁰, γ = 90.32⁰and volume V= 867 Å3. CHN analysis. The elemental composition of slow evaporation method grown EMBSHP crystal was carried out by CHN analysis. The calculated value of C16H19N1O1P1F6 are C = 49.76% H = 4.91% and N = 3.6% the corresponding experimentally found values are: C = 49.36% H = 5.05% N = 3.8%. Thus there is a close argeement between the calculated and experimental values of CHN. FT-IR analysis. The sample was characterized by FT-IR spectroscopy in order to identify the functional groups and detect the vibrational modes of the molecules of the sample. The FTIR spectrum was recorded using BRUKER IFS 66V FT-IR spectrometer. The vibration frequencies observed between 500 cm-1 and 700 cm-1 are due to the out of plane bending of the ring C-H bonds. The frequencies observed between 1100 cm-1 and 1200 cm-1are corresponding to the plane ring confirmation modes [1]. The measurement was done with KBr method for the wavelength range 400MMSE Journal. Open Access www.mmse.xyz

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4000 cm-1 and the spectrum is shown in fig.2 The characteristic frequencies observed between 3347 cm-1due to the N-H stretching vibration of primary amine of 4-aminopyridine. The peak at 2903 cm- 1 is assigned to the alkyl C-H stretch. The peak at 1588 and 1525cm-1 Attributed to the aromatic vibrations observed.1183 cm-1 are pertaining to the S=O stretch modes of sulfonate group and further peak 1043 cm-1 confirm the presence of νC-O-C linkage. The peak at 844 cm-1 is assigned for 1, 4 distribution aromatic vibration [7].

Fig. 2. FTIR Spectrum of EMBSHP crystal. Optical transmittance studies The optical transmittance range and the transparency cut off wavelength of single crystal are most significant optical parameters for laser frequency applications. The optical absorption spectrum of EMBSHP crystal in solution form was recorded in the wavelength range of 200 - 1100 nm using Varian Cary 5E UV-VIS-NIR spectrometer using acetone and water as solvent. Absorbance is not found in the wavelength region of 445 – 1100 nm and it shows an excellent optical behavior of the crystal. It is also reported that absence of absorption in the region between 445 and 1100 nm showed that EMBSHP crystal could be explotied for second and third order nonlinear optical applications using Nd:YAG laser [8].

Fig. 3. Optical Absorbtion Spectrum of EMBSHP crystal. MMSE Journal. Open Access www.mmse.xyz

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Thermal Analysis The DSC thermal analysis was carried out in nitrogen atmosphere at a heating rate of 10℃/minute from room temperature up to 500 ⁰C. The endothermic peak at 275.2 ⁰C in the DSC trace (Fig.4) corresponds to melting point of the material and the exothermic peak corresponds to the major decomposition of the material starting from the removal of stilbazolium ion followed by the hexafluorophosphate anion.

Fig. 4. DSC trace of EMBSHP crystal. Summary. The growth of single crystal of EMBSHP was achieved by slow evaporation method. From Single crystal XRD analysis the crystal system is found to triclinic. The composition of the sample was verified by CHN and FT-IR studies. The UV – vis – NIR studies show that the crystal is transparent in the wave length range 445 – 1100 nm. From the DSC curve, the melting point of the crystal is found to be 275.2 ⁰C which is higher than the melting point of the well known oraganic THz crystal DAST(256⁰C). The material is found to be thermaly stable and decomposes above the melting point. References [1] Pan. F, Knopfle. G, Bosshard. Ch, Follonier. F, Spreiter. R, Wong. M.S, Gunter. P, Appl. Phys. Lett. 69 (1996) 13. doi.org/10.1063/1.118101 [2] R. JeraldVijay, N. Melikechi, T. RajeshKumar, Joe G.M. Jesudurai, P. Sagayaraj, Journal of Crystal Growth 312 (2010) 420.doi.org/ 10.1016/j.jcrysgro.2009.10.067 [3] X.-C. Zhang, X.F. Ma, Y. Jin, T.-M. Lu, E.P. Boden, P.D. Phelps, K.R. Stewart, C.P. Yakymyshyn, Appl. Phys. Lett. 61, (1992) 3080. doi.org/10.1063/1.107968 [4] A. Schneider, I. Biaggio, P. doi.org/10.1016/j.optcom.2003.07.013

Gu¨

nter,

Opt.

Commun.

224

(2003)

337.

[5] K. Kawase, M. Mizuno, S. Sohma, H. Takahashi, T. Taniuchi, Y.Urata, S. Wada, H. Tashiro, H. Ito, Opt. Lett. 24 (1999) 1065.doi,org/10.1364/OL.24.001065 [6] P.Poornesh, S.Shettigar, G.Umesh, K.B.Manjunath, K.Prakash Kamath, B.K.Sarojini, B.Narayana, Opt.Mater, 31(2009) 854-859. doi.org/10.1016/j.optmat.2008.09.007

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[7] C.H.Choi, M.Kertesz, Journal of Physical Chemistry A 101(1997) 3823.doi,org/10.1021 / jp97062ov [8] N.Ashour,S.A.EI-Kadry,Mahmoud, on the elecrtical and optical properties of Cds films thermally deposited by a modified source,Thin solid films 269 (1995)117-120. Doi org/10.1016/00406090(95)06868-6. Cite the paper A. Karolin Martina, J. Arul Martin Mani, N.S. Nirmala Jothi, P. Sagayaraj, (2017). Synthesis and Physicochemical Investigation of THz Material: 4–Ethoxy Benzaldehyde–4'–N'–Methyl Stilbazolium Hexafluorophosphate (EMBSHP). Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.62.28.0

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Recycling Technology of Fiber-Reinforced Plastics Using Sodium Hydroxide 25 K. Baba1, a, T. Wajima1 1 – Department of Urban Environment System, Chiba University, 1-33,Yayoi-cho, Chiba 263-8522, Japan a – afsa3284@chiba-u.ac.jp DOI 10.2412/mmse.8.14.523 provided by Seo4U.link

Keywords: fiber-reinforced plastics, sodium hydroxide, pyrolysis, silica extraction.

ABSTRACT. Glass fiber-reinforced plastics (GFRP) are high strength materials by reinforcing resin with glass fiber, and are increasing annually because FRP is a light weight with high corrosion resistance. However, disposal treatment of it is difficult due to its high stability, and cause illegal waste dumping of big GFRP products, such as ship, bath, tank and so on. In this study, we attempted to convert plastic and glass fiber in the FRP into gas, oil and water glass using sodium hydroxide reaction, respectively. GFRP was cut into the peace with the diameter of 1 cm. Sample peaces (4g) and sodium hydroxide (2g - 12g) put into the reactor, and the reactor was heated with an electric furnace while flowing nitrogen (160 mL/min). After heating to setting temperature (300 - 450 ºC) for 1 h, the reactor was naturally cooled to room temperature. The generated gas and oil during the reaction was collected by gas pack and oil trap, respectively. After cooling, the residue inside the reactor was washed with distilled water, and filtrates to obtain the residual substance, and silicon concentration in the filtrate was measured to calculate the silicon extracted content from GFRP. By using pyrolysis with sodium hydroxide, GFRP can be decomposed by correcting the resin into the gases, such as hydrogen and methane, and glass fiber into soluble salt in order to be extracted into the solution. GFRP can be decomposed by pyrolysis with NaOH above 400oC.

Introduction. Glass fiber-reinforced plastic (GFRP) is light weight, high strength and high durability, and is widely used worldwide for bath tubs, automobile parts, railway car parts, small ships, etc [1]. In Japan, GFRP has been used since 1955 and its production has gradually declined after reaching 480,000 ton in 1996. On the other hands, the amount of discarded FRP is increasing year by year. Most of waste GFRP is disposed of by incineration or landfill, and 2% of waste GFRP is recycled as cement raw fuel or concrete additive [2, 3]. GFRP is molded by combining an organic matter of a thermosetting resin, such as an unsaturated polyester resin, and an inorganic material of glass fibers. It is difficult to recycle FRP. Because the resin does not reform is not soluble in any solvents, the amount of heat generated by GFRP is too small to use as fuel due to the glass fiber contents. Therefore, in Japan, the development of resource recycling technology of GFRP is promoted by enactment of law on recycling. As a current GFRP recycling method, a chemical recycling method of decomposition using a solvent [4] or subcritical water [5] has been studied. However, these chemical recycling methods for waste GFRP are the high cost by high temperature and high pressure, so it has not yet been put into practical use. In this study, we attempted to develop a new recycling technology for thermal decomposition method using sodium hydroxide for recovering gas, oil and glass from waste GFRP at normal pressure and low temperature. Material and Methods. The sample used in this study is waste GFRP obtained from one of the intermediate treatment contractors in Japan. GFRP was cut for use as a sample (size: 1.0 × 1.0 × 0.05 cm) as shown in Fig. 1.

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The experimental apparatus is shown in Fig.2. GFRP(4g) and NaOH(2 â&#x20AC;&#x201C; 12g ) put into the reactor, and heated to setting temperatures with an electric furnace while flowing nitrogen (160 mL/min). After heating to setting temperature, the reactor was heated for 1-h, and then naturally cooled to room temperature. Since the residual substance was included in fused salt solid, it dissolves in distilled water, and filtrates to obtain the residual substance in the reactor. After filtering, the residue remaining on the filter paper was observed, and th weight of the residual was measred to calculate residual weight ratio. The amount of silicon extracted into the filtrate was analyzed by an atomic absorption spectrophotometers (AAnalyst200, Perkin-Elmer). During the experiment, the gas generated in the reactor pass through the water bubbling bottle to capture the halogen content in the gas, then the passing gas was collected in gas pack. The collected gas was analyzed by a gas chromatograph (GC2014ATF, SHIMADZU).

Fig. 1. Photo of GFRP samples(left) and GFRP after cutting (right).

Fig. 2. Experiment apparatus. Result and discussion. Figure 3 shows the photos of the residues with various NaOH addition.The reaction time is 1-h and the reaction temperature is 400 oC. Without addition of NaOH, GFRP could not be decomposed and remained piece with glass fiber can be of obserbed (Fig.3(a)). With addition of NaOH(Fig.3(b)~(d)), the resin and the glass fiber were not observed due to the decomposition of resin and glass fiber by pyrolysis with NaOH.

Fig. 3. The residue after the pyrolysis with addition of NaOH of (a) 0 g, (b) 4 g, (c) 8 g and (d) 12 g. MMSE Journal. Open Access www.mmse.xyz

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Figure 4 shows the residual weight ratio of the residue after pyrolysis with without NaOH addition. While 90% weight of raw sample was remained by pyrolysis without NaOH, the residue weight decreases by pyrolysis with sodium hydroxide.

Fig. 4. Residual weight ratio of the residual after pyrolysis with different NaOH addition. Figure 5 shows the product gas during the experiment (Fig. 3(a) ~ (d)). Production of gas without NaOH is lower than those with NaOH. Production of hydrogen gas and methane gas was confirmed, and the production of hydrogen and methane gas increased.with increasing sodium hydroxide addition.

Fig. 5. The product gas from GFRP using pyrolysis with sodium hydroxid. Figure 6 shows Si content extracted from the residue of the pyrolysis. While Si content could not be extracted from the residual of the pyrolysis without NaOH. Si content could be extracted from the residue of the pyrolysis with sodium hydroxide. With increasing NaOH addition, a larger amount of Si can extracted into the solution. The weight of GFRP was reduced by decomposing the resin into gas and extracting the glass fiber into the filtrate by pyrolysis with NaOH. Figure 7 shows the photos of the residue of the pyrolysis with NaOH at various temperatures. The reaction time is 1-h and NaOH addition is 1 g/g. At 300oC, the form of GFRP remained, and decomposition of the resin and the glass fiber could not be observed MMSE Journal. Open Access www.mmse.xyz

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(Fig. 7(e)). At 350oC, decomposition of the resin could be observed, and decomposition of the glass fiber could not be observed (Fig. 7(f)). At 400 and 500oC, decomposition of both resin and glass fiber was observed (Fig. 7(h)).

Fig. 6. Si content extracted from residue after the experiment.

Fig. 7. The residue after the experiment at (a) 300oC, (b) 350oC, (c) 400oC and (d) 500oC. Figure 8 shows the residual weight ratio of the pyrolysis at various temperatures. With addition of sodium hydroxide with increasing the reaction temperature, the residual weight decrease.

Fig. 8. Residual weight ratio of the residue of the pyrolysis at different reaction temperatures.

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Figure 9 shows the product gas by pyrolysis at various temperature, with NaOH addition, Regardless of reaction temperatures production of hydrogen gas and methane gas was confirmed by pyrolysis with sodium hydroxide. A larger amount of methane and hydrogen gases can be generated, with increasing the reaction temperature.

Fig. 9. Product gas from the GFRP using pyrolysis with sodium hydroxide at different temperature. Figure 8 shows Si content extracted from the residue of the pyrolysis at various temperature. Si can be extracted from the residue of the pyrolysis with NaOH above 400 oC, while at 300oC and 350oC, extracted Si content was not confirmed.

Fig. 10. Si content extracted from the residue of the pyrolysis with NaOH at various temperatures. From these results, GFRP can be decomposed by the pyrolysis with NaOH above 400 oC. Summary. In this study, we attempted to decompose GFRP using pyrolysis with sodium hydroxide. By using pyrolysis with sodium hydroxide, GFRP can be decomposed by correcting the resin into the gases, such as hydrogen and methane, and glass fiber into soluble salt in order to be extract into the solution. References MMSE Journal. Open Access www.mmse.xyz

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[1] K. Shibata, FRP Recycling Technology, NetworkPolymer, Vol.28 (4), 2007, 43-48. DOI: 10.11364/networkpolymer1996.28.247 [2] A. Kondo, Development of Light Weight Materials with Low Thermal Conductivity by Making Use of Waste FRP, J. Soc. Powder Technol, Vol.47, 2010, 768-772 DOI: 10.4164/sptj.47.768 [3] F.Yoshimichi, I : The Present Conditions of GFRP which Aimed at the Environmental Load Reduction, The Society of Materials Science, Vol.57(6), 2008, 621-625, DOI: 10.2472/jsms.57.621 [4] T. Iwata, Recycling of fiber Reinforced Plastics Using Depoly-merization by Solvothermal Reaction with Catalyst, Journal of Materials Science, Vol.43, 2008, 2452-2456, DOI: 10.1007/s10853-007-2017-8 [5] T. Nakagawa, FRP Recycling Technology Using Subcritical Water Hydrolysis, NetworkPolymer, Vol.27, 2006, 88-95, DOI: http://doi.org/10.11364/networkpolymer1996.27.88 Cite the paper K. Baba, T. Wajima, (2017). Recycling Technology of Fiber-Reinforced Plastics Using Sodium Hydroxide. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.8.14.523

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Synthesis, Growth and Optical, Electrical, Thermal Properties of L- Proline Adipate Single Crystals for Nonlinear Optical Applications 26 N. Indumathi1, K. Deepa2, J. Madhavan2, S. Senthil1, a 1 – Department of physics, Government Arts College, Nandanam, Chennai-600035. 2 – Department of physics, Loyola College, Chennai-600034, India.

a – indumathy.phy@gmail.com DOI 10.2412/mmse.5.76.497 provided by Seo4U.link

Keywords: solution growth, single crystal XRD, UV-Vis-NIR, dielectric studies, TG/DTA and SHG.

ABSTRACT. Optically good quality L-Proline Adipate (LPA) crystals have been grown by slow evaporation method. The cell parameters of the grown crystal were determined by single crystal X-ray diffraction technique. The band gap energies of the LPA single crystals have been calculated and their cut off frequencies was determined from UV-vis NIR spectral analysis. The dielectric behaviour of grown crystals has been studied in the frequency range from 50Hz to 5MHz. The thermal behaviours were identified by TG/DTA analyzes. The second harmonic generation (SHG) efficiency was studied by using Kurtz powder technique.

Introduction. A major effort was developed to use the nonlinear optical (NLO) materials to generate different frequencies that are not available and also to develop the potential of tunable laser beams [1]. Many researchers have been focussed on the materials, which produce second harmonic generation, telecommunication, optical computing, optical data storage and optical information processing [2]. Amino acids with organic salts are prominent promising materials for the application of NLO devices [3]. These complexes are better alternative for KDP crystals in all respects. Growing single crystals with necessary properties is important in the field of laser technology. Hence great attention has been given to grow and characterize single crystals to modify their properties for the device fabrications [4]. L Proline is one of the two amino acids it contains α-amino, which is in the protonated NH2+ group and also contain α-carboxylic acid, which is in the deprotonated COO− group which create hydrogen bonds [5]. In the present work, we report the growth of L-Proline Adipate single crystals by slow evaporation technique. The grown LPA crystals were characterized by Single crystal XRD, UV-Vis-NIR spectroscopy, Dielectric Studies, Thermal studies and NLO studies. Experimental Procedure. The commercially available L-Proline and Adipic acid salts were used to prepare the LPA single crystals by slow evaporation solution growth method at ambient temperature. The solution was prepared using deionised water as the solvent. The saturated solutions of L-Proline Adipate (LPA) were prepared separately and then the filtered solutions were taken in the ratio of 1:2. The mixed solution was stirred continuously using magnetic stirrer for 4 hours and kept in a dust free environment for evaporation. After 50 days, transparent LPA crystal of measuring 12x5x4 mm3 was harvested. The photograph of as grown single crystal of LPA is shown in Fig. 1.

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Fig. 1. Photograph of LPA Single crystal. Results and Discussion Single crystal X-ray diffraction analysis. The single-crystal XRD of LPA crystals were carried using ENRAF NONIUS CAD4 X-ray diffractometer. The cell parameters of LPA single crystal are a = 9.875(2) Å, b = 8.155(4) Å, c = 10.006(13) Å, α = γ = 90 ◦, β = 110.038◦, and volume = 856.1(3) Å3. The analysis of XRD data revealed that the grown crystals have been crystallised at monoclinic symmetry. UV – Vis – NIR studies. The grown crystal has been characterized by UV-vis-NIR studies using Shimadzu UV 2450 spectrophotometer. The recorded Absorption spectrum is shown in Fig. 2. The spectrum analysis revealed that the high transparency and lower absorption cut off of 240 nm has been achieved in LPA crystal and then there was no absorption from 300nm to 1100nm it can be used for NLO device fabrications. The optical band gap of LPA crystal is shown in Fig. 3. The Energy band gap of LPA crystal is determined using the tauc’s extrapolation method [6]. The band gap energy was found to be 5.2 eV for LPA crystals and thus indicate that the crystals are insulators and that can be used for laser technology.

Fig. 2. UV-vis-NIR Spectrum of LPA single crystal.

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Fig. 3. Energy band gap of LPA single crystal. Dielectric Measurements. The dielectric measurements are one of the basic electrical properties of solids [7]. The study of dielectric constant and dielectric loss of a material gives an introduction about the nature of atoms in the solids, ionic nature and corresponding bonding in the material. The dielectric constant (εr) and dielectric loss (tanδ) values obtained for LPA crystal are shown in Fig. 4 and Fig. 5 respectively. The increase in εr at low frequency may attributed to electric, ionic, orientation and space charge polarization and it decrease at high frequencies due to the loss of significance of these polarization gradually [8]. It has been found that the dielectric parameters (εr and tanδ) values are found to decrease with the increase in frequency. This is a normal dielectric behaviour and it indicates that it can be used for NLO applications.

Fig. 4. Dielectric Constant of LPA Single crystal.

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Fig. 5. Dielectric Loss of LPA Single crystal. Thermal analysis. Thermogravimetric and differential thermal analysis give information about the phase transition of the compound, crystallization of water and different decomposition stages of the crystal [9]. The TG/DTA of grown LPA crystal has been recorded in an atmosphere of nitrogen at a heating rate of 20°C/min in the temperature range of 30–600°C by using CNST thermal analyzer. The initial mass of the material subjected to the analysis was 2.474 mg. The recorded TG/DTA spectrum is shown in the Fig. 6. From the TG curve it is understood that the material is stable up to 157 ºC indicating the absence of water molecules in the samples and hence the crystal rejected solvent molecules during crystallization, and on further heating the material suffers weight loss and it follows one stage weight loss pattern. The maximum decomposition mass loss of the material observed in between 200 ºC and 300 ºC. In the DTA curve, the endothermic peak observed at 154 °C is assigned to the melting point of LPA crystal it shows that the LPA crystal is in good crystalline nature. Hence, the material is stable upto 157 °C and it may be suitable for manufacturing the NLO devices.

Fig. 6. TGA/DTA curve of LPA Single crystal.

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NLO Studies. The second harmonic generation of the grown crystals was examined using the Kurtz and Perry powder technique [10]. The wavelength 1064 nm from a Q-switched Nd: YAG laser with a pulse energy 2.8mJ/pulse, pulse width 8 ns, and repetition rate of 10 Hz was used. The collected green emission from the LPA sample, the output confirms the nonlinear behaviour of LPA crystal. The output signal of 9.93 mJ was obtained for LPA single crystal compared to input signal of reference KDP is 8.91 mJ. Thus, the measured SHG efficiency was found that the grown LPA crystal has nearly 1.12 times higher NLO efficiency than KDP, which is familiar for organic NLO material. Summary. The L-Proline Adipate (LPA) crystals have been grown by slow evaporation method at ambient temperature. The single crystal XRD confirmed the monoclinic symmetry of LPA crystals. The high transparency and lower cut-off wavelength (240 nm) of LPA crystal indicates the prominent potential for NLO device fabrications. The dielectric property studied at room temperature indicates that the dielectric constant and dielectric loss decreases with the increase in frequency. The characteristics of low dielectric loss with high frequency for LPA crystal indicates that the crystal possesses high optical quality with lesser defects and this parameter is vital for various applications of NLO materials. TG/DTA analysis show thermal stability of the materials up to 157°C, which is ambient temperature for NLO application. The existence of second harmonic generation (SHG) signal was observed by using ND: YAG laser with the fundamental wavelength of 1064 nm. References [1] S. Sathiskumar, T. Balakrishnan, K. Ramamurthi, S. Thamotharan, “Synthesis, structure, crystal growth and characterization of a novel semiorganic nonlinear optical L – proline lithium bromide monohydrate single crystal,” Spectrochim Acta A Mol and Biomol Spectrosc, Vol. 138, pp. 187-194, 2015, DOI. 10.1016/j.saa.2014.11.004. [2] A. Kandasamy, R. Siddeswaran, P. Murugakoothan, P. Suresh Kumar, R. Mohan, “Synthesis, Growth, and Characterization of L-Proline Cadmium Chloride Monohydrate (L-PCCM) Crystals: A New Nonlinear Optical Material,” Crystal growth and Design, Vol. 7, pp. 183-186, 2007, DOI: 10.1021/cg060446c. [3] M. Fleck, A.M. Petrosyan, “Difficulties in the Growth and Characterization of Non-Linear Optical Materials, lts of Amino Acids,” Journal of Crystal Growth, Vol. 312, pp. 2284-2290, 2010, DOI.10.1016/j.jcrysgro.2010.04.054. [4] A.M. Britto Dhas, S. Natarajan, “Growth and Characterization of L-Prolinium Tartrate A New Organic NLO Material,” Crystal Research Technology, Vol. 42, pp. 471-476, 2007, DOI. 10.1002/crat.200610850. [5] Sharad Kumar Panday, “Advances in the chemistry of proline and its derivatives: an excellent amino acid with versatile, applications in asymmetric synthesis,” Tetrahedron Asymmetry, Vol. 22, pp. 1817-1847, 2011, DOI. 10.1016/j.tetasy.2011.09.013. [6] D. Kalaiselvi, R. Jayavel, “Synthesis, growth and characterization of L-proline dimercuric chloride single crystals for frequency conversion applications,” Appl Phys A, Vol. 107, pp. 93-100, 2012, DOI. 10.1007/s00339-011-6741-1. [7] P. Kalaiselvi, S. Alfred Cecil Raj, K. Jagannathan, N. Vijayan, G. Bhagavannarayana, S. Kalainathan, “Solid State Parameters, Structure Elucidation, High Resolution X-Ray Diffraction (HRXRD), Phase Matching, Thermal and Impedance analysis on L-Proline trichloroacetate (LPTCA) NLO Single Crystals,” Spectrochim Acta A Mol and Biomol Spectrosc, Vol. 132, pp. 726732, 2014, DOI.10.1016/j.saa. 2014.04.109 [8] N. Renuka, R. Ramesh Babu, N. Vijayan, G. Vasanthakumar, A. Krishna, K. Ramamurthi, “Structural, Optical, Mechanical and Dielectric Studies of Pure and doped L-Prolonium Trichloroacetate Single Crystals,” Spectrochim Acta A Mol and Biomol Spectrosc, Vol. 137, pp. 601606, 2014. DOI. 10.1016/j.saa.2014.08.114 MMSE Journal. Open Access www.mmse.xyz

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[9] J. Thomas Joseph Prakash, S. Kumararaman, “Growth and Characterization of L-Proline cadmium chloride monohydrate single crystals,” Materials Letters, Vol. 62, pp. 4097-4099, 2008, DOI. 10.1016/j.matlet.2008.06.006. [10] S.K. Kurtz, T.T. Perry, “A Powder technique for the evaluation of Nonlinear Optical Materials,” Journal of Applied Physics, Vol. 39(8), pp. 3798-3813, 1968, DOI.10.1063/1.1656857 Cite the paper N. Indumathi, K. Deepa, J. Madhavan, S. Senthil, (2017). Synthesis, Growth and Optical, Electrical, Thermal Properties of L- Proline Adipate Single Crystals for Nonlinear Optical Applications. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.5.76.497

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Synthesis, Growth, Spectral, Thermal and Mechanical Properties of Inorganic – Organic Hybrid NLO Crystal: NH4[Cd(NCS)3] C12H24O627 V. Ramesh1, K. Rajarajan2, a 1 – Department of Physics, SRM University, Vadapalani, Chennai - 6000026, Tamilnadu, India 2 – Department of Physics, Rajeswari Vedachalam Governmen Arts College, Chengalpet - 603001, Tamilnadu, India a – drkrr2007@gmail.com DOI 10.2412/mmse.61.54.732 provided by Seo4U.link

Keywords: solution growth, optical transmission, SHG, micro-hardness and TG-DSC.

ABSTRACT. Ammonium (18-crown-6-ether)cadmium (II) tri-thiocyanate [(NH4[Cd(NCS)3].C12H24O6] (ACCTC) is the potential inorgani-organic hybrid material, which has many applications in the field of laser displays and optical communications. The crystal growth of ACCTC has been carried out by slow evaporation solvent technique (SEST) at ambient temperature and its dimension was found to be 10×5×5 mm 3. The single crystal X-ray diffraction analysis has confirmed the cell parameter of the grown crystal. The FT-IR spectrum is used to identify the functional groups present in ACCTC. The optical transmission is found by UV-Vis-NIR spectrometer. From the optical spectrum, good prominent optical transmission in the entire ultra violet to IR region has been well proved and hence it is an essential requirement for non-linear optical applications. Thermal analysis carried out on ACCTC revealed that it is thermally stable up to 237 °C which is far better than Li[Cd(NCS)3].C12H24O6 (CLTC); 170 ˚C, CdHg(SCN)4 (CMTC); 199 ˚C and Hg(N2H4CS)4Zn(SCN)4 (TMTZ); 185 ˚C. The Vicker’s hardness tester is used to estimate the mechanical hardness of the grown crystal and the results are reported.

Introduction. Recently, Nonlinear opitcal material plays an impartant role in the photonics and optoelectronics. New nonlinear optical (NLO) frequency conversion mateirals have a significant impact on laser technology, optical datastorage and telecommunications. The past few decates, a new series of hybrid nonlinear optical crystal based on polymeric cadmium- thiyocyante anions and complex cations [1-3] have received wide attention due to their good optical and interesting physical properties such as thermal, mechanical and second harmonic generation effects. Renewed attention has been received recently for the polymer, inorganic and organic, materials. IPOS series, thiocyanate (SCN) ligand forms a coordination polymeric chain combined with the d 10 transition metal ion and leads a non-centrosymmetric structure. A novel series of coordination solids explained as IPOS with the general formula [H-G] [M-L], where the inorganic anion [M]- is ligand (L) coordination polymer such as [Cd(SCN)3]∞ and the organic cation [H-G]+ is a host (H)- guest (G) complex such as [(crown ether)-(alkali metl)]. Earlier scientists and researchers [4] reported the growth of a novel hybrid nonlinear optical compound [(18C6)K][Cd(SCN)3], which is wide optically transparent from 220 to 3,300 nm and exhibits efficient SHG. Based on the design theory, attempts were made to combine 18-crown-6 ether (18C6) and thiocyanate ligands with the transition metal ion Cd 2+ and the alkali metal ion NH4+. A new nonlinear optical compound [(NH4)[Cd(NCS)3].C12H24O6] [Ammonium (18crown-6-ether) cadmium (II) tri-thiocyanate, ACCTC] material has been synthesized. Signle crystals of ACCTC with dimension of 10×5×5 mm3 were grown from aqueous solutions via solvent evaporation technique. In this paper, the growth of Ammonium (18-crown-6-ether) cadmium (II) trithiocyanate, (ACCTC) single crystal and its characterization by single crystal XRD, FT-IR, UV-Vis, TG-DSC, SHG and microharness are reported. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Material synthesis. All the starting materials were of analytical reagent, and deionizer water was used in the preparation of the solutions. the raw material for the growth of ACCTC single crystal was synthesized according to following reaction: C12H24O6+CdCl2+3(NH4SCN)

[(NH4)Cd(NCS)3].C12H24O6]+2NH4Cl.

The calculated amount of salts were dissolved in triple distilled water at room temperature, as a result a small precipitation was formed. The mixed solution was filtered and removed the un-dissolved materials by filter paper. Finally, the clear solution was allowed to slowly evaporate at room temperature. After a period of 10-15 days, the small millimetre seed crystals were grown at surface of the liquid. The repeated recrystallization process provides the high quality synthesized compound (ACCTC), which is shown in Fig.1.

Fig.1. Grown crystal of ACCTC. Results and discussion Single crystal XRD. Single crystal X – ray diffraction (XRD) analysis was carried out using a Bruker Kappa APEXII CCD diffractometer with graphite monochromated Mo-Kα radiation (λ = 0.71073 A˚). This paper reports the single crystal growth of [(NH 4)[Cd(NCS)3].C12H24O6]. This compound crystal lies in an orthorhombic unit cell of space group Cmc21 with cell parameter a = 14.7568 Å, b= 15.4378 Å, c = 10.6383 Å, V = 2423.54 (18) Å3 and Z= 4[5]. FTIR studies. The powdered crystal was subjected to FT-IR spectroscopy which, confirm the presence of functional groups and coordination of legends in the wavelength range 400-4000 cm-1 as shown in Fig.2. The prominent absorption of Peaks of ACCTC observed. When it was compared with the spectra of CLTC a few peaks were found to be shifted. The sharp and intense bands observed at 1107.5 and 958.0 cm-1 are shifted from 1100 and 955 cm-1 of CLTC respectively, which is due to CO-C stretching vibration. In addition, the sharp and intense band observed at 1353.2 is shifted from 1349 cm-1 of CLTC, which is due to –CH2- stretching vibration. The CN stretching vibration mode of SCN appears as a very strong and highly intense sharp band at 2120.8 cm-1. The comparison of IR vibrational frequencies of ACCTC and CLTC is presented Table.1.

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Fig.2. FT-IR spectrum of ACCTC crystal. Table 1. Comparison of FT-IR spectral data of ACCTC single crystal with CLTC. Wave number (cm-1) Assignments

ACCTC

CLTC

3249.5

3170

2δ(NH2)

2860.4

29047

νs(NH2)

2746.9

2742

ν(CN)

2120.8

2124,2074

ν(CN)

1674.3

1676, 1622

δ(NH2)

1420.7

1457, 1415

ν1(SCN2 H4)

1353.2

1,349

ν1(SCN2 H4)

1286.3

1282

ν1(SCN2 H4)

1247.1

1249

ν2(SCN2 H4)

1107.5

1100

ν2(SCN2 H4)

958

955

2δ(SCN)

834.4

834

2δ(SCN)

754.9

751

ν(CS)

527.4

531

δas(NCN)

456.3

453

δ(NCN)

Optical studies. The UV-vis-NIR spectrum of ACCTC single crystal recorded in the wavelength range of 200-1200 nm is shown in Fig.3. In ACCTC, the cut off wavelength lies at 220 nm. The absorption is negligible in the entire visible region of the spectrum. Therefore, ACCTC can be used as a potential material for second harmonic generation (SHG).

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3.5

Absorption Intensity (a.u)

3.0

2.5

2.0

1.5

1.0

0.5

0.0 200

400

600

800

1000

1200

Wavelentgh (nm)

Fig. 3. Absorption spectrum of ACCTC single crystal. NLO Test. The NLO efficiency of ACCTC crystal was evaluated by the Kurtz and Perry powder technique using a Q–switched mode locked Nd3+: YAG laser emitting 1.064 µm, 8ns laser pulses with spot radius of 1mm. The input laser beam was passed through an IR reflector and then directed on the powdered sample. The light emitted by the sample was measured by the photo–diode detector and oscilloscope assembly. A microcrystalline material of KDP was used for comparison with ACCTC for the SHG experiment. For a laser input pulse of 2.48 mJ, the second harmonic signal of 22 and 46 mW were obtained through KDP and ACCTC samples, respectively. Hence, it is observed that the SHG efficiency of ACCTC is 2 times superior to KDP.

Fig. 4. TGA-DSC curves of ACCTC single crystal. TG-DSC studies. Thermal stability and physicochemical changes of ACCTC single crystal were studied by thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) using Universal V4.5A TA Instruments. TGA and DTA analysis of ACCTC sample were carried out from room temperature to 1000 °C in nitrogen atmosphere at a heating rate of 20 °C/ min. The TG and DSC curves of ACCTC are shown in Fig.4. The TG curve shows that the decomposition percentage of ACCTC at various temperatures. The TG-DSC thus MMSE Journal. Open Access www.mmse.xyz

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observed is shown in Fig.4. There is a first weight loss starting at about 237Ë&#x161;C. The DTA curve presents several endothermic peaks due to the decomposition and elimination of volatile pyrolysis products. The TG-DSC thermal analysis revealed that the sample is thermally stable up to 237 Ë&#x161;C, which is comparatively far better than the thermal stability of CLTC (170Ë&#x161;C). Microhardness studies. The microhardness measurement is made on well polished ACCTC crystal of dimensions 4x3x3 mm3 by REICHERT MD 4000E ultra microhardness tester with a diamond pyramidal indenter. The applied loads were 10, 25, 50 and 100 g. The indentation time was kept as 10s for each load. The Vickers microhardness number (Hv) was calculated using the standard formula.

đ??ťđ?&#x2018;Ł =

1.8544 đ?&#x2018;&#x192; đ?&#x2018;&#x2018;2

Where Hv is the Vickers hardness number in kg/mm2, P is the applied load in kg and d is the mean diagonal length of the indenter impression in mm. Fig. 5 shows the variation of Vickers hardness (Hv) versus applied load (P) ranging from 10 to 100 g. The result shows the micro hardness value increases with increase of load.

140

Vickerhardness (Kg/mm2)

120

100

20 0

100

Load P (g)

Fig. 5. Variation of Hv with load for ACCTC crystal. Summary. This paper reports the growth of good quality single crystal of [(NH 4) [Cd(NCS)3].C12H24O6] through slow evaporation technique. The grown crystal was characterized by single crystal X-ray diffraction. The structural analysis reveals that ACCTC crystallizes in the space group Cmc21 with cell parameters a = 14.7568 Ă&#x2026;, b= 15.4378 Ă&#x2026;, c = 10.6383 Ă&#x2026;, V=2423.54(18) Ă&#x2026;3 and Z= 4. The presence of function groups and transmittance of ACCTC crystal were analysed by FT-IR and UV-Vis spectral analysis, respectively. The TG-DSC thermal analysis revealed that ACCTC is thermally stable up to 237 Ë&#x161;C, which is comparatively far better than the thermal stability of CLTC (170Ë&#x161;C). Vickers microhardness measurements show that the Vickers hardness increases with increase in load. The above results reveal that ACCTC is a potential material for NLO applications. References MMSE Journal. Open Access www.mmse.xyz

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[1] H. Zhang, D.E. Zelmon, J.Cryst. Growth 234 (2002) 529. DOI: 10.1016/S0022-0248(01)016414. [2] K. Rajarajan, S.Selvakumar, G.P.Joseph, I.Vedha Potheher, M. Gulam Mohamed, P. Sagayaraj, J.Cryst. Growth 286 (2006) DOI: 10.1016/j.jcrysgro. 2005.10.092 [3] C.M. Ragavan, R.Sankar, R.Mohankumar and R. Jayavel J.Cryst. Growth 310 (2008) DOI:10.1016/j.jcrysgro.2008.07.090 [4] J. Zhang, X. Shu, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 74 (2009) 532. DOI:10.1016/j.saa.2009.06.053. [5] V. Ramesh, K. Rajarajan, K. Sendil Kumar, A. Subashini and M. NizamMohideen, Acta Cryst. (2012) E 68 doi: 10.1107/S1600536812004898. [6] V. Ramesh & K. Rajarajan Appl. Phys. B (2013) DOI 10.1007/s00340-013-5444-z. [7] K. Rajarajan, S.Selvakumar, G.P. Joseph, I.Vedha Potheher, M.Gulam Mohamed and P.Sagayaraj, J. Cryst. Growth 286 (2006) 470. DOI:10.1016/j.jcrysgro.2005.10.092. [8] K.Rajarajan, V.Ramesh and K.Sendil Kumar AIP conference proceeding 1349, 1255 (2011)

DOI: 10.1063/1.3606322. [9] S. Kalainathan, P. Nisha Santha Kumari, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 73 (2009) 127. DOI: 10.1016/J.saa.2009.02.005 [10] Alok D. Bokare and Archita Patnaik Cryst. Res. Technology.39 (2004). DOI 10.1002/crat.200310211. Cite the paper V. Ramesh, K. Rajarajan, (2017). Synthesis, Growth, Spectral, Thermal and Mechanical Properties of Inorganic – Organic Hybrid NLO Crystal: NH4[Cd(NCS)3] C12H24O6. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.61.54.732

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Synthesis, Growth and Characterization Aspects of Non-linear Organometallic Single Crystals of BCTZ28 K.Showrilu1, V.Naga Lakshmi2, K.Rajarajan3, a 1 – Research and Development Centre, Bharathiar University, Coimbatore-641046, Tamil Nadu, India 2 – Ch.S.D.St.Theresa’s autonomous College for women,Eluru,West Godawari-534003, Andhra Pradesh, Tamil Nadu, India 3 – Department of physics, Rajeswari Vedachalam Government Arts College, Chengalpattu-603001, Tamilnadu, India a – drkrr2007@gmail.com DOI 10.2412/mmse.82.69.288 provided by Seo4U.link

Keywords: solution growth, orthorhombic system, HPLC.

ABSTRACT. Bis[(18-Crown-6)Potassium][Tetrakis(isothiocyanato)Zinc(II)],[(18C6)K]2 [Zn(SCN)4] (BCTZ), a novel organo-metallic crystal, was grown from ethanol-water mixed solvent by a slow evaporation solvent technique which were found to be crystallized in a non centrosymmetric space group p na21 of an orthorhombic system. The spectroscopic, optical, mechanical properties of [(18C6)K]2 [Zn(SCN)4]; BCTZ were investigated by FT-IR, FT-Raman, UV-Vis-NIR techniques. The hardness of the grown crystal of BCTZ was measured by Vickers hardness measurement tester. The purity of the crystalline compound was verified by HPLC studies. The UV-Vis study reveals that the title compound was optically transparent in the visible region, which is suitable for non-linear optical applications.

Introduction. The application of single crystals in the newest technology is evident from the recent developments in semiconductors, polarizers, transdures and infrared detectors etc. The organometallic thiocyanate complexes are appropriate for recognizing blue-violet light by frequency doubling of laser radiation. The experiments conducted by the eminent scientists all over the world strongly favour the possible use of this class of materials for various non-linear optical applications and photonics device fabrications [1]. It is fascinating to note that the metal thiocynate complex family crystalline compounds suggest a mixture of molecular structures in turn these complexes are capable of efficient frequency conversion of IR radiation to ultraviolet wavelength. In meta thiocynate complexes, the thiocynate has the capability to interconnect metal ions with its own donors S and N [2-4]. Previously, Zhang and Zelmon [5] have reported the growth of a new NLO crystal [(18C 6)K] [Cd(SCN)3]; KCCTC, which is transparent from 220 to 3300 nm and shows second harmonic generation (SHG). Recently, Zhang and Shou [6] and Zhang and Huang [7] have reported the growth and characterization aspects and powder SHG of [(18C6)Li] [Cd(SCN)3]; CLTC, respectively. The thermal and optical properties of ACCTC [(NH4)] [Cd(NCS)3].C12H24O6 was reported by V. Ramesh and K. Rajarajan [8]. In the present work, a nonlinear optical crystalline compound Bis [(18-Crown-6)Potassium] [Tetrakis (isothiocyanato) Zinc (II)]; [18C6(K)]2[Zn(SCN)4]; BCTZ has been synthesized and single crystals of 5x4x3 mm3 were obtained. The structural details of BCTZ were already reported by A.N.Chekhlov [9]. However, the characterization aspects of BCTZ were not reported elsewhere. Hence, in the present case, efforts were made to synthesize and grow the good quality single crystals and thereby © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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the spectral, optical, thermal and mechanical studies were carried out on the sample and reported for the first time. Experimental procedure. The required amount of starting materials of AR grade (purity>98.0%) were purchased and were utilized to grow the single crystals of BCTZ. To synthesize the title compound, 18-Crown-6, potassium thiocynate and Zinc Chloride were taken in the molar ratio 2:4:1 and dissolved in ethanol-water mixed solution (volume ratio 3:1) and stirred thoroughly for three hours to obtain a homogeneous solution and was filtered with WHATMAN 110 µm filter paper. The filtered solution was left to facilitate evaporation. Colorless single crystals of BCTZ were obtained within a week. Characterization. Single crystal X-ray diffraction (SXRD) analysis was carried out on BCTZ using Bruker Kappa APEX11CCD diffractrometer with graphite monochromated M o-Kα radiation (λ=0.71073Å) to determine the lattice parameters. BRUKER IFS 66 V FT-IR spectrometer used to analyze the various functional groups of element. FT-Raman spectrum was recorded in the range 4004000 cm-1 using BRUKEF RFS 27 Raman Spectrometer to know the different types of vibration modes. The TG-DSC analysis of BCTZ was done using SDT Q 600 V20.9 thermal analyzer in the temperature range 30-1000 °C at the rate of 10 K/min. The microhardness measurement of well polished BCTZ crystal of dimension 5x4x3 mm3 was carried out by a REICHERT MD 4000 E ultra microhardness tester with a diamond indentor. The sample was further subjected to high performance liquid chromatography study using HPLC instrument to determine the purity of the grown crystal. Results and discussion Single crystal XRD. BCTZ crystal belongs to the in a non-centrosymmetric orthorhombic system with Pna21 space group. The lattice parameters obtained are a=17.604(4) Å, b=14.190(3) Å, c=17.625(6) Å, V=4403(2) Å, Z=4. The compound consists of one [Zn(NCS)4]2- anion and two hostguest [K(18-crown-6)]+ cations [9], all coupled through one bridging anionic SCN - ligand into a tri nuclear complex molecule [K(18-crown-6)]2[Zn(NCS)4] (Fig. 1)

Fig. 1. Crystal packing of BCTZ along ‘c’ direction. FI-IR analysis. The powdered sample of BCTZ was subjected FT-IR studies to confirm the occurrence of functional groups and coordination of ligands in the wave number range 4004000 cm- 1. The middle IR spectrum of BCTZ is shown in Fig. 2. The present investigation confirms that the CN stretching mode of KSCN appears as a strong and very sharp bond at 2113.98 and 2073.48 cm-1, which indicates that the thiocyanate group is coordinated to the metal ions through nitrogen. MMSE Journal. Open Access www.mmse.xyz

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Similarly, the SCN coordination is evident from the SCN bending observed at 478.58 cm-1. Thus, in the BCTZ sample, the N-bonded nature has been confirmed by FT-IR analysis. The sharp peak bands observed at 1103.28 and 960.55 cm-1 were shifted from 1037 and 940 cm-1 of pure 18-Crown-6 respectively, which is due to symmetric and asymmetric C-O-C stretching vibrations. In addition, the sharp and intense band observed at 1350.17 was shifted from 1333 cm-1 of BCTZ [11], which is due to â&#x20AC;&#x201C;CH2- stretching vibration. The selected FT-IR spectral assignments of BCTZ listed in Table 1.

Fig. 2. FT-IR spectrum of BCTZ. Table 1. Selected FT-IR spectral assignments of BCTZ. Wavenumber (cm-1)

Assignments

478 , 530

NCS symmetric bending vibrations

837

Twice NCS bending vibrations

867

Twice NCS bending vibrations

960

Symmetric C-O-C stretching vibrations

1103

Asymmetric C-O-C stretching vibrations

1452

CH2 Stretching vibrations

1471

CH2 Stretching vibrations

2073

CN stretching vibrations

2113

CN stretching vibrations

2970

NH stretching vibrations

FT-Raman studies. The Raman spectrum obviously shows the vibration modes at 279.09 and 245.53cm-1 respectively, which confirm the coordination of Zn ions with the SCN ligand. In addition, the presence and binding of the SCN is observed as a strong peak observed at 2112.51cm-1 that corresponds to the stretching vibration of CN. From the structure point of view, it is evident that the Zn atoms are tetrahedrally coordinated with four nitrogen atoms (Fig 2). Thermal analysis. The TG-DSC analysis of BCTZ was performed using SDT Q 600 V20.9 thermal analyzer in the temperature range 30-1000 0C at 10 K/min. The TG curve of BCTZ shows the MMSE Journal. Open Access www.mmse.xyz

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decomposition of the sample at various temperatures (Fig 3). In the grown crystal, there is no weight loss up to 1000C, indicating absence of water in the molecular structure BCTZ and the DSC profile shows that the thermally stability of the sample is 210.7 0C.

Fig. 3. TG-DSC profile of BCTZ. Vickers’s Micro hardness. Hardness is the one of the very important physical properties, which can be used as a suitable measure to analyze the strength of the material. The microhardness measurement was carried out on the well-polished BCTZ crystal of dimension 5x4x3 mm3 using REICHERT MD 4000 E ultra micro hardness tester with a diamond indentor. The Vicker’s hardness values of BCTZ were estimated for different applied loads. A graph is drawn with the parameters hardness (Hv) and load (p) as shown in Fig 4. It is clear from the graph that the hardness number increases with increasing load up to 100 g. Hardness attains saturation above 100g, which may be due to the outcome of internal stresses generated locally due to indentation

300

Hv in Kg / mm2

250

200

150

100

50 0

Load (P) in g

Fig. 4. Hardness Vs Load profile of BCTZ. MMSE Journal. Open Access www.mmse.xyz

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HPLC Studies. To realize the purity of the crystalline materials of BCTZ, the sample was subjected to High performance liquid chromatography study using HPLC instrument. The spectrum shows single peak with the retention time of 3.969 minutes with the peak voltage of 490 mv. The peak with high resolution clearly shows that BCTZ sample is pure. UVâ&#x20AC;&#x201C;Vis spectroscopy. The UV-Vis spectra of BCTZ in ethanol-water aqueous solution (volume ratio 3:1) were recorded with 200 - 800 nm wavelength bands. From the spectral profile (Fig 5), it is evident that BCTZ optically good in the visible region including part of IR and UV. The wavelength minimum is found to be 226.4 nm. The absence of absorption in the above mentioned region reveals the suitability of the sample for NLO applications.

Fig. 5. UV-Vis- Absorbance spectrum of BCTZ. Summary. Optically transparent and good quality crystals of BCTZ were grown successfully by slow evaporation method. The crystal structure was analyzed using standard crystallographic procedures. The UV cut-off wavelength is observed to be 226 nm, which is suitable for producing blue-violet light using diode laser. The functional elements of BCTZ were analyzed through FT-IR and FT Raman studies. The low absorption in the visible region shows that these crystals are usable in SHG. Thermal studies reveal that the BCTZ sample stable up to 210.7 0C. The mechanical properties were analyzed. The purity of the compound was confirmed by HPLC technique. From all these studies, it can be concluded that the title compound BCTZ is a potential material for NLO applications. Acknowledgements. One of the authors K. Rajarajan extends sincere thanks & gratitude to University Grants Commission (UGC) and Tamil Nadu State Council for Higher Education (TANSCHE) for funding the research project. The authors acknowledge the Sophisticated Analytical Instrument Facility (SAIF), IIT-Madras and VIT, Vellore for the facilities extended towards characterization. References [1] K. Rajarajan, S. Selva kumar, Ginson P.Joseph, I.Vetha Pother, M.Gulam Mohamed, P. Sagayaraj J., Crst.Growth 286 (2006) 470 DOI: :10.1016/j.jcrysgro.2005.10.092. [2] I. Vetha Potheher, K. Rajarajan, M. Vimalan, S. Tamilselvan, R. Jeyasekaran, P. Sagayaraj, Phys. B 406, (2011) 3210 DOI:10.1016/j.physb.2011.05.025. [3] A. Gacemi, D. Benbertal, B.B. Muriel, A. Lecchi, A. Mosset, Z. Anorg. Allg. Chem. 629, (2003) 2516 DOI: 10.1002/zaac.200300243. [4] X.T. Liu, X.Q. Wang, X.J. Lin, G.H. Sun, G.H. Zhang, D. Xu, Appl. Phys. A 107(2012) 949 DOI: 10.1007/s00339-012-6829-2. MMSE Journal. Open Access www.mmse.xyz

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[5] H. Zhang, D.E. Zelmon, J. Cryst. Growth 234 (2002) 529. [6] J.J. Zhang, X. Shou, Spect. Chimi. Acta Part A Mole. Biomole.Spect. 74 (2009) 532. [7] J.J. Zhang, Y. Huang, Powder second harmonic generation measurement and thermal decomposition mechanisms of a new organometallic compound [(18C6)Li][Cd(SCN)3], Cryst. Res. Technol. 44 (2009) 985, DOI: 10.1002/crat.200900047 [8] V. Ramesh, K. Rajarajan, Crystal growth and characterization of a novel inorganic-organic hybrid NLO crystal: (NH4)[Cd(NCS)3]ÂˇC12H24O6, Appl. Phys. B, 113 (2013) 99, DOI: 10.1007/s00340013-5444-z [9] A.N. Chekhlov, Bis[(18-crown-6)potassium] tetrakis(isothiocyanato)zinc(II): synthesis and crystal structure, Russian J. of Inorg. Chem. 53 (2008) 780, doi:10.1134/S0036023608050185 [10] X.Q. Wang, D. Xu, M.K. Lu, D.R. Yuan, S.X .Xu, Mater Res Bull 36(2001), 879. [11] H. Zhang, X. Wang,H. Zhu,W. Xiau, B.K. Tes, Inorg.Chem. 38 (1999) 886. Cite the paper K. Showrilu, V. Naga Lakshmi, K. Rajarajan, (2017). Synthesis, Growth and Characterization Aspects of Nonlinear Organometallic Single Crystals of BCTZ. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.82.69.288

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Crystal Growth, Spectral and Optical Properties of Quinolinium Single Crystal: 1-Ethyl-2-[2-(4-Nitro-Phenyl)-Vinyl]-Quinolinium Iodide29 S. Karthigha1, C. Krishnamoorthi1,a 1 – Department of Physics, School of Advanced Sciences, VIT University, Vellore – 632 014, India a – krishnamoorthi.c@vit.ac.in DOI 10.2412/mmse.21.75.127 provided by Seo4U.link

Keywords: organic crystals, crystal growth, powder XRD, FTIR and photoluminescence.

ABSTRACT. N-Ethyl quinolinium derivative of PNQI has been successfully synthesized by knoevenagel condensation reaction and purified by repeated recrystallization process. The single crystal of title material was grown by slow evaporation technique using methanol as a solvent. The crystallinity of grown crystal was confirmed by powder X-ray diffraction analysis. Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopic studies were performed for the identification of functional groups present in the grown crystal. The linear optical property of the grown crystal was studied by UV-Vis-NIR spectral analysis. The photoluminescence spectrum of title crystal PNQI exhibits prominent emission peak at 567 nm.

Introduction. Synthesis and design of new organic molecules with high nonlinear optical susceptibilities have been investigated due to their potential applications in telecommunications, optical computing, optical data storage, bioimaging and optical information processing [1]. In order to satisfy the day to day technological requirements, new organic nonlinear materials are mandatory which exhibits large nonlinear response compare to inorganic counterparts due to the presence of large polarisable π-conjugated system. Recently it has been found that the ionic organic stilbazolium family crystals are of considerable attention due to their large second and third order optical nonlinearities. In this series, quinolinium derivatives are one of the stilbazolium family and many researchers made an attempt to grow quinolinium derivative single crystals, because it possesses a large number of conjugated π-electrons exhibits high nonlinear optical properties. Generally, the heteroaromatic salt type electron acceptors show high electron withdrawing strength and lead to large nonlinear optical response [2]. Thus these compounds take quinolinium moiety as an electron acceptor and, their crystal phase exhibits attractive characteristics such as high macroscopic nonlinearity, advantageous spatial arrangements, high environmental stability and optical quality [3]. In the present work, we report the material synthesis, growth, spectral and optical properties of PNQI. Synthesis and Crystal growth. The quinolinium derivative PNQI was synthesized by taking equimolar ratio of 1-ethyl-2-methyl quinolinium iodide and 4-nitro benzaldehyde in methanol solution and piperidine is added as a catalyst. The solution was refluxed for 35mins using round bottomed flask. Further the solution was cooled to room temperature and the red coloured PNQI product was collected and the salt was dried in hot air oven at 100 0C for an hour. The final product was purified by repeated recrystallization process using methanol. In order to grow the PNQI single crystals, a saturated solution was prepared at room temperature. After slow evaporation of solvent over a period of 25 days, the spontaneous nucleation was occurred in the supersaturated solution and the single crystals of PNQI have been harvested. The grown crystal is shown in Fig 1.

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Fig. 1. As grown crystal of PNQI. Results and Discussion Powder X-ray diffraction analysis. The fine powder of grown crystals has been characterized by using Bruker X-ray diffractometer with CuKα radiation (1.5405 Å) to identify the crystalline nature and reflection planes. The sample was recorded in the range of 10-500 at a scanning rate of 0.020S-1. Powder XRD pattern was investigated by using powder X software program. Fig 2 shows that the well defined Bragg’s peaks at specific 2θ angles confirm good crystalline property of the grown PNQI crystal. The single crystal XRD analysis has carried out using Bruker Kappa APEX II diffractometer with MoKα radiation of wavelength λ=0.71073 Å at room temperature. The title material crystallized in triclinic crystal system with space group P-1 and the lattice parameters were determined to be a=8.66423(8) Å, b=9.9639(10) Å, c=10.1012(9) Å, α=85.648(5)0, β=83.440(5)0, γ= 87.782(5)0.

Fig. 2. Indexed powder XRD pattern of PNQI.

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Proton NMR. 1H NMR (400 MHz, DMSO-d6): δ= 8.063-8.236 (d, H-1’), 8.277-8.319 (d, H-2’), 8.002-8.039 (t, H-6), 8.236-8.255 (t, H-7), 8.443-8.446 (d, H-5), 8.626-8.641 (d, H-8), 8.648-8.664 (d, H-3),9.200-9.222 (d, H-4), 8.381-8.403 (d,H-2’’,6’’), 8.423-8.426 (d, H-3’’,5’’), 1.581-1.616 (t, NC2H5), 5.207-5.260 (m, NC2H5) Carbon NMR.13C NMR (400 MHz, DMSO-d6): δ= 14.82, 39.38, 39.59, 39.80, 40.00, 40.21, 40.42, 40.36, 47.81, 119.67, 122.37, 123.32, 124.62, 129.26, 130, 130.61, 131.03, 136.11, 138.63, 141.40, 144.69, 145.76, 148.86, 155.25. Fourier Transform Infrared Spectral analysis. The characteristics vibrational modes and functional groups present in PNQI were analysed by FTIR spectroscopic technique. The spectrum was recorded in the range of 400-4000 cm-1 using an SHIMADZU IRAFFINITY spectrometer. From Fig. 3 it was observed that the peak appears at 3057.16 and 3016.67 cm-1 are ascribed to aromatic CH stretching vibrations. The alkyl C-H stretching mode is observed at 2939.52 cm-1. The absorption peak at 1570.16 cm-1 is assigned to olefinic C=C stretching vibration and the peaks that were observed at 1734.01 and 1598.99 cm-1 are due to the aromatic C=C stretching vibrations. The peak observed at 1078 cm-1 is corresponds to the olefinic =C-H bond. Absorption peaks observed around 1440.83 and 1516.06 cm-1 corresponds to the symmetric and asymmetric stretching of nitro (NO 2) group, which confirms the formation of the title material. Thus all the functional groups present in the crystal structure of PNQI has been confirmed.

Fig. 3. FTIR spectrum of PNQI. UV-Vis-NIR spectral analysis. The absorption spectrum of PNQI was recorded for the wavelength range of 200- 1100 nm. The recorded spectrum is shown in Fig. 4. The optical transparency is high in near IR region of the spectrum and there is no significant absorption between 506-1100 nm. The cut-off wavelength of grown crystal is 506 nm, which is assigned to π- π* transition contributed by extended conjugation in the stilbazolium chromophore.

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Fig. 4. Absorption spectrum of PNQI. Photoluminescence Analysis. Photoluminescence studies are highly preferred to detect the lower concentrations of defects. Since the impurity on absorption of light gives rise to the bound excited state, which it returns to its ground state abiding in the analysis of colour centre creation mechanism [5]. The emission spectrum of PNQI was recorded using Jobin-Yvon spectrophotometer at room temperature and 450 W high pressure xenon lamp was used as an excitation source. The photoluminescence spectrum was measured in the range of 550- 580 nm and the sample was excited at 480 nm. The recorded luminescence spectrum of PNQI was shown in Fig. 5. From the emission spectrum, the broad emission peak observed at 567 nm which corresponds to the mobility of π electrons between p-nitro anion and the quinolinium cation through stilbazolium chromophore. Thus, this indicates the band appeared at 567 nm owing to the emission of green radiation and is high importance for opto electronic and solid state lighting applications [4]. The band gap of energy was calculated using the formula, Eg = hc/ λe. The band gap energy calculated is about 2.18 eV for PNQI crystal.

Fig.5. Emission spectrum of PNQI.

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Summary. An organic single crystal of PNQI was grown by slow evaporation method. Powder XRD reveals the crystalline nature of grown crystal and Single crystal X-ray diffraction study confirms that the PNQI crystal belongs to triclinic crystal system. The molecular formation of title material was confirmed by using FTIR and NMR spectroscopic studies. The UV-Vis spectroscopy study shows that the crystal cut-off wavelength at 506 nm and the emission behaviour of PNQI was confirmed by Photoluminescence analysis. References [1] Jebin, R. P., Suthan, T., Rajesh, N. P., Vinitha, G., & Dhas, S. B. (2016). Studies on crystal growth and physical properties of 4-(dimethylamino) benzaldehyde-2, 4-dinitroaniline single crystal. Optical Materials, 57, 163-168, DOI.10.1016/j.optmat.2016.04.030. [2] Lee, S. H., Yoo, B. W., Yun, H., Jazbinsek, M., & Kwon, O. P. (2015). Organic styryl quinolinium crystal with aromatic anion bearing electron-rich vinyl group. Journal of Molecular Structure, 1100, 359-365, DOI.10.1016/j.molstruc.2015.07.071. [3] Kim, J. S., Lee, S. H., Jazbinsek, M., Yun, H., Kim, J., Lee, Y. S., & Kwon, O. P. (2015). New phenolic N-methylquinolinium single crystals for second-order nonlinear optics. Optical Materials, 45, 136-140, DOI. 10.1016/j.optmat.2015.03.023. [4] Mansour, N., Momeni, A., Karimzadeh, R., & Amini, M. (2012). Blue-green luminescent silicon nanocrystals fabricated by nanosecond pulsed laser ablation in dimethyl sulfoxide. Optical Materials Express, 2(6), 740-748, DOI. 10.1364/OME.2.000740. [5] Singh, B. K., Sinha, N., Singh, N., Kumar, K., Gupta, M. K., & Kumar, B. (2010). Structural, dielectric, optical and ferroelectric property of urea succinic acid crystals grown in aqueous solution containing maleic acid. Journal of Physics and Chemistry of Solids, 71(12), 1774-1779, DOI. 10.1016/j.jpcs.2010.09.010. Cite the paper S. Karthigha, C. Krishnamoorthi, (2017). Crystal Growth, Spectral and Optical Properties of Quinolinium Single Crystal: 1-Ethyl-2-[2-(4-Nitro-Phenyl)-Vinyl]-Quinolinium Iodide. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.21.75.127

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Synthesis, Growth, Spectral, Optical and Mechanical Properties of an Organic Single Crystal: (E)-2-(4-Chlorostyryl)-1-Methylpyridin-1-Ium Iodide Hydrate30 K. Nivetha1, W. Madhuri1,a 1 – Ceramic Composite Laboratory, School of Advanced Sciences, VIT University, Vellore, Tamilnadu, India a – madhuriw12@gmail.com DOI 10.2412/mmse.28.97.639 provided by Seo4U.link

Keywords: stilbazolium derivative, nonlinear optical material, slow evaporation, hardness, Z-scan technique.

ABSTRACT. An organic stilbazolium derivative of (E)-2-(4-chlorostyryl)-1-methylpyridin-1-ium iodide hydrate (CMPI) crystal was grown from the methanol-acetonitrile mixed solvent by slow evaporation technique at room temperature. The crystal system and cell parameters of the grown crystal are verified by single crystal X-ray diffraction analysis. The functional groups of CMPI were identified from FTIR spectrum. The optical behaviour of the grown crystal was analysed by UV-vis-NIR studies. The mechanical stability of the grown crystal was investigated by Vicker’s microhardness tester. The third-order nonlinear optical property of the grown crystal was elucidated by employing the single beam Z-scan technique.

Introduction. The nonlinear optical (NLO) properties of organic molecular materials have been the object of intense research due to potential applications in various photonic technologies. Organic molecules with significant NLO behaviour originate from a strong donor-acceptor intermolecular interaction with high chromophore density and delocalised π-electron system [1]. Normally organic chromophores exhibit high and fast nonlinearities than their inorganic counterparts. The stable packing of chromophores in organic crystals, which in turn results in high thermal, mechanical and photochemical stability [2]. Stilbazolium derivatives are found to be the interesting groups of organic materials because their molecular nonlinearity can be easily preserved by varying the counter-ions to achieve the desired physical and chemical properties [3]. Among them, the organic stilbazole crystal, 4-N,N-dimethylamino-4’-N’-methylstilbazolium tosylate (DAST) is of wide interest owing to its outstanding NLO properties and electro-optical properties [4]. The variation of counter-ions in stilbazolium salt is a simple and highly successful method to create new materials with macroscopic optical nonlinearities [5]. These points motivated us to design and synthesis stilbazolium crystals having a π-conjugated system with the good nonlinear response. Though the information about the X-ray crystallographic structural data of (E)-2-(4-chlorostyryl)-1-methylpyridin-1-ium iodide hydrate (CMPI) is available, there is no report on the growth of this material for NLO applications. Hence, we report in this present investigation synthesis, growth, spectral, optical, mechanical, and third-order nonlinear optical properties of the organic stilbazolium derivative, CMPI. Material synthesis and crystal growth. CMPI was synthesized by the Knoevenagel condensation of 1, 2 dimethyl pyridinium iodide and 4-chloro benzaldehyde taken in equimolar ratio and dissolved in methanol (10 ml) in the presence of piperidine as a catalyst. The resulting mixture was refluxed for 8 h until it crystallizes as yellow salt. The product was purified by successive recrystallization from methanol. CMPI single crystals of size 6x2x1.5 mm3 were grown from the saturated solution of CMPI in methanol: acetonitrile (1:1) mixed solvent by slow evaporation technique over a period of 30 days (Fig. 1). © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Fig. 1.Photograph of CMPI crystals. Results and Discussion. Single crystal X-ray diffraction analysis. The XRD study confirmed the monoclinic crystal structure of CMPI with centrosymmetric space group P2 1/C. The lattice parameters obtained are a = 7.1043(1) Å, b=9.7805 (2) Å, c=21.0801 (4) Å, β= 95.279 (1) o and V= 1460.24 (5) Å3. The obtained results are in concurrence with the literature [6] and thus confirm the identity of CMPI. FTIR Spectral analysis. The FTIR spectrum for CMPI crystal was recorded in the KBr pellet phase in the frequency region of 4000-400 cm-1 shown in Fig. 2. The spectrum confirms the formation of CMPI crystal and the characteristic frequencies and the corresponding assignments are given in Table 1. Table 1. Spectral data and their assignments for CMPI. Wavenumber (cm-1)

Assignments

3500.80 and 3383.14

O-H stretching

3070.68 and 3041.74

Aromatic C-H stretching

2945.30, 2916.37 and 2791

Alkyl C-H stretching

1616.35

Olefinic C=C stretching

1568.13 and 1514.12

Aromatic ring vibrations

1489.05, 1458.18 and 1409.96

CH2 bending

1338.60, 1284.59 and 1269.16

C-N stretching

1083.99

Olefinic =C-H bond

1000-1200 and 850-1000

Aromatic C-H inplane and out of plane bending

731.02, 769.60, 815.89, 833.25

C-Cl stretching

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Fig. 2. FTIR spectrum of CMPI. UV-vis-NIR spectral analysis. The optical absorption spectrum of CMPI as recorded for the wavelength range of 220–1000 nm is depicted in Fig. 3. The spectrum shows two absorption peaks, one at 260 nm corresponds to n-π* transition and the other at 340 nm corresponds to the π-π* transition of the stilbazolium chromophore. Moreover, negligible absorption can be seen in the entire region of 341-1000 nm suggests that the grown crystals of the title material are suitable for various nonlinear optical applications.

Fig. 3. Absorption spectrum of CMPI. Vickers microhardness studies. Microhardness measurement was carried out on CMPI single crystals using Vickers microhardness tester fitted with a diamond pyramidal indenter. The diagonal length of the indentation in μm for various applied loads in kg was measured for the constant indentation time of 10 s. The Vickers hardness number (Hv) was computed using the formula, Hv=1.8544 P/d2. The variation of Hv with load (P) Fig. 4 shows that Hv increases with increase in P due to reverse indentation size effect. The Meyer index ‘n’ is estimated from the graph plotted against log P vs. log d (Inset of Fig .4). Thus, the ‘n’ value of 4.26 shows the softness nature of the grown crystal satisfying Onitsch results [7].

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Fig. 4. Variation of Hv with load P and Meyer’s plot of CMPI(inset). Z-scan studies. The third-order NLO property of CMPI crystal was measured by the single beam Zscan technique with the laser light 632.8nm from He-Ne laser was used. The open and closed aperture Z-scan methods were used for the measurement of nonlinear absorption coefficient (β) and nonlinear refractive index (n2) for optical materials. The output beam has a Gaussian intensity profile and was focused, using a convex lens of 30 mm focal length, to a waist of radius (ω o) 12.05 μm, which corresponds to a Rayleigh length of 0.72 mm. The sample thickness of 0.60 mm was less than the Rayleigh length (L<ZR) and hence it could be treated as a ‘thin medium’. The sample is translated in the Z-direction along the axis of a focused Gaussian beam using a motorized translation stage. The transmittance change through a small aperture at the far field position (closed aperture) can determine the amplitude of phase shift. The intensity dependent absorption is measured by moving the sample through the focus without placing an aperture at the detector (open aperture). In the open aperture pattern (Fig.5a), the decrease in transmission near the focus is an indicative of reverse saturable absorption (RSA) with a positive nonlinear absorption coefficient. In the closed aperture pattern (Fig.5b), the valley-peak configuration implies that the sign of refraction nonlinearity is positive (n2>0) i.e. self-focusing effect. The third order nonlinear optical parameters of CMPI crystal are calculated according to the reported literature [1,8]. Table 2 lists the experiment results of the thirdorder NLO parameters of the CMPI crystal. Here the nonlinear optical response arises due to strong delocalization of π-electrons within the molecular structure of CMPI.

Fig. 5. Open aperture and Closed aperture Z-scan plot of CMPI crystal.

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Table 2. Third-order NLO parameters of CMPI. 3.04 x10-5 m/W

Nonlinear absorption coefficient (β)

4.63 x10-12 m2/W

Nonlinear refractive index (n2) Third-order nonlinear optical susceptibility (χ (3))

4.90 x10-5 esu

Summary. Single crystals of organic stilbazolium derivative, CMPI was grown by slow evaporation technique and characterized using single crystal XRD, FTIR, UV-vis-NIR studies, microhardness and Z-scan studies. The results of the above studies reveal that the CMPI crystal might be a potential candidate for NLO applications. References [1] Dhanaraj, P. V., Rajesh, N. P., Vinitha, G., & Bhagavannarayana, G. (2011). Crystal structure and characterization of a novel organic optical crystal: 2-Aminopyridinium trichloroacetate. Materials Research Bulletin, 46, 726-731. DOI: 10.1016/j.materresbull.2011.01.013. [2] Yin, J., Li, L., Yang, Z., Jazbinsek, M., Tao, X., Günter, P., & Yang, H. (2012). A new stilbazolium salt with perfectly aligned chromophores for second-order nonlinear optics: 4-N,NDimethylamino-4′-N′-methyl-stilbazolium3-carboxy-4-hydroxybenzenesulfonate. Dyes and Pigments, 120-126. DOI: 10.1016/j.dyepig.2011.12.004. [3] Yang, Z., Jazbinsek, M., Ruiz, B., Aravazhi, S., Gramlich, V., & Günter, P. (2007). Molecular engineering of stilbazolium derivatives for second-order nonlinear optics. Chemistry of materials, 19, 3512-3518. DOI: 10.1021/cm070764e. [4] Adachi, H., Taniuchi, T., Yoshimura, M., Brahadeeswaran, S., Higo, T., Takagi, M., & Nakanishi, H. (2004). High-quality organic 4-dimethylamino-n-methyl-4-stilbazolium tosylate (DAST) crystals for THz wave generation. Japanese journal of applied physics, 43, L1121. DOI: 10.1143/JJAP.43.L1121. [5] Yang, Z., Aravazhi, S., Schneider, A., Seiler, P., Jazbinsek, M., & Günter, P. (2005). Synthesis and Crystal Growth of Stilbazolium Derivatives for Second‐Order Nonlinear Optics. Advanced Functional Materials, 15, 1072-1076.DOI: 10.1002/adfm.200500036. [6] Chanawanno, K., Chantrapromma, S., & Fun, H. K. (2008). 2-[(E)-2-(4-Chlorophenyl) ethenyl]1-methylpyridinium iodide monohydrate. Acta Crystallographica Section E: Structure Reports Online, 64(10), o1882-o1883. DOI: 10.1107/S1600536808027724. [7] Jagannathan, K., Kalainathan, S., & Gnanasekaran, T. (2007). Microhardness studies on 4dimethylamino-N-methyl 4-stilbazolium tosylate (DAST). Materials Letters, 61, 4485-4488. DOI: 10.1016/j.matlet.2007.02.033. [8] Nivetha, K., Kalainathan, S., Yamada, M., Kondo, Y., & Hamada, F. (2016). Investigation on the growth, structural, HOMO–LUMO and optical studies of 1-ethyl-2-[2-(4-hydroxy-phenyl)-vinyl]pyridinium iodide (HSPI)–a new stilbazolium derivative for third-order NLO applications. RSC Advances, 6(42), 35977-35990. DOI: 10.1039/c6ra02544g. Cite the paper K.Nivetha, W.Madhuri (2017). Synthesis, Growth, Spectral, Optical and Mechanical Properties of an Organic Single Crystal: (E)-2-(4-Chlorostyryl)-1-Methylpyridin-1-Ium Iodide Hydrate. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.28.97.639

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Theoretical Investigation of Optical and Mechanical Properties of Sodium Hydrogen Succinate Single Crystal: a Third Order NLO Material31 P.S. Latha Mageshwari1, R. Priya1, R. Subhashini1, V. Joseph2, S. Jerome Das2, a 1 â&#x20AC;&#x201C; Department of Physics, R. M. K. Engineering College, Kavaraipettai, 601 206, India 3 â&#x20AC;&#x201C; Department of Physics, Loyola College, Chennai 600 034, India a â&#x20AC;&#x201C; sjeromedas2004@yahoo.com, jerome@loyolacollege.edu DOI 10.2412/mmse.39.34.912 provided by Seo4U.link

Keywords: single XRD, ICP-OES, NMR, optical properties, mechanical properties.

ABSTRACT. Sodium hydrogen succinate (SHS), an alkali metallo-organic third order NLO single crystals were grown successfully using aqueous solution by slow evaporation technique at room temperature. Single crystal X-ray diffraction analysis reveals that the grown crystal belongs to monoclinic system with space group C2/c. The presence of sodium in the title compound was confirmed by ICP-OES analysis. The existence of proton and carbon peak in the material was detected using NMR analysis. Using optical absorption studies, the theoretical calculations such as refractive index, reflectance, electrical conductivity, electrical susceptibility and optical conductivity of SHS were determined. The mechanical properties like brittleness index, fracture toughness, yield strength and elastic stiffness coefficient were estimated using Vickers microhardness test. The ac, dc conductivity and activation energy of SHS were also found using dielectric studies at different temperatures.

Introduction. The recent developments in the field of optoelectronics and photonics has made most of the researchers to identify novel materials with most efficient NLO features like second and third order harmonics as per their requirements on the hyperpolarizabilities of molecules [1]. At present large quantity of organic compounds has been materialized as a favorable third order NLO material with large optical susceptibilities, ultrafast response times and high optical threshold for laser power. Organic materials have huge range of remarkable properties and it is more superior to inorganic materials due to Ď&#x20AC; conjugation between electron donor and acceptor groups, chirality and hydrogen bonding. The acceptor-donor groups are commonly attached to organic conjugated systems to produce NLO materials with large hyperpolarizabilities and to mold their transparency [2]. Crystal growth. Succinic acid and sodium hydroxide (AR grade) were mixed in equimolar ratio (1:1) using double distilled water and kept for slow evaporation in dustproof atmosphere. A transparent good quality single crystal Sodium hydrogen succinate (SHS) has been harvested within a period of one month [3]. ICP-OES analysis. To determine the concentration of the alkali metal present in the grown crystal, inductively coupled plasma optical emission spectrometry (ICP-OES) analysis was carried out using ICP-OES spectrometer (Perkin Elmer Optima 5300 DV) that shows a characteristic wavelength at 589.592 nm which is the fingerprint for alkali metal (Na) with 510 mg/L concentration. đ??&#x2021; đ?&#x;? đ???MR and đ??&#x201A; đ?&#x;?đ?&#x;&#x2018; đ???đ??&#x152;đ??&#x2018;. H1 NMR and C13 NMR spectra of title compound recorded with a BRUKER AVIII Spect instrument with 500 MHz and D2O as solvent. The peak recorded at Î´ = 2.5 ppm confirms the presence of chemically, magnetically identical -CH2 â&#x20AC;&#x201C;proton and in C13 NMR the peak around

ÂŠ 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Î´=31 ppm indicated the presence of methyl carbon (C2, C3) and peak at Î´ = 179.7 ppm authenticate the presence of carboxyl carbon (COO -) (C1, C4). Optical properties. The optical absorption is the most useful tool to understand the band gap of optical materials. The optical absorption spectrum of SHS single crystal was recorded in the wavelength range from 200 to 2000 nm using polished sample of thickness 1mm. SHS crystal has very low absorbance in the considerable region of wavelength and the cut-off wavelength was found 1 1 to be 298 nm. The absorption coefficient (Îą) was calculated using the relation, đ?&#x203A;ź = d log (T) ,where T is the transmittance and d is the thickness of the grown crystal. The absorption coefficient (Îą) obeys 1

A(hÎ˝â&#x2C6;&#x2019;Eg )2

the following Taucâ&#x20AC;&#x2122;s relation for high photon energies, Îą = , where Eg is the optical band hÎ˝ gap and A is a constant. Extinction coefficient (K) can be obtained from the following equation, đ?&#x153;&#x2020;đ?&#x203A;ź

K=4đ?&#x153;&#x2039;

(1)

The reflectance in terms of Îą, R=1Âą

â&#x2C6;&#x161;1â&#x2C6;&#x2019;exp(â&#x2C6;&#x2019;đ?&#x203A;źđ?&#x2018;Ą)+exp (đ?&#x203A;źđ?&#x2018;Ą) 1+exp(â&#x2C6;&#x2019;đ?&#x203A;źđ?&#x2018;Ą)

â&#x2C6;&#x2019;(đ?&#x2018;&#x2026;+1)Âąâ&#x2C6;&#x161;3đ?&#x2018;&#x2026;2 +10đ?&#x2018;&#x2026;â&#x2C6;&#x2019;3

The refractive index, n=

4.00E+010

2(đ?&#x2018;&#x2026;â&#x2C6;&#x2019;1)

1.20E+008

3.00E+010

Electrical Conductivity

Optical Conductivity

1.00E+008

3.50E+010

8.00E+007 6.00E+007 4.00E+007 2.00E+007

2.50E+010

0.00E+000 1

2 3 4 5 Photon energy

2.00E+010 1.50E+010 1.00E+010 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Photon Energy (eV)

Fig. 1. Plot of Optical Conductivity versus hÎł.

Fig. 2. Plot of refractive index versus hÎł.

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The optical conductivity of grown crystal can be calculated using the equation [4], đ?&#x153;&#x17D;=

đ?&#x203A;źđ?&#x2018;&#x203A;đ?&#x2018;?

(4)

4đ?&#x153;&#x2039;

where c is the velocity of light and n is the refractive index. Fig. 1 shows the optical conductivity is minima for lower photon energies and then increases with increasing photon energies. Fig.1b implies a clear manifestation that the lower value of electrical conductivity at higher photon energy is due to the dielectric nature of the material. Fig. 2 shows that the refractive index of the medium changes with the incident photon energy and it increases linearly with increasing energy beyond 4.5 eV. Fig. 2 indicates the refractive index decreases abruptly as the wavelength increases and gets saturated beyond the wavelength of 1200 nm.

2.6 2.6

2.2

2.1

Reflectance

2.0

Reflectance

2.2

2.4

1.8 1.5

1.8

1.2

400

800 1200 1600 2000 Wavelength

2.0

Absorption coefficient

2.4

1.2

2.4

2.7

0.8

0.4

0.0 4.0

4.5

5.0 5.5 6.0 Photon energy (eV)

6.5

1.8 1.6

1.6

1.4

1.4 1

3 4 5 6 Photon energy (eV)

1.2 0.4

0.6

0.8

1.0

1.2

Absorption coefficient

Fig. 3. Plot of Reflectance versus hÎł.

Fig. 4. Plot of Reflectance versus Îą.

Fig.3a. depicts the variation of reflectance with photon energy. From the plot it is observed that the reflection coefficient first increases with increase in photon energy and reaches a maximum value at the photon energy 5 eV and then increase slightly with increasing photon energy. Fig.3b shows the high value of reflectance in the wavelength range of 200-300 nm and then remains almost constant up to 2000 nm. From Fig.4a, the variation of reflectance as a function of absorption coefficient, shows clearly that reflectance increases with the absorption coefficient gradually upto 1.2 cm-1 and abruptly changed afterwards. Fig.4b. shows the absorption coefficient varies from 0.1 -1.1 cm-1 with increasing photon energy of 6.6- 8eV. From the above graphs, it is clear that the conductivity, refractive index and reflectance depend on the photon energies. As photon energy determines the internal efficiency of the device by tailoring the photon energy one can achieve the desired material to fabricate the optoelectronic devices [5]. The electric susceptibility (Ď&#x2021; c) was calculated using the following equation, đ?&#x153;&#x20AC;đ?&#x2018;&#x; = đ?&#x153;&#x20AC;0 + 4đ?&#x153;&#x2039;đ?&#x153;&#x2019;đ?&#x2018;? = đ?&#x2018;&#x203A;2 â&#x2C6;&#x2019; đ?&#x2018;&#x2DC; 2 đ?&#x153;&#x2019;đ?&#x2018;? =

đ?&#x2018;&#x203A; 2 â&#x2C6;&#x2019;đ?&#x2018;&#x2DC; 2 â&#x2C6;&#x2019;đ?&#x153;&#x20AC;

4đ?&#x153;&#x2039;

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where đ?&#x153;&#x20AC;0 is the dielectric constant. At đ??&#x20AC; = 1000 nm, the electric susceptibility đ?&#x153;&#x2019;đ?&#x2018;? is 0.012. The complex dielectric constant is given by đ?&#x153;&#x20AC; = (đ?&#x2018;&#x203A; + đ?&#x2018;&#x2013;đ?&#x2018;&#x2DC; )2 = đ?&#x2018;&#x203A;2 â&#x2C6;&#x2019; đ?&#x2018;&#x2DC; 2 + 2đ?&#x2018;&#x2013;đ?&#x2018;&#x203A;đ?&#x2018;&#x2DC; = đ?&#x153;&#x20AC;đ?&#x2018;&#x; + đ?&#x2018;&#x2013;đ?&#x153;&#x20AC;đ?&#x2018;&#x2013;

(7)

where n is the refractive index and k is the extinction coefficient respectively. đ?&#x153;&#x20AC;đ?&#x2018;&#x; and đ?&#x153;&#x20AC;đ?&#x2018;&#x2013; are the real and imaginary parts of the dielectric constant, calculated by the following equation, đ?&#x153;&#x20AC;đ?&#x2018;&#x; = đ?&#x2018;&#x203A;2 â&#x2C6;&#x2019; đ?&#x2018;&#x2DC; 2 and đ?&#x153;&#x20AC; đ?&#x2018;&#x2013; = 2đ?&#x2018;&#x203A;đ?&#x2018;&#x2DC;

(8)

At đ??&#x20AC; = 1000 nm, the real (đ?&#x153;&#x20AC;đ?&#x2018;&#x; ) and imaginary (đ?&#x153;&#x20AC; đ?&#x2018;&#x2013; ) dielectric constant values are 0.16 and 2.5432Ă&#x2014; 10â&#x2C6;&#x2019;7 respectively. Mechanical Properties. The mechanical strength of SHS crystal was carried out using the instrument MATSUZAWA MMTX- 7 SERIES. The Vickers hardness number (Hv ) was calculated using the 1.8544 P relation, Hv = d2 kg mm-2. The variation of Hv with applied load for SHS crystal increases with the increasing load according to reverse indentation effect (RISE). The plot log P versus log d for SHS crystal yields a straight line and slope of it gives the work hardening exponent n whose value is found to be 2.74. Since the value of n is greater than 2 it is concluded that SHS is a soft type material. From Meyerâ&#x20AC;&#x2122;s law, P = K1 dn, where K1 is the standard hardness can be obtained from the plot of P versus dn and the value is found to be 1.30 kgm-1 . Since the material takes some time to revert to elastic mode, for every indentation a correction x is applied to the d value and the Kickâ&#x20AC;&#x2122;s law is related as P=K2(d+x)2, and the value of K2 is 34.67 kgm-1. For the grown crystals, the plot dn/2 versus d gives Â˝

slope (K2 ) , the intercept is a measure of x and it is found to be -0.82. The fracture toughness (K c ) 1

is given by đ?&#x2018;&#x192;

Kc =đ?&#x203A;˝ đ??ś 3/2

(9)

where P is the applied load and the geometrical constant and the value is equal to 7 for Vickers indenter and the value of Kc is 0.5829 MN m-3/2. The another property which affects the mechanical behavior is Brittleness index ( Bi ) which is equal to 736 m-1/2, calculated using đ??ť

Bi =đ??žđ?&#x2018;Ł

(10)

đ?&#x2018;?

The yield strength (Ď&#x192;v ) of the material was found to be 469.86 MPa, determined using Eq.11 and the first order elastic stiffness coefficient C11 is 2.88Ă&#x2014; 1014 Pa derived using Wooster's empirical relation Eq.12. 12.5(đ?&#x2018;&#x203A;â&#x2C6;&#x2019;2) đ?&#x2018;&#x203A;â&#x2C6;&#x2019;2

đ??ť

đ?&#x153;&#x17D;đ?&#x2018;Ł = 2.9đ?&#x2018;Ł {1 â&#x2C6;&#x2019; (đ?&#x2018;&#x203A; â&#x2C6;&#x2019; 2)} [ 1â&#x2C6;&#x2019;(đ?&#x2018;&#x203A;â&#x2C6;&#x2019;2) ]

(11)

đ??ś11 = (đ??ťđ?&#x2018;Ł )4 MMSE Journal. Open Access www.mmse.xyz

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AC and DC Conductivity. 0.0010

50Hz 200Hz 300Hz 700Hz 900Hz 1000Hz 2000Hz 3000Hz 4000Hz

0.00040 0.00035

ď łac conductivity

0.0008

313 K 333 K 363 K 393 K

0.0006

0.0004

0.0002

0.00030 0.00025 0.00020 0.00015 0.00010 0.00005

0.0000

0.00000 1

320

340

360

380

400

Temperature (K)

log F

Fig. 5. Plot of Ď&#x192;ac conductivity with log (f)

Fig. 6. Plot of Ď&#x192;ac conductivity with temperature.

The AC conductivity of SHS, Ď&#x192;ac is calculated by substituting the values of đ?&#x153;&#x2013; â&#x20AC;˛ and tanÎ´ in the formula Ď&#x192;ac=2Ď&#x20AC;fđ?&#x153;&#x2013;0 đ?&#x153;&#x2013; â&#x20AC;˛ tanÎ´, where f is the frequency in Hertz. Fig.5 shows Ď&#x192;ac with respect to log F. From Fig.5 it is observed that SHS crystal has very low conductivity in the low frequency region upto the frequency 50 Hz to 10 KHz for all temperatures. At 100 KHz, the conductivity increases abruptly for all the measured temperatures, indicates the dielectric breakdown frequency. Fig.6, Ď&#x192;ac with respect to temperature, shows that the value of Ď&#x192;ac found to increase with the increase in frequency. The activation energy đ??¸đ?&#x2018;&#x17D; is calculated from the plot between log Ď&#x192;ac and the inverse of temperature using đ??¸ the relation [6] Ď&#x192;=đ?&#x153;&#x17D;0 đ?&#x2018;&#x2019;đ?&#x2018;Ľđ?&#x2018;? (đ??žđ?&#x2018;&#x2021;đ?&#x2018;&#x17D; ) where Ď&#x192; is the conductivity and K is the Boltzmann constant and activation energy at different frequency is listed in Table 1. The DC conductivity of SHS crystal is evaluated using the relation đ?&#x153;&#x17D;đ?&#x2018;&#x2018;đ?&#x2018;? =

đ?&#x2018;&#x2018; đ??´đ?&#x2018;&#x2026;đ?&#x2018;&#x2018;đ?&#x2018;?

, where, đ?&#x2018;&#x2026;đ?&#x2018;&#x2018;đ?&#x2018;? is the total

electrical resistance, A is the area of cross section and d is the thickness of the crystal. The value of đ?&#x2018;&#x2026;đ?&#x2018;&#x2018;đ?&#x2018;? is evaluated from the Cole-Cole plot which is plotted between đ?&#x2018;? â&#x20AC;˛ =ZcosĎ´ (real part of impedance) and đ?&#x2018;? " =ZsinĎ´ (imaginary part of impedance). The Cole-Cole plots between the complex impedances of SHS crystal at various temperatures ranging from 313 K to 393 K were plotted. From the plots the bulk resistance đ?&#x2018;&#x2026;đ?&#x2018;&#x2018;đ?&#x2018;? values were measured, the bulk resistance decreases with increasing temperature resulting in the enhancement of electrical conductivity at high temperature. The activation energy (Ea) is obtained from the plot (Fig. 7) between logĎ&#x192;dcT (mho cm-1 K) and 1000/T (K-1) and the value is found to be 0.31223 eV, which is less than 0.5 eV thereby concluding that the material possesses ionic conductivity [6]. Table 1. Activation energy đ??¸đ?&#x2018;&#x17D; Ea (ev)

Freq

0.385

50 Hz

0.268

300 Hz

0.184

1MHz

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-15.5

-1

logdcT(mho cm K)

-16.0

-16.5

Ea=0.31223 eV

-17.0

-17.5

-18.0 2.5

2.6

2.7

2.8

2.9

3.0

3.1

3.2

-1

1000/T (K )

Fig. 7. Plot of logσdc versus 1000/T. Summary. Sodium hydrogen succinate, a third order nonlinear optical material was successfully grown by slow evaporation technique at room temperature. The lattice parameters, space group of the grown crystal determined by single XRD well agreed with reported results. ICP-OES analysis revealed the presence of sodium in SHS crystal. The presence of proton environment and carbon environment were confirmed by NMR studies. The optical properties of SHS crystal proves that it can be exploited for optoelectronic and photonic applications. The mechanical properties and AC and DC conductivity shows that SHS crystal can be utilized for fabricating electro-optic devices. References [1] P. S. Latha Mageshwari, R. Priya, S. Krishnan, V. Joseph, S. Jerome Das, Optics and Laser Technology 85 (2016) 66-74. [2] X. Wang, Du Y, Ding S, Wang Q, Xiang G, Xie M, Shen X, Pang D, J. Phys. Chem. B 110 (2006) 1566. [3] P. S. Latha Mageshwari, R. Priya, S. Krishnan, V. Joseph, S. Jerome Das, J Therm Anal Calorm. (2016) 1-9. [4] N. Sinha, S. Bhandari, H. Yadav, G. Ray, S. Godara, N. Tyagi, B. Kumar, Cryst.Eng.Comm 17(30) (2015) 5757-5767. [5] J. Dalal, N. Sinha, B. Kumar, Optical Materials 37 (2014) 457 - 463. [6] B. Uma, K. Sakthi Murugesan, S. Krishnan, R. Jayavel, B. Milton Boaz, Materials Chemistry and Physics 142 (2013) 659-666. Cite the paper P.S. Latha Mageshwari, R. Priya, R. Subhashini, V. Joseph, S. Jerome Das (2017). Theoretical Investigation of Optical and Mechanical Properties of Sodium Hydrogen Succinate Single Crystal: a Third Order NLO Material. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.39.34.912

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Crystal Structure, Dielectric Response and Thermal Analysis of Ammonium Pentaborate (APB)32 Hiral Raval1,2, a, Mitesh Solanki1, Bharat Parekh1, M.J. Joshi3 1 – School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, India 2 – LD College of Engineering, Navrangpura, Ahmedabad 380015, India 3 – Department of Physics, Saurasthtra University, Rajkot, India a – hiralshahraval@gmail.com DOI 10.2412/mmse.49.16.644 provided by Seo4U.link

Keywords: crystal growth, borates, slow evaporation, XRD analysis, FTIR, thermal and dielectric properties.

ABSTRACT. Nonlinear optical material Ammonium Pentaborate (APB) crystals have been grown using slow evaporation method from aqueous solution. From Powder XRD analysis the orthohrombic crystal structure was found. Various vibrations in FTIR spectrum were assigned. Thermo gravimetric analysis suggested that the crystal remained stable up to 173℃ and then decomposed through various stages and endothermic reactions were identified by DTA. The variation of dielectric constant, dielectric loss and ac conductivity with frequencies was studied at room temperature. Further investigation of dielectric properties with higher temperature is under progress.

Introduction. Borate crystals have received much attention because of their excellent physical and chemical properties. Alkali borate crystals generally possess chemical stability as well as wide range of optical transparency extended into the ultraviolet due to large difference in the electro negativities of B and O atoms [1]. For majority of borates, it is necessary to use complex and long lasting high temperature solution top-seeding methods [2]. In the current study, authors have employed inexpensive and relatively simple slow solvent evaporation method to grow ammonium pentaborate (APB) crystals. The grown crystals were characterized by Powder XRD, FTIR, thermal and dielectric analysis. Experimental. Commercially available, 32 gm ammonium pentaborate octahydrate powder (AR grade) was dissolved in 200 ml distilled water at 500C and stirred well and solvent was allowed to evaporate. By using Whatmann filter paper the grown crystals were recovered. This process was repeated three times in order to increase purity of compound. This recovered crystalline material was dissolved in 200 ml distilled water and poured in a glass beaker, which was covered with porous sheet of polymer material to allow controlled evaporation. Within a period of 35 days, prismatic, colourless and transparent crystals were grown. The crystal of maximum size 15mm x 13mm x 9mm was grown as shown in fig.1. Powder XRD of APB crystal has been carried out using Pan Analytical system with Cu Kα radiation (λ = 1.5405Å). The data were analyzed by software Powder X. The FTIR spectrum has been recorded at 300K on Bruker setup in the range of 450 to 4000 cm-1 with Attenuated Total Reflectance (ATR) technique. The thermal analysis was performed using Linseis STA- PT1600 set up in atmosphere of air at heating rate of 10K/min. The initial mass of the material subjected to the analysis was 22.6 mg. The dielectric study was carried out on pelletized APB using Agilent Technologies E4980A LCR meter in the frequency range from 20 Hz to 2 MHz at room temperature. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Fig. 1. Crystals of Ammonium Pentaborate (APB). Result and discussion

XRD Analysis Fig. 2. Powder X-ray diffraction of APB. Fig.2 shows the powder XRD pattern and the cell parameters are calculated using the software powder X, which are found to be a= 11.325 Å, b= 11.066 Å , c = 9.320Å and cell volume 1167 Å3 . This suggests orthorhombic structure of APB crystal. The APB crystal structure belongs to noncentrosymmetric space group Aba2 [4]. The data of present work are in good agreement with the reported work [3, 4]. FTIR Studies. The FT-IR spectrum of APB is presented in Fig.2. Various absorptions and corresponding assignments are summarized in Table 1. A broad envelope of comparatively less absorption between 2850 cm-1 and 3750 cm-1 corresponds to the O-H stretching of BO-H, water between and outside the lattice and NH stretching of NH4+ ion. The similar peaks with higher absorption are reported by others where KBr is taken as reference for FTIR, which contains higher absorption of O-H due to K+ ions. The NH4 symmetric stretching is observed at 1327 cm-1. The very strong absorption peak at 1021cm- 1 is attributed to B-O terminal symmetric stretching. The other assignments are summarized in Table 1.

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Fig. 3. FT-IR Spectrum of APB. Table 1. Band Assignment of APB. Band Assignment

Absorptions (in cm-1)

Band Assignment

Absorptions (in cm-1)

O-H symmetric stretching

3370

B-O ring stretching

912

NH4 symmetric stretching

1327

B-O ring stretching

779

CH2 Torsion

1237

O-B-O ring asymmetric 689 stretching

B-O terminal asymmetric 1092 stretching

O-B-O ring bending

506

B-O terminal asymmetric 1021 stretching

O-B-O ring bending

454

Thermal Analysis. Complete decomposition of Ammonium pentaborate octahydrate in form of stochiometric expression can be given as : (NH4)2O•5B2O3•8H2O

5B2O3+2NH3+9H2O

From analysis, three major stages [5] can be assigned to thermal decomposition of Ammonium Pentaborate octahydrate are as follows: (i) Dehydration: Three endothermic peaks are observed in relevance to three stages of dehydration from 71.2℃ to 110℃; 114℃ to 142℃ and 173.7℃ to 241.7℃, which corresponds to release of, total seven crystal water molecules. (ii) Decomposition: The endothermic peak observed between 285.1℃ to 332.5℃ corresponds to release of two water molecules as molecular water that was difficult to remove during dehydration. (iii) Deammination: during this stage, two molecules of NH3 are released between 428.3℃ to 458.4℃ and finally APB is transformed into five molecules of boric oxide. TGA Curve (fig. 4) and DTA curve (fig. 5) shows good agreement with each other. Comparison of observed mass loss with calculated mass loss corresponds to these stages is given in Table 2. MMSE Journal. Open Access www.mmse.xyz

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Fig. 4. TGA graph of APB. Table 2. Thermal decomposition stages of APB.

Phase

Temp. (â&#x201E;&#x192;)

Experimentall y observed Mass Loss (wt%)

Theoretically obtained Mass Loss (wt%)

Dehydration

up to 242

22.15

23.10

Decomposition

295 to 332

29.96

29.80

Deammination

428 to 458

42.77

36.05

Fig. 5. DTA trace of APB.

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Remark Loss of Seven water molecules. Loss of two water molecules which can only be removed by decomposition. Removal of two NH3 molecules.

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Dielectric analysis:

Fig. 6. (a) Dielectric constant vs. log f (b) Dielectric loss vs. log f (c) Joncher’s plot. Figs. 6 (a) and (b) show variation of dielectric constant and dielectric loss with frequency. High dielectric constant at lower frequency may be attributed to the contribution of all types of polarisation like electronic, ionic, orientational and space charge [6]. As frequency increases polarisation decreases since dipoles are unable to comply with variation of alternating field. Dielectric loss shows the similar behaviour. Fig. 6(c) indicates high frequency dispersion curve. The Joncher’s power law is σtot =σdc+Aωn where A indicates strength of polarisibility and is dependent on temperature, n is degree of interaction of mobile ions with lattice. From Fig. 6 (c) the values of parameters A and n for joncher’s equation , are obtained as 2.421X10 10 and 0.574, respectively. The AC conductivity increases with increment in frequency.Stella Mary et al [7] suggested polaron hopping mechanism for high conduction at higher frequencies. Analysis of dielectric properties including Joncher’s plot with various temperature range is under progress.

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Summary. Ammonium Pentaborate (APB) crystals were grown successfully using slow solvent evaporation technique. The Powder XRD pattern indicated orthorohmbic crystal structure. The FTIR spectrum confirmed the presence of various functional groups. The TGA suggested the APB thermally remained stable up to 173 0C and then decomposed through various stages. Nine water molecules were found to be associated with the crystal. The dielectric study indicated decrement of dielectric constant and dielectric loss as increment in frequency. Joncher’s plot suggested that AC conductivity increased with frequency. Acknowledgments. The authors are thankful to the authorities of PDPU, Prof. Nirendra Misra, (Head of Science department - PDPU), Department of Physics - Gujarat University and Prof. H. H. Joshi (HOD, Department of Physics - Saurashtra University) for their keen interest and valuable support. The author is thankful to A. P. Kochuparampil , J.H. Joshi and Chandra Kanth P. for their help in data analysis. References [1] C. Chen, Y. Wu, R.Li, J. Crystal Growth 99 (1990), 790. [2] V.T. Adamiv, Y. V. Burak, J.M. Teslyuk, J. Cryst. Growth, 289(2006) 157. [3] W. R. Cook, Hans Jaffe, Acta. Cryst. (1957), 10, 705. [4] Becker, P., Held, P., Bohatý, L.: Crystal Growth and Optical Properties of the Polar Hydrated Pentaborates Rb [B5O6(OH4)]× 2H2O and NH4 [B5O6(OH4)]× 2H2O and Structure Redetermination of the Ammonium Compound. Cryst. Res. Technol. 35 (2000), 1251 [5] Omer Sahin et al, Ind. Eng. Chem. Res., Vol. 40, No.6, (2001), 1465-1470. [6] J.H. Joshi, K.P. Dixit, M.J. Joshi and K.D. Parikh, Study on A.C. electrical properties of pure and L-serine doped ADP crystals, AIP Conf. Proceedings 1728, 020219 (2016), DOI: 10.1063/1.4946270 [7] S. Stella Mary et al, Growth and Characterization of Sodium Pentaborate [Na(H4B5O10)] Single Crystals Spectrochimica, Acta A: Mol. And Biomol. Spectro. 71 (2008) 10, DOI: 10.1016/j.saa.2008.04.021 Cite the paper Hiral Raval, Mitesh Solanki, Bharat Parekh, M.J. Joshi (2017) Crystal Structure, Dielectric Response and Thermal analysis of Ammonium Pentaborate (APB). Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.49.16.644

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Investigation on Thermal, Optical, Second Order and Third Order NLO Properties of a Nonlinear Optical Single Crystal of L-Leucinium Hydrogen Maleate (LLM)33 Hemalatha1,2, S. Senthil2, a 1 – Department of Physics, Quaid-E-Millath Government College for women, Chennai – 02, Tamil Nadu, India 2 – Department of Physics, Government Arts College (Men), Nandanam, Chennai-35, Tamil Nadu, india a – ssatoms@yahoo.co.in DOI 10.2412/mmse.1.75.798 provided by Seo4U.link

Keywords: XRD studies, TGA – DTA, NLO efficiency, absorption spectral analysis, Z-Scan studies.

ABSTRACT. Organic Nonlinear optical (NLO) single crystals of L--Leucinium Hydrogen Maleate (LLM) have been grown by the slow evaporation solution growth technique at room temperature. The X-Ray diffraction studies proved that the LLM crystals belong to monoclinic system with noncentrosymmetric space group (C2). The decomposition and thermal strength of the LLM crystals were established by TGA/DTA studies. UV-vis-NIR absorption study shows good transparency of the LLM crystal and the lower cut-off wavelength was found to be 212 nm. The optical band gap, reflectance, refractive index and electrical susceptibility were also calculated. Second order efficiency of the LLM crystal was determined using Kurtz and Perry powder technique. Third order nonlinear studies were performed using Z-Scan technique. Nonlinear parameters such as nonlinear refractive index, absorption coefficient, and nonlinear optical susceptibility were evaluated for the LLM crystal.

Introduction. Amino acid is one of the rich choice for NLO material because of its coherent blue green laser generation and frequency doubling applications. Amino acids are promissing candidate for its chirality, weak vanderwaals and hydrogen bonds, the absence of strongly conjugated bonds, wide transparency, bands in the visible and UV spectral regions and zwitter ionic nature of the molecule which is important for crystal hardness [1]. In the crystal engineering and supramolecular point of views L-Leucine is an interesting molecule compared to other amino acid materials and it is an essential branched chain of alpha amino acid [2]. Many optically active aminoacids show highly efficient second harmonic generation. Maleic acid forms crystalline maleate of various organic molecules through hydrogen bonding and π- π interactions. In maleic acid the intramolecular hydrogen bond is very strong and has large π-conjugation has attracted our attention [3]. In this paper, it is reported on growth of L-Leucinium Hydrogen Maleate (LLM) single crystal followed by characterizations like XRD, TG-DTA, UV-Vis-NIR and NLO studies are discussed in detail. Experimental procedure. A supersaturated solution of L-Leucinium Hydrogen Maleate was prepared using L-Leucine and L-Malic acid in equimolar proportion. The solution was stirred continuously using a magnetic stirrer for 5 hrs. The prepared solution was fitted and kept undisturbed for crystalisation at room temperature. Finally, after 35 days well defined single crystals were obtained by slow evaporation solution growth method. The photograph of the grown crystal of L Leucinium Hydrogen Maleate is shown in fig.1 Results and discussion X-ray diffraction studies. The powder x-ray diffractrometry (XRD) analysis was performed with CuK radiation. The title compound was crystallizes in monoclinic system with noncentro symmetric © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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space group of C2 and with lattice parameters a=21.132 AË&#x161;, b=5.226 AË&#x161;, c=31.452 AË&#x161;, Î˛=98.439Â°. These values were found to be in good agreement with the reported values [4]. The recorded powder x-ray diffraction pattern of LLM sample is shown in fig.2. The sharp peak and well defined Braggâ&#x20AC;&#x2122;s peaks at specific 2ď ą angles shows good crystallinity of the material. Thermo gravimetric Analysis. Thermal analysis was performed on the powder sample of grown crystal to study the thermal stability and decomposition. The thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) curves of LLM were obtained in the range between room temperature (28Ë&#x161;C) and 700Ë&#x161;C at a heating rate of 10Ë&#x161;C per min. The experiment was performed in nitrogen atmosphere. From the TGA curves (Fig.3), it is observed that there is no weight loss upto 142Ë&#x161;C and there is a single stage of weight loss between 142Ë&#x161;C and 574Ë&#x161;C. One exothermic peak at 142Ë&#x161;C and two endothermic peaks are observed at 478Ë&#x161;C and 544Ë&#x161;C. The DTA replicate exactly the same change at 142Ë&#x161;C by the TG curve. From this the thermogravimetric analysis shows that the material has very good thermal stability up to 142Ë&#x161;C [5]. The sharpness of the peak ensures the purity and good crystallinity of the material.

(3 1 -4)

(4 0 3) (4 0 4)

(0 0 6) (2 0 -6) (4 0 -4)

(4 0 -1)

(2 0 3)

100

(2 0 4) (2 0-5)

Intensity(CPS)

150

10 10

LLM 8

(3 1 -7)

(1 1 6) (2 0 8)

200

0 0

2 Theta(degrees)

Fig. 1. Photograph of as grown single crystal.

142Â°C

Fig. 2. Powder XRD pattern of the LLM crystals.

7000

LLM

478Â°C 554Â°C

6000 5000

4000

3000

DTA% min

2000

DTA

1000

-20

574Â°C

-40

142Â°C 0

100

200

300

400

500

600

0 -1000 700

TEMP (Â°C)

Fig. 3. TG/DTA curve for LLM crystal. Optical Studies. UV visible spectra are recorded between 200 nm and 1100 nm and is shown in fig.4 (a). The lower cutoff wavelength was found to be around 212nm. The crystals are highly transparent in the entire visible region and it is essential quality for optically active material. Hence the crystals are useful for optoelectronic applications. The recorded optical data was used to calculated band gap of the grown crystal. The absorption coefficient (ď Ą) of the LLM crystal was calculated by the relation [6] ď Ą= Absorption/đ?&#x2018;Ą where â&#x20AC;&#x2DC;tâ&#x20AC;&#x2122; is the thickness of the sample. The optical band gap has been evaluated from the relation [6] MMSE Journal. Open Access www.mmse.xyz

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(ď Ąhď Ž)2=A(Eg-hď Ž)

(1)

Where A is a constant, Eg is the optical band gap, h is the Plankâ&#x20AC;&#x2122;s constant and ď Ž is the frequency of incident photons. The optical band gap was evaluated by plotting (ď Ąhď Ž)2 Vs hď Ž is as shown in fig.4(b). and the band gap value is found to be 5.42 eV. The extinction coefficient (k) is calculated using the following relation K=ď Źď Ą/4ď °. The linear refractive index to energy band gap relation is given by Egen = 36.3. The Reflectance value is evaluated from the refractive index (n) [7] is given by

2.4

212

(ď Ąhď ľ ď&#x20AC;˛x105(eV)2m-2

2.2 2.0 1.8 1.6 1.4

ď&#x20AC;Š

Asorption (A) (%)

LLM

1.2

6 5 4 3 2 1 0

1.0

5.42eV

-1

200 300 400 500 600 700 800 900 1000 Wavelength (ď Źď&#x20AC;Šď&#x20AC; nm

hď ľď&#x20AC; eVď&#x20AC;

Fig. 4. (a) UV-Vis absorption spectrum of LLM. Fig. 4. (b) Plot of (ÎąhÎ˝)2 versus hÎ˝ of LLM. đ?&#x2018;&#x203A;â&#x2C6;&#x2019;1

R= (đ?&#x2018;&#x203A;+1)2

(2)

The dielectric constant is given by ď Ľc=ď Ľr+ď Ľi where ď Ľr=n2-K2=n2-1 and ď Ľi=2nk, here ď Ľr and ď Ľi are real and imaginary part of the dielectric constant. The Electrical susceptibility (ď Łe) was evaluated using the following relation [7] (ď Łe) = ď Ľr-1 = n2-1. The extinction coefficient, linear refractive Index, Reflectance and Electrical Susceptibility of the LLM crystals are 7.8953x10 -5, 2.0336, 0.116 and 3.1355 respectively. Second order NLO Properties. Kurtz and Perry technique was employed to estimate the Second harmonic generation (SHG) efficiency of the grown sample. A high intensity Nd:YAG laser (ď Ź=1064nm) with pulse duration of 8 ns a repetition rate of 10Hz was passed through the powdered sample. The incident input energy of 0.7J/s was incident on the crystalline powder and the output signal of 2.98 mW obtained from LLM crystal which was confirmed by green emission (532nm) of the laser beam. It is observed that the SHG efficiency of the grown single crystal is 0.6 times that of the standard KDP crystal (5.03mW). Third order NLO Properties. The single beam z scan technique is developed by Mansour Sheik Bahae [8] and it is a popular and very accurate method to determine the NLO parameters of the refractive index (n2), nonlinear absorption coefficient (Î˛) and nonlinear susceptibility (ď Ł(3))of the grown LLM crystal. Z scan technique play a important role in the development of photonic device for all optical signal processing. In this method, the sample was translated across the +z to â&#x20AC;&#x201C;z axial direction along a focussed Gaussian laser beam of wavelength 632.8 nm (He-Ne laser) by using stopper motor to vary the incident intensity falling on the sample. The source light is focused by a lens of focal length 22.5 cm and intensity variation of the transmittance are measured by using digital meter through closed aperture. The recorded results of normalized transmittance measurement for the MMSE Journal. Open Access www.mmse.xyz

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16.5

Normalized Transmittance ( a.u.)

LLM crystal of open and closed aperture curves are given in fig. 5(a) and 5(b). In closed aperture curve, the prefocal to post focal peak configuration has the positive third order nonlinear refractive index. This behaviour can be assigned to self focusing effect due to large beam divergence and reduced transmittance through the far field aperture. This is a necessary property for optical switching application.

LLM

16.0 15.5 15.0 14.5 14.0 13.5 13.0 6

14.5

LLM

14.0 13.5 13.0 12.5 12.0 11.5 10

Z (mm)

Fig. 5. (a) and (b) open and Closed aperture z-scan spectrum of LLM crystal. From the z scan data curves the difference between the valley and peak transmittances (ď &#x201E;Tv-p) is written in terms of the on-axis phase shift at the focus (ď &#x201E;ď &#x2020;o) as [9],

ď &#x201E;Tv-p= 0.406(1-S)0.25|ď &#x201E;ď &#x2020;đ?&#x2018;&#x153;|

(3)

where S is the linear aperture transmittance and is given by [9] the equation S =1-exp [-2ra2/Ď&#x2030;a2] where ra is the radius of the aperture and ď ˇa is the beam radius at the aperture. The nonlinear refractive index (n2) was calculated using closed aperture z scan data and it is given by the simple expression [9] ď &#x201E;ď &#x2020;đ?&#x2018;&#x153;

n2= đ?&#x2018;&#x2DC;đ??ź

0 đ??żđ?&#x2018;&#x2019;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C;

(4)

where k is the wavenumber (k=2ď °/ď Ź), Io is the intensity of the laser beam at the focus (z=0) and the effective thickness of the sample is calculated using formula [9] Leff=[1-exp(-ď ĄL)/ ď Ą

(5)

where ď Ą the linear absorption and L is is the thickness of the LLM crystal. From the open aperture curve nonlinear optical absorption coefficient (Î˛) was estimated from the relation [9] 2â&#x2C6;&#x161;2ď &#x201E;đ?&#x2018;&#x2021;

Î&#x2019;=đ??ź

0đ??żđ?&#x2018;&#x2019;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C;

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(6)

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where ď &#x201E;T is the valley point at the open aperture z scan curve. The real and imaginary parts of the third order nonlinear optical susceptibility ( ď Ł(3)) were enumerated using the equation [9] Reď Ł(3)(e.s.u.)=

10â&#x2C6;&#x2019;4(ď Ľ0 đ?&#x2018;? 2 đ?&#x2018;&#x203A;0 2đ?&#x2018;&#x203A; 2 )

Imď Ł(3)(e.s.u.)=

ď °

cm2/W

10â&#x2C6;&#x2019;2(ď Ľ0 đ?&#x2018;? 2 đ?&#x2018;&#x203A;02 ď Źđ?&#x203A;˝) 4ď °

(7)

cm2/W.

(8)

whereÎľo is the vacuum permittivity and c is the velocity of light in vacuum, no is the refractive index of the sample, Îť is the wavelength of the He-Ne laser beam. The third order nonlinear optical susceptibility was calculated using the relation [9], ď Ł(3) = â&#x2C6;&#x161;(Reď Ł(3) )2 + (Imď Ł(3) )2

(9)

Real susceptibility is directly proportional to the Index of refraction and the imaginary susceptibility is directly proportional to the nonlinear absorption coefficient. The obtained z scan parameters of LIM crystals are shown in table 1. Table 1. Parameters measured in z scan technique for LLM crystals. 1

Effective thickness (Leff)

4.834

Nonlinear refractive index (n2)

4.26479x10-11 cm2/W

linear absorption coefficient (ď Ą)

0.13377

Nonlinear absorption coefficient (Î˛)

2.467x10-5 cm/W

Third order nonlinear susceptibility (ď Ł(3))

19.18x 10-8 esu

Third order nonlinear susceptibility (ď Ł(3))

5.58986x10-5 esu

Third order nonlinear susceptibility (ď Ł(3))

0.191x10-5 esu

Summary. The L-Leucinium Hydrogen Maleate single crystals were grown by slow evaporation technique. From the X-ray diffraction, it was confirmed that the crystal belongs to monoclinic structure with noncentrosymmetric space group C2. Thermal studies indicate that the LLM is suitable for possible applications upto142Ë&#x161;C. Optical transparency of the crystals was observed by UV-Vis specral analysis. The band gap, refractive index, reflectance, extinction coefficient and electrical susceptibility were calculated for the UV cut off wave length 212nm. The nonlinear optical property of the grown crystal was found by second order Kurtz Perry powder technique. The third order nonlinear refractive index, absorption coefficient and susceptibility were determined by the Z-scan technique. And it is suitable for NOL applications. From this investigation, it is observed that the grown crystals are useful in nonlinear optoelectronic device applications. References [1] S. Senthil, S.Pari, P.Sagayaraj, J.Madhavan, Studies on the electrical, linear and nonlinear optical properties of Meta nitroaniline, an efficient NLO crystal, Journal of Physica B, 2009,404, 1655â&#x20AC;&#x201C;1660, doi:10.1016/j.physb.2009.01.042

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[2] P. Baskarana, M. Vimalanb, P. Anandand, G. Bakiyarajc, K. Kirubavathia,K. Selvarajua, Synthesis, growth and characterization of a nonlinear optical crystal:l-Leucinium perchlorate, Journal of Taibah University for Science , 2016, doi.10.1016/j.jtusci.2016.03.003. [3] C. Alosious Gonsago, Helen Merina Albert, S. Janarthanan, and A. Joseph Arul Pragasam. Crystal Growth and Characterization of an Organic Nonlinear Optical Material: L-Histidinium Maleate (LHM), International Journal of Applied Physics and Mathematics, 2012,Vol. 2, No. 6, doi: 10.7763/IJAPM.2012.V2.150. [4] Sergey G. Arkhipov, Denis A. Rychkov, Alexey M. Pugachevc and Elena V.Boldyrevaa, Structural Chemistry(Research Paper), New hydrophobic L-amino acid salts: maleates of L-leucine, L-isoleucine and L-norvaline, Journal of Acta Crystal C, 2015, C17, 1-9. doi. 10.1107/S2053229615010888. [5] Adhikari.S, Kar. T., Experimental and theoretical studies on physicochemical properties of Lleucine nitrate a probable nonlinear optical material Journal of Cryst. Growth, (2012), 356, 4-9, doi.10.1016/j.jcrysgro.2012.07.008. [6] Mohd Shkir, Haider Abbas, Physico chemical properties of L-asparagine L-tartaric acid single crystals: A new nonlinear optical material, Journal of Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014, 118, 172–176, doi.10.1016/j.saa.2013.08.086. [7] D.Shanthia, P. Selvarajana and S. Perumalb, Growth, spectral, third order NLO and impedance analysis of L-alaninium maleate crystals admixtured with urea, Journal of Materials Today: Proceedings, 2015, 2, 943 – 948, doi.10.1016/j.matpr.2015.06.013. [8] Adeleh Granmayeh Rad, Single Beam Z-Scan Measurement of Nonlinear Refractive Index of Crude Oils, Journal of Modern Physics, 2014, 5, 280-284, doi.10.4236/jmp.2014.55038 [9] K. Thirupugalmani, S. Karthick, G. Shanmugam, V. Kannan, B. Sridhar, K. Nehru, S. Brahadeeswaran, Second- and third-order nonlinear optical and quantum chemical studies on 2amino-4-picolinium-nitrophenolate-nitrophenol: A phasematchable organic single crystal Optical Materials 49 (2015) 158–170, doi.10.1016/j.optmat.2015.09.014. Cite the paper Hemalatha, S. Senthil (2017). Investigation on Thermal, Optical, Second Order and Third Order NLO Properties of a Nonlinear Optical Single Crystal of L-Leucinium Hydrogen Maleate (LLM). Mechanics, Materials Science & Engineering, Vol 9. 10.2412/mmse.1.75.798

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Growth and Dielectric Properties of 1,3-bis(4-methoxyphenyl)prop-2-en-1-one Organic Single Crystal34 K. Arunkumar1, S. Kalainathan 1,a 1 – Centre for Crystal Growth, VIT University, Vellore 632014, India a – kalainathan@yahoo.com DOI 10.2412/mmse.12.10.956 provided by Seo4U.link

Keywords: crystal growth, organic material, dielectric properties, powder XRD.

ABSTRACT. High-quality single crystal of 1,3-bis(4-methoxyphenyl)prop-2-en-1-one (BMP) has been grown by the vertical Bridgman technique. Calculated the grain size of BMP single crystal from powder XRD. 1H NMR spectrum was recorded to confirm the presence of protons in the synthesized compound. The dielectric constant and dielectric loss of the grown crystal was studied as a function of frequency with different temperatures and the results are discussed.

Introduction. In the past few years, optoelectronic materials have prompted researchers to grow large size of organic single crystals for advanced high technology devices. NLO has emerging as one of the most attractive field of research in view of vital applications such as high speed information processing, optical data storage, optical communications and frequency conversion [1, 2]. The high dipole moment generally leads to the molecules packing in centrosymmetric arrangements and SHG responses in these systems become zero. Therefore, one requires a highly hyperpolarizable molecule aligned in a head-to-tail fashion, connected through strong hydrogen bond interactions, crystallizing in noncentrosymmetric structures and produce high second harmonic generation efficiency. Chalcones are interesting organic NLO materials that show good crystallizability, high SHG conversion efficiency compared to urea [3, 4]. In recent years, researchers focused on the growth of high quality organic single crystals. The organic single crystals can be grown by different techniques. In certain organic materials, the solution growth techniques such as slow cooling and slow evaporation take more time to crystallize and difficult to grow large size crystals and sometimes the solvent inclusion can reduce the optical property of the crystal [5]. The melt growth technique is one of the techniques widely used to grow organic and inorganic single crystals. Bridgman technique is the simplest and best technique for the growth of large size good quality transparent crystals from melt in the stipulated period [6]. This paper, deals with the growth of 1,3-bis(4-methoxyphenyl)prop2-en-1-one (BMP) by two zone vertical Bridgman technique and its rest of the characterizations 1H NMR and Dielectric properties. Experiment. In the present experiment, the synthesized and purified raw material of BMP was charged into the single wall conical shaped borosil glass ampoule [4]. In the ampoule cone length was increases the crystal quality increases [7], and then ampoule admitted to high vacuum (10 -6 Torr) and carefully sealed off. The upper zone temperature was maintained at 3°C above the melting point [4]. The furnace temperature profile is shown in Fig.1a. The ampoule was allowed to stand for 8 h in upper zone to maintain thermal equilibrium and to avoid bubble formation of during crystal growth. The translation of the melted substance from upper zone to the lower zone very slowly. Because the organic materials have low thermal conductivity takes more time to solidify from the melt [5]. In the present study, we tried three translations rate (1.0, 0.5 and 0.3mm). First two translation were occurred © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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multi- nucleation finally we optimized the third translation rate was 0.3mm/ hr got the good transparent BMP single crystal. After growth has been completed, the heating profile was reduced step by step to room temperature at a rate of 1 to 3°C/hr. In order to avoid cracks due to the difference in the thermal expansion coefficient between the borosil glass and crystal. The grown crystal was removed from the single wall ampoule carefully by using the standard diamond wheel cutter. The good transparent BMP single crystal with, cut and polished crystal is shown in Fig.1b.

Fig. 1. (a) Temperature profile, (b) grown BMP single crystal. Result and discussion. From single crystal X-ray diffraction analysis the lattice parameter were determined. The crystal belongs to be orthorhombic crystal system and the unit cell was determined as a = 5.332Å, b = 8.730Å, c = 30.931Å which is in good accordance with that of the reported value [4]. The indexed powder X- ray diffraction pattern of the BMP single crystal is shown in Fig. 2.

Fig. 2. (a) Powder X- ray diffraction (b) BMP single crystal and (C) Expand the single crystal peak.

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3.1 Determination of Grain size from Powder XRD spectra. From the powder XRD pattern, it is observed that, the grain size is determined by measuring the width of the line with highest intensity peak in crystal using powder X software. From the powder XRD pattern, it is observed that, the grain size is determined by measuring the width of the line with highest intensity peak in crystal using powder X software. The grain size can be calculated by using the formula, đ??ˇ=

0.9 đ?&#x153;&#x2020; đ?&#x203A;˝ đ??śđ?&#x2018;&#x153;đ?&#x2018; đ?&#x153;&#x192;

(1)

Where, Î˛ is full with of half maxima (FWHM) and D is grain size of the crystal. 0.9 đ?&#x2018;&#x2039; 1.54056

đ??ˇ = 0.226 đ?&#x2018;&#x2039; đ??śđ?&#x2018;&#x153;đ?&#x2018; (28.38) = 0.6973 đ?&#x2018;&#x203A;đ?&#x2018;&#x161;

(2)

NMR spectra. The 1H nuclear magnetic resonance spectrum is display in Fig. 3. The peaks absorbed at Î´= 6.914, 6.934, 6.958 and 6.978ppm are assigned to chalcone protons. The doublets at Î´= 7.752, 8.016 ppm ascribed to p-substituted phenyl ring next to the carbonyl group. The protons present in the methoxy substituted aromatic ring shows the doublets at 7.402 and 7.578ppm. The singlet peaks absorbed at 3.838ppm and 3.871ppm indicates the presence of hydrogen atoms in the â&#x20AC;&#x201C;OCH3 group. Thus the 1H NMR spectral study confirm the functional groups present in the target compound BMP and hence the molecular structure.

Fig. 3. 1H NMR spectrum of BMP. Dielectric study. The dielectric constant and dielectric loss of the grown crystal were measured at different temperatures using HIOKI 3532-50 LCR HITESTER. The crystals particularly when they are non conducting materials, therefore applied the high grade Silver paste over the sample to make uniform electrical contact with the surface of electrodes. The dielectric constant of BMP was calculated using the following relation.

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εr =

Ct , εoA

(3)

where εr is the dielectric constant, C is the capacitance of the medium, t is the thickness of the sample, εo is the absolute permittivity in free space (8.854x10-12 F/M), and A is the area of the sample. Fig.4 shows the plot of dielectric constant (εr) as a function of frequency. It is found that the dielectric constant decreases with increase in frequency for all temperatures. The high values of dielectric constant at low frequency enumerates the contribution from all four sources of polarizations are active namely electronic, ionic, atomic and space charge developed in the material due to the electric field variations. The high dielectric constant at low frequency observed for BMP crystal is due to the presence of space charge polarization arising at the grain boundary interfaces [8, 9]. The low values of dielectric constant at large frequencies revealed the good optical quality of the grown crystal with less defects, which is the desirable property of the materials to be used for various optical and communication devices. Fig. 2 shows that dielectric loss against log frequency. The low value of the dielectric loss reveals that the very high purity of the title compound. Suppose the dielectric loss value is large may be attributed to the space charge. The grown crystal low values of dielectric constant and dielectric loss with large frequencies, suggests that the sample possesses good optical quality with lesser defects [10]. Moreover this type of materials needs the microelectronics industry replacement of dielectric materials in multilevel interconnected structures with new low dielectric constant materials [11].

Fig. 4. Plot of dielectric constant versus applied frequency.

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Fig. 5. Dielectric loss as a function of frequency. Summary. It has been concluded that BMP single crystal can be grown by two zone vertical Bridgman technique. Calculated the grain size of maximum intensity peak value is 0.6973 nm. Low values of dielectric constant and dielectric loss with high frequencies, suggests that the sample possesses good optical quality and microelectronics industry replacement of low dielectric constant materials. References [1] Nirmala, L. R., & Prakash, J. T. J. (2013). Investigation on the influence of foreign metal ions in crystal growth and characterization of L-Alaninium Maleate (LAM) single crystals. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 115, 778-782.10.1016/j.saa.2013.06.100 [2] Lenin, M., & Ramasamy, P. (2008). Synthesis, growth and characterization of 3nitroacetanilide—A new organic nonlinear optical crystal by Bridgman technique. Journal of Crystal Growth, 310(20), 4451-4455.10.1016/j.jcrysgro.2008.04.055 [3] D'silva, E. D., Rao, D. N., Philip, R., Butcher, R. J., & Dharmaprakash, S. M. (2011). Synthesis, growth and characterization of novel second harmonic nonlinear chalcone crystal. Journal of Physics and Chemistry of Solids, 72(6), 824-830.10.1016/j.jpcs.2011.04.003. [4] Ravindra, H. J., Harrison, W. T. A., Kumar, M. S., & Dharmaprakash, S. M. (2009). Synthesis, crystal growth, characterization and structure–NLO property relationship in 1, 3-bis (4methoxyphenyl) prop-2-en-1-one single crystal. Journal of Crystal Growth, 311(2), 310315.10.1016/j.jcrysgro.2014.04.026 0022-0248/& 2014 [5] Suthan, T., & Rajesh, N. P. (2010). Growth and characterization of organic material 4nitrobenzaldehyde single crystal using modified vertical Bridgman technique. Journal of Crystal Growth, 312(21), 3156-3160.10.1016/j.jcrysgro.2010.08.002. [6] Babu, G. A., & Ramasamy, P. (2010). Growth and characterization of organic molecular single crystal ethyl p-amino benzoate by selective self seeding from vertical Bridgman technique. Journal of Crystal Growth, 312(16), 2423-2426.10.1016/j.jcrysgro.2010.05.012 [7] Arivazhagan, T., & Rajesh, N. P. (2014). Investigation on the growth and characterization of nonlinear optical single crystal 4, 4‫׳‬-dimethoxybenzoin by vertical Bridgman technique. Optics & Laser Technology, 64, 156-161.10.1016/j.optlastec.2014.05.014 [8] Vijayan, N., Bhagavannarayana, G., Budakoti, G. C., Kumar, B., Upadhyaya, V., & Das, S. (2008). Optical, dielectric and surface studies on solution grown benzimidazole single crystals. Materials Letters, 62(8), 1252-1254.10.1016/j.matlet.2007.08.023 MMSE Journal. Open Access www.mmse.xyz

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[9] Sowmya, N. S., Sampathkrishnan, S., Sudhahar, S., Kumar, M. K., & Kumar, R. M. (2016). Synthesis, growth, structural, optical, thermal, dielectric and mechanical studies of piperidinium pnitrophenolate single crystals. Optik-International Journal for Light and Electron Optics, 127(5), 3024-3029. 10.1016/j.ijleo.2015.12.065 [10] Yadav, H., Sinha, N., & Kumar, B. (2015). Growth and characterization of new semiorganic nonlinear optical and piezoelectric lithium sulfate monohydrate oxalate single crystals. Materials Research Bulletin, 64, 194-199.10.1021/acs.cgd.5b00792 [11] Suthan, T., Dhanaraj, P. V., Rajesh, N. P., Mahadevan, C. K., & Bhagavannarayana, G. (2011). Growth and characterization of benzil single crystals using nanotranslation by the modified vertical Bridgman technique. CrystEngComm, 13(12), 4018-4024.10.1039/c0ce00453g Cite the paper K. Arunkumar, S. Kalainathan, (2017). Growth and Dielectric Properties of 1,3-bis(4-methoxyphenyl)prop-2en-1-one Organic Single Crystal. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.12.10.956

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Effect of Hydrochloric Acid (HCl) on Synthesis and Anisotropic Phenomena of Triglycine Phosphate (TGP) Single Crystals35 M.R. Meera1,2, S.L. Rayar3, V. Bena Jothy1, a 1 – Department of Physics and Research Centre, Women’s Christian College, Nagercoil, Tamil Nadu, India 2 – Department of Physics, Sree Ayyappa College for Women, Chunkankadai, Nagercoil, Tamil Nadu, India 3 – Department of Physics, St.Judes College, Thoothoor, Tamil Nadu. India a – meeranairmrm17@gmail.com DOI 10.2412/mmse.60.6.225 provided by Seo4U.link

Keywords: TGP; NLO; PXRD: FTIR; EDAX; UV;TGA/DTA.

ABSTRACT. Effect of Sulphuric acid (H2SO4) addition on the growth of triglycine phosphate (TGP) crystal has been studied from the aqueous solution by slow evaporation technique. The characteristics absorption bands of pure and H2SO4 admixtured TGP crystals are confirmed by FTIR spectra. UV-visible transmittance spectra were recorded for the samples to analyze the transparency of the grown crystals. The composition of pure and doped TGP crystals have been confirmed by EDAX analysis. The dielectric constants of the crystals have been studied and result suggests that the H2SO4 is doped into TGP crystal and that the doping increases its dielectric parameters.

Introduction. Investigations on semiorganic nonlinear optical (NLO) materials gain importance because of good thermal and mechanical properties with large NLO coefficients [1,2]. Among the amino acids, glycine [amino acetic acid: NH2CH2COOH] is the simplest amino acid, hence,glycine mixed semi-organic material is a fundamental building block to grow many complex crystals with improved NLO properties. Reported literature shows that glycine sodiumnitrate [3], triglycine sulphate [4] etc. crystals exhibit of some glycine based compounds like triglycine zinc chloride [5], glycine sodium nitrate [6] and triglycine selenate [7] show non-linear effects ferroelectric properties and are used as infrared detectors, transducers and piezoelectric sensors due to the large difference between the inter-molecular and intra molecular chemical bonds [5–7]. One of the hydrogen bonded ferroelectric single crystal Glycine phosphate (GPI) undergoes a continuous ferroelectric–para electric phase transition at 224.7K [8]. Subsitutional or interstitial impurities in the host lattice leads to significant changes in the properties of the pure TGS crystals [9-10]. The pyroelectric coefficient of phosphoric acid doped TGS is more than that of pure TGS and observed phase transition temperature shift [11]. Inview of this, the present investigation has been focused on the growth of semi-organic Triglycine phosphate (TGP) single crystals doped with sulphuric acid at various concentrations (0.25,0.50,0.75 and 1.0 mol %) and this doping efforts on the growth aspects, structural perfection, phase transition temperature, and optical properties were studied by conducting various characterization techniques. Experimental Details. Triglycine phosphate was synthesized by taking the Analar grade glycine (99%) and phosphoric acid in the molar ratio of 3:1.The doped samples were prepared by mixing fixed amount of Sulphuric acid (0.25, 0.50, 0.75, and 1.0 mol%) with glycine and phosphoric acid. The Prepared solutions were then filtered and the purity of the salts was achieved by repetitive recrystallization. The filtered solution was kept in a beaker covered with porous papers and kept in a dust-free atmosphere. After a period of 15-20 days, colorless and transparent crystals were obtained. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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For the purpose of powder X-ray diffraction analysis of powdered sample of the grown crystals XPert PRO powder X-ray diffractrometer is used. Energy Dispersive X-ray analysis were carried out using a Bruker EDS spectrometer in conjunction with the SEM. FT-IR spectra of pure and doped TGP have been recorded using Bruker IFS 66 V Spectrometer in the range 4000-100 cm-1. Thermal analysis were carried out simultaneously employing Perkin Elmer thermogravimetric and differential analyser (Mode: PYRIS DIAMOND) in nitrogen atmosphere heated from 400 to 7300 with a heating rate of 100ºC to understand thermal behaviour. Results and Discussion PXRD Analysis. Single crystal XRD data of the pure TGP crystal suggests that the crystal belongs to monoclinic structure. In order to confirm the material of the grown crystal, powder XRD data were collected from the pure and hydrochloric added TGP crystals. Powder diffractogram of the pure and H2SO4 admixture TGP are shown in Fig 1. Comparing PXRD patterns of doped crystals with those of pure TGP single crystal, small changes in ‘d’ - spacing values were observed, which may be attributed to the presence of dopants in TGP crystal. It is clear that for all the grown crystals a ≠ b ≠ c which ensures that all the grown crystals is of monoclinic structure [12]. Analysis of the PXRD spectra confirmed the excess H2SO4 only acted as the additive rather than as dopant.

Fig. 1. PXRD (A) Pure TGP (B) TGP + 0.25mol % of H2SO4 (C) TGP + 0.50 mol % of H2SO4 (D) TGP + 0.75mol % of H2SO4 (E) TGP + 1.0 mol % of H2SO4. FT-IR Analysis. Fig. 2 shows the FT-IR spectra of pure and H2SO4 doped TGP crystals as it were recorded in the region 400-4000 cm-1. P-O stretching vibrations are expected in the region 1040-910 cm-1 [13] which is observed in IR at ~1042 cm-1. OH stretching mode is observed at ~3430 cm-1 and S=O stretching mode is observed at ~1390 cm-1. Its absence in the pure TGP spectrum and its presence in the doped TGP spectra clearly indicate the presence of H2SO4 in the lattice of TGP crystal. C=O stretching vibrations in saturated aliphatic aldehydes, ketones and acids have frequencies in range 1740–1700 cm−1. In amides, the frequency is lowered to 1690 cm−1 [14], which is due to existence of resonance structures. C=O stretching band is observed at 1590 cm-1. The deformation vibration of the carboxylate ion is observed at 682.95 cm-1. C=O and NH2 stretching vibrations are shifted and strongly evidences of intra-molecular interactions.

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Fig. 2. FT IR Spectra (A) Pure TGP , (B) TGP + 0.25mol % of H2SO4, (C) TGP + 0.50 mol % of H2SO4 (D) TGP + 0.75mol % of H2SO4 (E) TGP + 1.0 mol % of H2SO4. Thermal Analysis. Thermogravimetry (TG) and differential thermal analysis (DTA) of pure and H2SO4 doped TGP were carried out at room temperature to 730ºC and the thermograms are depicted in Fig.3. In pure TGP, up to 200ºC there is no weight loss which reveals that the compound is devoid of physically adsorbed water and water of crystallization [15]. Slight variations appears in the TGA traces of H2SO4 doped TGP crystals with various concentrations 0.25, 0.50, 0.75 and 1.0 mole %. The decomposition of the compound takes place in single stage. Between 250ºC and 500ºC the weight loss of 72% is observed or the compound for pure TGP. This weight loss is due to the loss of glycine fragments in the compound. This weight loss is decrease as the concentration increases. The variation of experimental and the formulated weight losses are insignificant. At 730ºC, almost 29 % of the compound remains as residue. An exothermic peak observed in DTA at 238ºC complement to H 2SO4 admixtured TGP are due to the decomposition of the compound. Pure TGP crystal showed a major weight loss (∼49 wt.%) in the temperature range between 218 and 268ºC. This can be attributed to the decomposition of glycine into CO2 and SO4. DTA curve revealed a sharp peak at 213ºC corresponding to the decomposition of glycine. Further increase in temperature resulted in the removal of HCl in the form of H2O with a total weight loss of 24 wt.%. Thus DTA curve of TGP crystal also showed to be due to combustion of glycine and removal of carbon.

a) b) c) d) e) Fig. 3. TG DTA (a) Pure TGP, (b) TGP + 0.25mol % of H2SO4, (c) TGP + 0.50 mol % of H2SO4, (d) TGP + 0.75mol % of H2SO4, (e) TGP + 1.0 mol % of H2SO4. Dielectric studies. Exact phase transition temperature of all ferroelectric crystals are studied and also the effects of dopants on the phase transition temperature were identified using dielectric measurements. The capacitance (Ccrys) and dielectric loss (tan δ) of the grown crystals (pure and H2SO4 added TGP) were measured using an LCRZ meter to an accuracy of ±2C with frequency range (100Hz to 1MHz) at various temperatures ranging from 300C to 1500C. The dielectric studies of pure and H2SO4 added TGP crystals were performed by selecting high transparency rectangular shaped crystal plates of appreciable dimensions and the samples were coated with good quality graphite to obtain a good conductive surface layer. The variation of dielectric constant with MMSE Journal. Open Access www.mmse.xyz

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temperature for varying frequencies is shown in Fig.4. The dielectric constant is low at low temperature region and then increases with temperature for pure and H2SO4 admixtured TGP crystals, reaching maximum at the Curie point Tc. This rapid increase may be due to the space charge polarization of thermally generated carriers [16]. The sharp peak at Tc reveals that the nature of the grown crystal was of continuous phase transition. Above Tc, the dielectric constant decreases, following the Curie-Weiss law. It show that all the grown crystals (pure and doped TGP) behave as para electric before 328K-333K and becomes ferroelectric above 328K-333K, at varying frequencies. Thus all grown crystals may exhibit ferroelectric nature at higher temperatures. The variation of dielectric loss with temperature at different frequencies is shown in Fig.5. Purity and perfection of the crystal will depend on the space contribution and it has significant influence in the low frequency region. The dielectric loss is due to the resistive component that makes them loosy, so that they dissipate some of the applied ac energy. The low value of dielectric loss at high frequency suggest that all the samples possess enhanced optical quality with lesser defects and thus have vital importance for NLO applications [17]. The dopants (H2SO4) shifted the phase transition temperature slightly, but the shift was not considerable compared with the deuteration effect [18]. Fig. 6 shows the ac electrical conductivity of the sample as a function of temperature. Two different regions can be distinguished. At T , 328-333K (region I), the curve shows a positive temperature coefficient of the conductivity in accordance with conventional semiconducting behavior [19], where the conductivity increases with increasing temperature and thus the electrical activation energy ofthis sample is positive in region I. On the other hand, the decrease of conductivity at Tc 328-333K (region II) results from the scattering of carriers by phonons due to lattice vibrations at these elevated temperatures. The slope and temperature range of this region varies widely depending on the nature and structure of the sample [20]. From the results, it is observed that the dielectric parameters are found to be increased when TGP crystals are doped with H2SO4. The activation energy of the crystal is also calculated from an Arrhenius plot using the relation: σac = σ0 exp[-Ea/kT] where σ0 is a constant depending on material, Ea is the activation energy, T the absolute temperature and k is the Boltzmann’s constant. The above equation can be rewritten as ln σac = lnσ0 -Ea/kT A plot of ln σdc versus 1000/T gives -Ea/k as the slope and ln σdc as the intercept. Activation energies at the ferroelectric phase (above Tc) of the grown crystals were estimated using the slopes of the line plots, [E= -(slope)k x1000] and are found to be 0.5255eV,0.2039eV, 0.2454eV, 0.2454eV, and 0.5851eV respectively for pure and H2SO4 doped TGP (0.25,0.50, 0.75 and 1.0 mol %) crystals. A similar range of activation energy values have been reported which infer that pure and sulphuric acid added crystals will behave at high temperatures as a super-ionic conductor [5]. The lower activation energies estimated from electrical conductivity studies suggests that the material contains less number of charge carriers for conduction process and the dielectric behaviour is very well understood.

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Fig. 4. Dielectic constant.

Fig. 5. Dielectic loss.

Fig. 6. AC conductivity. UV Analysis. Grown crystals are optically characterized by UV-Vis spectral analysis are shown in Fig 7. The optical spectrum recorded revealed that grown crystals have lower cut off wavelength at 209, 209, 217, 208 and 212 nm respectively for the pure and H2SO4 (0.25, 0.50, 0.75 and 1.0 mole % concentrations) doped TGP which corresponds suitable for optical applications. TGP crystals are useful as a good non-linear material and for optoelectronics applications due to low cut off wavelength and a very good transparency [21]. Table 2. UV Absorbance, band gap. UV

Absorbance(a.u)

Pure TGP 0.25 mol % H2SO4 doped TGP 0.50 mol % H2SO4 doped TGP 0.75 mol % H2SO4 doped TGP 1.0 mol % H2SO4 doped TGP

209 217

5.94 5.72

216

5.75

210

5.91

213

5.83

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Band Gap

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Fig. 7. UV Absorbance Spectra. Summary. Good optical quality crystals of pure and H2SO4 (0.25, 0.50, 0.75 and 1.0 mole %) doped TGP crystals were grown successfully from aqueous solution by slow evaporation technique. PXRD analysis reveals high crystalline nature of the grown crystals and are belongs to monoclinic crystal system. Changes in the relative intensity and peak positions of H2SO4 only acted as the additive rather than as dopant. The spectral investigations by IR spectroscopy strongly suggested the Zwitter and glycinium ions were present in both pure and H2SO4 admixtured TGP crystals. Pure and H2SO4 doped TGP crystals are useful as a good non-linear material and for optoelectronics applications due to low cut off wavelength and are transparent to the entire visible region, which shows the wide window for nonlinear applications. The observed low dielectric constant and low dielectric loss suggests that the grown crystals are suitable for NLO applications in accordance with Miller’s rule. References [1] H.O. Marcy, M.J. Rosker, L.F. Warren, P.H. Cunningham, C.A. Thomas, L.A. Deloach, S.P.Velsko, C.AEbbers, J.H. Liao, M.G.Kanatzidis, Opt.Lett.20 (1995) 252. [2] M.D. Aggarwal, J. Choi, W.S. Wang, K. Bhat, R.B. Lal, A.D. Shields, B.G. Penn, D.O. Prazier, J.Cryst. Growth 204(1999)179 [3] N. Tyagi, N. Sinha, B. Kumar, Curr. Appl. Phys. 14 (2014) 156–160. [4] N. Sinha, N. Goel, B.K. Singh, M.K. Gupta, B. Kumar, J. Solid State Chem. 190(2012) 180–185. [5] A. Wojciechowski, I.V. Kityk, G. Lakshminarayana, I. Fuks-Janczarek, J.Berdowski, E. Berdowska, Z. Tylczynski, Physica B 405 (2010) 2827–2830. [6] T. Vijayakumar, I. Hubert Joe, C.P. Reghunadhan Nair, V.S. Jayakumar, J. Mol.Struct. 877 (2008) 20–35. [7] K. Ozga, A.H. Reshak, J. Berdowski, Z. Tylczynski, A. Wojciechowski, A. Slezak,I.V. Kityk, K. Ozga, A.H. Reshak, J. Berdowski, Z. Tylczynski, A. Wojciechowski,A. Slezak, I.V. Kityk, Mater. Lett. 64 (2010) 1–3. [8] S. Dacko, Z. Czapla, J. Baran, M. Drozd, Phys. Lett. A 223 (1996) 217–220. [9] R. Muralidharan, R. Mohankumar, P.M. Ushasree, R. Jayavel, P. Ramasamy, J. Cryst. Growth 234 (2002) 545–550. [10] E. Mihaylova, S.T. Stoyanov, Phys. Status Solidi. A 154 (1996) 797–802. [11] G. Ravi, G. Arunmozhi, S. Anbukumar, P. Ramasamy, Ferroelectrics 174 (1995) 241–247. [12] A. Huttunen and P. Torma, J. Appl. Phys. 91 (2002) 3988. MMSE Journal. Open Access www.mmse.xyz

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[13] B.C. Smith, Infrared Spectral Interpretation, A Systematic Approach, CRC Press, Washington, DC, 1999. [14] G. Socrates, Infrared Characteristic Group Frequencies, Wiley-IntersciencePublication, 1980 [15] P. Muthuraja, M. Sethuram, M. Sethu Raman, M. Dhandapani and G. Amirthaganesan, J. Mol. Struct. 1053 (2013) 5-14 [16] P. Selvarajan, B.N. Das, H.B. Gon, K.V. Rao, J. Mater. Sci. 29 (1994) 4061. [17] A.Selvam, S.Pandi, V.Rajendran, S.Gnanam, S.Selvakumar, Der Pharma Chemica, 2012, 4(1), 228. [18] J. Baran, M.S. Sledz, R. Jakubas, G. Bator, Phys. Rev. B 55 (1997) 169–172. [19] F. Yakuphanoglu, Ph.D Thesis, Firat University, Elazig, Turkey (2002). [20] J.N. BabuReddy, S.Vanishri, Ganesh Kamath, Suja Elizabeth, H.L. Bhat, D.Isakov, M.Belsley, E.deMatosGomes, T.L.Aroso, J. Cryst. Growth, 311(2009)4044–4049. [21] S. Bhandari, N. Sinha, G. Ray, B. Kumar, Enhanced optical, dielectric and piezoelectric behavior in dye doped zinc tris-thiourea sulphate (ZTS) single crystals, Chem. Phys. Lett. 591 (2014) 10–15, DOI: 10.1016/j.cplett.2013.11.007 Cite the paper M.R. Meera, S.L. Rayar, V. Bena Jothy (2017). Effect of Hydrochloric Acid (HCl) on Synthesis and Anisotropic Phenomena of Triglycine Phosphate (TGP) Single Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.60.6.225

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Structural Properties of Bioactive Molecule Naphthalene 2-Sulfonic Acid36 R. Mini1, T. Joselin Beaula1, I. Hubert Joe2, V. Bena Jothy1, a 1 – Department of Physics and Research Centre, Women’s Christian College, Nagercoil -629 001, TamilNadu, India 2 – Department of Physics and Research Centre, Mar Ivanios College, Nalancira 695015, Kerala, India a – benaezhil@yahoo.com DOI 10.2412/mmse.64.50.546 provided by Seo4U.link

Keywords: NSA, DFT, UV-Vis spectra, NBO, molecular docking.

ABSTRACT. Naphthalene 2-sulfonic acid (NSA) and its derivatives are the most important class of organic compounds and are important products of industrial chemical processes. . Bioactive molecule NSA was performed by means of Density Functional Theoretical (DFT) method using standard B3LYP/6-31G (d,p) basis set implemented with Gaussian’09 software package. NBO analysis were performed to provide valuable information about various intermolecular interactions. Optical properties of the NSA molecule were studied using UV-Vis spectral analysis. In addition, Molecular docking was performed for the different receptors for calculating binding affinities and predicting binding sites.

Introduction. Bioactive substance is experiencing a growing interest of phytomedicines, including their clinical applications, standardization, quality control, mode of action and potential drug interactions have emerged as one of the most exciting developments in modern therapeutics and medicine. Bioactive compounds are still regarded as a valuable pool for discovering novel mode of action. [1] Substituted sulfonic acid is used as analytical reagent in the manufacture of disinfectants, antiseptics, deodorants and medicines. It is also used for disinfecting skin and for the treatment of minor wounds and puriﬁcation of drinking water in case of amoebicidal and bactericidal emergencies [2]. Naphthalene is used to make dyes, explosives, plastics and lubricants. Naphthalene is very dangerous to human health especially children who may mistake naphthalene balls for candy. It enters human through inhalation or passing through the skin. Because of their spectroscopic properties and chemical significance of NSA have been studied extensively by spectroscopic and theoretical methods. A systematic study on the molecule structure and vibrational spectra will help in understanding the property of NSA molecule. Present study intends to fully exploit the structural and biological characterization of NSA along with DFT calculations to investigate the spectral investigations using UV–vis, Docking and NBO analysis of NSA molecule. Experimental and Computational details UV–visible absorption spectrum of the sample was measured, using UV–vis JASCO (V-570) UV/VIS/NIR spectrometer. DFT Computation were carried out using Gaussian'09 program [3] at B3LYP/6-311G(d,p) level. Natural bond orbital (NBO) analysis [4] have been using NBO 3.1 program to understand inter- and intra-molecular delocalization. Optimized structure was docked using Auto Dock Tools (ADT) Version 1.5.4 revision 30[5]. Results and Discussion Geometrical structures. Structure parameters of the NSA molecule were calculated using DFT / B3LYP/6-311++G(d,p) basis set has been listed in Table.1 . and the molecular structure with atom © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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numbering scheme adopted in this study is shown in Fig.1. Bond length of S18-O21 (1.6497Å) is higher than other S-O bond lengths S18-O19 and (1.4575Å) and S18-O20 (1.4643Å) which is due to the attachment of hydrogen atom with it. Hydrogen sulfate anion is highly distorted from its tetrahedral arrangement which is manifested from its bond angles O19-S18-O20 (121.07°), O19-S18-O21(108.43°), S18-O21-O22(106.04°) and O20-S18-O21(106.19°). Presence of strong intra-molecular hydrogen bond interactions C11-H16…O19 has been confirmed by the measured distances C11…O19 which is 2.9431Å lying within the range <3 Å for hydrogen interaction [6].

Fig. 1. OptimizedstructureofNaphthalene-2-sulfonicacid. Table 1. Optimized Bond lengths (Å), Bond angles (°) and Dihedral angle (°) of Naphthalene 2sulfonic acid byB3LYP/6-31g(d,p)basis sets. Bond Length S18-O19 S18-O20 S18-O21 C1- C6 C1-H8 C2- C3 C2-H9 C3-C4 C3-C10 C4-C5 C4-C11 C5-C6 C5-H12 C6-H13 H7-C10 C10-C15 C11-C14 C11-H16 C14-C15

Theo. (Å) 1.4575 1.4643 1.6497 1.4163 1.0859 1.4196 1.0865 1.4336 1.4228 1.4206 1.419 1.3761 1.0864 1.0856 1.0863 1.3734 1.3755 1.0849 1.4169

Bond angle O19- S18-O20 O19- S18-O21 O20- S18-O21 S18-O21-O22 C1-C2-C6 C2-C1-H8 C6-C1-H8 C1-C2-C3 C1-C2-H9 C3- C2 -H9 C2-C3-C4 C2-C3 -C10 C4- C3-C10 C3-C4 -C5 C3-C4 -C11 C5 -C4-C11 C4 - C5 - C6 C4 - C5 - H12 C6 -C5 - H12

Theo. (º) 121.07 108.43 106.19 106.03 120.52 119.97 119.51 120.69 120.45 118.85 118.73 122.17 119.10 119.21 118.99 121.81 120.57 118.81 120.62

Dihedral angle (º) C6- C1-C2-C3 C2- C1-C6- C5 C1-C2-C3- C4 C1-C2-C3-C10 C1-C2-C3- C4 C1-C2-C3-C10 C2-C3- C4- C5 C2-C3- C4-C11 C10-C3- C4- C5 C10-C3- C4- C11 C2-C3- C10- C15 C4- C3- C10-C15 C3- C4- C5-C6 C11- C4- C5-C6 C5- C4- C11-C14 C4-C5- C6- C1 C3- C10- C15-C14 C4- C11- C14- C15 C11- C14- C15 -C10

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Theo. (º) -0.06 0.03 -0.01 179.69 -0.003 179.69 0.09 -179.97 -179.60 0.32 -179.94 -0.25 -0.13 179.97 179.96 0.06 -0.18 -0.49 0.57

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To interpret the presence of intermolecular and intramolecular charge transfer interactions, the second order perturbation energies were calculated using NBO analysis. Electron occupancies of lone pair and anti-bonding orbitals of NSA molecule are given in Table .2. To investigate energy features of intramolecular non-bonded S···O interactions. Existence of C-S···O interactions is confirmed due to interaction between lone pair oxygen atoms O19 and O20 with C14-S18 having stabilization energies of 16.48 and 16.62 kJ/mol respectively. Central sulphur atom is SP 2 hybridised with 26.89% s character and 71.67% p character that shortens bond length of C-S (1.78 Å). Intramolecular charge transfer is obtained by orbital overlapping within ring system between π C1 - C2 and π*C5-C6 having a stabilization energy of 17.07 kJ/mol. Table 2. Second order perturbation theory analysis of Fock matrix in NBO basis. Donor (i)

ED(i) (e)

Acceptor (j)

ED(j) (e)

E(2)a

F(i,j) c

(kJ mol-1)

E(j)– E(i)b (a.u)

(a.u)

LP2O19

1.80507

σ*C14-S18

0.18460

16.48

0.45

0.077

LP2O19

1.80507 σ* S18-O 20

0.14000

12.72

0.59

0.078

LP3 O19

1.77036 σ*S 18-O 21

0.30690

31.07

0.37

0.097

LP 2 O20

1.80871 σ*C14 - S18

0.18460

13.56

0.45

0.070

LP 2 O20

1.80871 σ*S18 - O19

0.14067

16.62

0.59

0.090

LP 3 O20

1.78564 σ*S18 - O21

0.30690

31.70

0.37

0.099

LP 2 O21

1.93961 σ*S18 - O19

0.14067

7.72

0.65

0.065

πC11-C14

1.76297

π*C10-C15

0.22653

17.47

0.32

0.067

πC10 - C15

1.73639 π*C11 - C14

0.02239

17.22

0.28

0.063

πC 1 - C 2

1.72875

0.24118

17.07

0.30

0.064

π*C5 - C6

a-E(2) means energy of hyperconjugative interactions; b-Energy difference between donor and acceptor i and j NBO orbitals; c-F(i,j) is the Fock matrix element between i and j NBO orbitals. UV-visible spectra To investigate UV–vis absorption spectrum of NSA molecule dissolved in D 2O is shown in Fig. 2 and theoretical values with combined experimental values in Table.3. In maximum absorption values are 309 and 302 nm and computed at 307 and 299 nm. Experimental band at 309 nm is attributed mainly to HOMO→LUMO transition with 74% contribution. This transition is predicted as π→π* transition. In this case the energy transitions are in reasonable agreement with experimental results. Calculated value of electrophilicity index describes the biological activity. Electronic band transitions can be well understood from the plot of (αhν) 2 verses photon energy as depicted in Fig 3. The wide optical band gap of NSA is found to be 4.7 eV suggesting its suitability for electronics applications.

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Fig. 3. (h ) vs. photon energy (hν).

Fig. 2. UV-Vis.Transmittance Spectrum.

Table 3. UV–vis excitation energy and oscillator strength for NSA. Exp.Wave Cal.Wave Energy(eV) Osc.Strength Symmetry Major contributes No. length(nm) length(nm) 1 309 307 34362.68224 0.0386 Singlet-A H-1->LUMO (10%), HOMO->LUMO (74%) 2 302 299 36252.45232 0.0121 Singlet-A H-1->LUMO (38%), HOMO->LUMO (19%), HOMO->L+1 (42%) 3 217 45945.6904 0.6458 Singlet-A H-2->LUMO (36%), H-1->LUMO (29%), HOMO->L+1 (23%) Molecular Docking Protein–ligand interactions play a critical role in the distribution, metabolism and transport of small molecules in biological systems and processes [7]. Docking is performed for one receptors (PDB ID1GSK) and the ligand. Best docked conformations was found to have the lowest binding energy and the greatest number of members in the cluster, indicating convergence. Least energy represents the easy binding characters of ligand and receptor. The binding mode as per amino acid residue is predicted to be the part of the binding site in Fig. 4. where LYS can make hydrogen bonds with SO3H of NSA can make hydrogen bonds with oxygen.

Fig. 4. Docked conformation of ligand.

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Summary. NSA molecule under investigation has wide biological applications. Natural bond orbital analysis performed in this study gives information about the molecular species which are responsible for more chemical stability.In UV spectra maximum absorption wavelengths and their excitation energies predicted in this study belong to π→π* transition. Moreover, molecular docking simulations have been done to test the biological inhibition activity against inﬂammation. The results showed that NSA molecule has potential activity against inﬂammation. Refernce [1] D Engelmeier, F Hadacek, Elsevier Sci. Ltd, 423-467 (2006). [2] S. Sebastian, S. Sylvestre, N. Sundaraganesan, M. Amalanathan, S. Ayyapan,,K. Oudayakumar, B. Karthikeyan ,Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy ,107, 167– 178(2013). [3] M. J. Frisch etal. Gaussian 09, Revision D.01, Gaussian, Inc., Wallingford CT, (2010). [4] E.D. Glendening, A.E. Reed, J.E. Carpenter, F. Weinhold, NBO Version 3.1,Theoretical Chemistry Institute and Department of Chemistry, University ofWisconsin, Madison, (1998). [5] G.M. Morris, R. Huey, W. Lindstrom, M.F. Sanner, R.K. Belew, D.S. Goodsell, A.J.Olson, J. Comput. Chem. 16, 2785 (2009). [6] S. Gunasekaran, R.A. Balaji, S. Kumeresan, G. Anand, S. Srinivasan, Can. J. Anal. Sci. Spectrosc. 53 149–162 (2008). [7] U. Kragh-Hansen, Molecular aspects of ligand binding to serum albumin, Pharmacol. Rev. 33, 17–53(1981). Cite the paper R. Mini, T. Joselin Beaula, I. Hubert Joe, V. Bena Jothy (2017). Structural Properties of Bioactive Molecule Naphthalene 2-Sulfonic Acid. Mechanics, Materials Science & Engineering, Vol 9. 10.2412/mmse.64.50.546

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Fluorescence Emission and Decay Time Studies on Doped 1, 3, 5Triphenylbenzene Scintillator Crystal Grown by Solution Growth Technique 37 N. Durairaj1, S. Kalainathan1, a, R. Kumar2 1 – Centre for Crystal Growth, VIT University Vellore-632014, Tamilnadu, India 2 – Nuclear and Radioanalytical Chemistry, IGCAR, Kalpakkam-603102, Tamilnadu, India a – kalainathan@yahoo.com DOI 10.2412/mmse.4.45.791 provided by Seo4U.link

Keywords: organic scintillator, fluorescence, decay time, scintillator detector.

ABSTRACT. Detection of fast neutrons in the presence of gamma radiation background is possible in the existence of two decay fluorescence of organic molecules. Doped organic molecules are enhancing the fluorescence emission and decay time which enables the large events of neutron-gamma detection. The present work is investigate the organic scintillator crystal 1,3,5-triphenylbenzene (3PB) doped with 1,4-diphenyl-1,3-butadiene (DPB) and 2,5-diphenyloxzole (PPO) with different concentration of mole percentage ratios (0.01, 0.03, 0.05, & 0.07). The fluorescence emission and decay time studies were carried out which reveals that importance of growing 3PB scintillator crystal. Among the four different concentrations, 0.01mol% of DPB and 0.05mol% of PPO obtained the maximum emission intensity. Fluorescence decay time was calculated by time-correlated single photon counting (TCSPC) method which reveals the reduction of decay time compare to pure 3PB and other organic scintillators.

Introduction. Scintillation detection is a high sensitive technique to identify the invisible radiations. To search the materials for efficient scintillation detection for high-energy particles in radiation background which begins in the mid of the 20th century has directed to a number of single crystal scintillators [1]. The particle discrimination in complex radiation field is possible by two decay (prompt and delayed) fluorescence molecules. Some of the organic single crystals, which is existing two decay fluorescence implemented for the neutron-gamma discrimination in high energy radiation field [2]. Nowadays it is considered to make industrialize scintillation detectors to be a base for security and environment control systems, as well as for radiation medicine [3, 4]. However, the conventional crystal scintillators have a number of unavoidable drawbacks, such as high production cost, specialised equipment required for its production as well as difficulties in obtaining large area scintillators. Hence overcome this issues many researchers has found new organic scintillators and grown the larger single crystals with low-cost techniques [5-7]. 3PB is the one of organic scintillator crystal; which gives the better pulse shape discrimination [7]. The present authors also have grown the larger unidirectional 3PB single crystal by Sankaranarayanan-Ramasamy (SR) method and reported decay time and other preliminary studies [8]. For the scintillator application, a larger light output and shorter decay time would be most welcomed to cover the large events of particle discrimination [9]. But 3PB has lower light output value [7, 8]. Hence, we are motivated to improve the light output of 3PB by an addition of small bright fluorophores such as DPB and PPO with the pure material (3PB). Experimental Technique. Pure and doped 3PB single crystal is grown by slow evaporation technique. According to the solubility data [8], at room temperature 22.54g of the 3PB (solute) is dissolved in 100ml tetrahydrofuran solvent. The distribution of dopants DPB and PPO is calculated as a ratio of the solute concentration in solution. The 3PB is doped by DPB and PPO of different © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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concentration ratios 0.01, 0.03, 0.05, and 0.07. The saturated solution is filtered and transferred into a crystal growth vessel (petri dish) by using the Whatman filter paper. The growth vessel with the saturated solution was tightly covered with aluminium foil with few fine holes, which make the controlled evaporation of the solvent. Due to continue evaporation of the solvent, the solution will attain the supersaturation. When the solution attains the supersaturation, then it initiated the nucleation. After 16 days, spontaneously nucleated good optical quality crystals harvested. Similar size of the harvested crystal (Fig.1a&b) was selected for fluorescence emission and decay time analyses. The fluorescence spectrum was recorded using Edinburgh FLS 980 spectrometer with excitation wavelength 300 nm at room temperature. The emission spectrum of pure, DPB and PPO doped 3PB crystals are shown in Fig. 2. The lifetime measurement was carried out by TimeCorrelated Single Photon Counting (TCSPC) method by using the Jobin Yuvon (FL3-11) spectrofluorometer with the emission wavelength 360 nm. Table.1 reveals some scintillation properties of 3PB and DPB and PPO molecules.

Fig. 1. (a) DPB Doped 3PB crystals, (b) PPO Doped 3PB crystals grown by slow evaporation technique. Table 1. Some scintillation properties of host and guest molecules. S.No.

Properties

3PB (C24H18) (Host) [8]

DPB (C16H14) PPO (C15H 11NO) (Guest) [9] (Guest) [9]

Excitation

300 nm

320 nm

300 nm

Emission

360 nm

350 nm

416 nm

Decay time

12 ns, 30ns

6 ns

Result and Discussion Fluorescence studies. The result of doping DPB and PPO in 3PB single crystal is increasing the light output values or increasing the number of photons produced. Increasing light output values in a doped single crystal is compared with undoped one, which can be explained by the active transfer of electronic excitation energy from the host molecules (3PB) to the guest molecules (DPB and PPO). At the same time, the distribution of guest molecules also is important in 3PB. When increasing the concentration of guest molecules, there is a chance to suppress the light output values which is due to concentration quenching effect [10]. The emission spectrum was measured for the pure and all concentration of doped crystals (Fig.2 a&b). It is noticed that the concentration of 0.01 mol% of DPB and 0.05 mol% of PPO doped crystals shows the maximum emission intensity which is due to the exchange coupling and triplet mobility increased in doped crystals. The decrease in fluorescence intensity above these concentrations (0.01 mol% of DPB and 0.05 mol% of PPO) of doped crystals MMSE Journal. Open Access www.mmse.xyz

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is due to concentration quenching effect [11]. The fluorescence intensity of pure 3PB is lower than compare to doped crystals which are due to the less populated excited states in it. The fluorescence spectra are the evidence of dopant incorporation into the 3PB crystals.

b b PPO

Fig. 2. Fluorescence spectra of (a) DPB doped crystals (b) PPO doped crystal excited at 300nm. Fluorescence decay analysis. A distinctive feature of the organic scintillator as a detector application is to exhibit different lifetime at the same emission wavelength. The lifetime profile was calculated by time-correlated single photon counting method (TCSPC) [12]. Figure 3 (a, b) reveals the decay time spectrum of the 0.01% DPB 0.05% PPO doped crystals. The analysis of decay time measurement was fitted with the two exponential decay components: â&#x2C6;&#x2019;đ?&#x2018;Ą

â&#x2C6;&#x2019;đ?&#x2018;Ą

đ??š(đ?&#x2018;Ľ ) = đ??´1 đ?&#x2018;&#x2019; đ?&#x153;?1 + đ??´2 đ?&#x2018;&#x2019; đ?&#x153;?2

(1)

where A1 and A2 are amplitudes of prompt and delayed emissions respectively, Ď&#x201E;1 and Ď&#x201E;2 are lifetimes. The calculated fluorescence lifetime of the pure, 0.01mol% of DPB and 0.05mol% of PPO doped crystal is listed in Table.1. The fast scintillation decay time in organic molecules is typically 2-30ns. From the literature, the existing organic scintillator lifetime is listed with the present work. Compare to earlier reports the present 3PB crystal doped with 0.01% of DPB and 0.05% of PPO exhibit the very short decay time. The prompt fluorescence corresponds to direct de-excitation of singlet energy level transition and delayed emission was due to collisional interaction pairs of molecules in the lowest excited triplet state. The significant of the collisional interaction of triplet energy level was used for neutron detection in an organic scintillator [2, 12].

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Fig. 3. Fluorescence decay curve (a) 0.01% DPB (b) 0.05% PPO doped 3PB crystal. Table 2. Comparison of scintillation decay time with existing materials. S.No.

Compound

Prompt

Delayed

References

Anthracene

30 ns

[6]

Stilbene

4.5 ns

[6]

Pure Naphthalene

14.4 ns

78.6 ns

[2]

PPO doped Naphthalene

7.5 ns

50.2 ns

[8]

P-terphenyl

3.3 ns

[9]

Pure 3PB

12 ns

30 ns

[5]

0.05% PPO doped 3PB

3.8 ns

17.8 ns

Present work

0.01 DPB doped 3PB

2.08 ns

11.37 ns

Present work

Summary. DPB and PPO doped 3PB crystal was grown by slow evaporation technique. The distribution of dopant was in 3PB analysed by different concentration. Among the four different concentrations, 0.01mol% of DPB and 0.05mol% of PPO obtained the maximum emission intensity. The fluorescence emission and decay time studies were carried out which reveals that importance of growing 3PB scintillator crystal. The fluorescence spectra are the evidence of the dopant incorporation into the 3PB crystals. Fluorescence decay time was measured by time-correlated single photon counting (TCSPC) method which reveals the reduction of decay time compare to pure 3PB and other organic scintillators. The present study exhibits the maximum emission intensity and short decay time (2.08ns) for the 0.01mol% DPB doped crystal which is better result compare to the pure and scintillator crystals. It is due to the exchange coupling and mobility of triplet in the guest and host molecules. Acknowledgement The authors 1 and 2 thank the DAE-BRNS (Project sanction no. 34/14/22/2014-BRNS0294 dated 16 May 2014) for providing financial support and the VIT University management for their constant encouragement. The authors would like to thank Prof. C.K.Jayasankar and MoU-DAE- BRNS Project (No.2009/34/36/BRNS/3174), Department of Physics, S.V. University, Tirupati, India for extending the experimental fluorescence facility. References MMSE Journal. Open Access www.mmse.xyz

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[1] C.R. Ronda, Luminescence: From Theory to Applications, Wiley-VCH, Weinheim, 2008. DOI:10.1002/9783527621064.ch5 [2] N. Zaitseva, J. Newby, S. Hamel, L. Carman, M. Faust, V. Lordi, N. Cherepy, W. Stoeffl, S. Payne, Neutron detection with single crystal organic scintillators, https://e-reportsext.llnl.gov/pdf/375697.pdf [3] http://www.cryosbeta.kharkov.ua/organic.php [4] www.inradoptics.com, White paper, Production of stilbene for fast neutron detection [5] G.Hull, Natalia P. Zaitseva, Nerine J. Cherepy, Jason R. Newby, Wolfgang Stoeffl, and Stephen A. Payne, IEEE Transactions On Nuclear Science, 56 (2009) 899-903 DOI:10.1109/TNS. 2009.2015944 [6] Edgar V. van Loef, Jarek Glodo, Urmila Shirwadkar, Natalia Zaitseva, Kanai S. Shah, Novel Organic Scintillators for Neutron Detection, IEEE (2010) 1007-1009. DOI: 10.1109/NSSMIC.2010.5873916 [7] Natalia Zaitseva, Leslie Carman, Andrew Glenn, Jason Newby, Michelle Faust, Sebastien Hamel, Nerine Cherepy, Stephen Payne, Application of solution techniques for rapid growth of organic crystals, Journal of Crystal Growth 314 (2011) 163–170. DOI:10.1016/j.jcrysgro.2010.10.139 [8] N.Durairaj, S.Kalainathan, M.V.Krishnaiah, Investigation on unidirectional growth of 1,3,5Triphenylbenzene by Sankaranarayanan-Ramasamy method and its characterization of life time, thermal analysis, hardness and etching studies, Material Chemistry & Physics, 181 (2016) 529-537. DOI:10.1016/j.matchemphys.2016.06.090 [9] G. F. Knoll, Radiation Detection and Measurement, 3rd Ed. New York: Wiley, 2000. [10] N. Balamurugan, A. Arulchakkaravarthi, P. Ramasamy, Growth of 2,5-diphenyloxazole-doped naphthalene crystal by Bridgman method and its fluorescence studies, Journal of Crystal Growth 310 (2008) 2115 – 2119, DOI:10.1016/j.jcrysgro.2007.10.047 [11] S. Selvakumar, K.Sivaji, A.Arulchakkaravarthi, S.Sankar, Enhanced fluorescence and time resolved fluorescence properties of p-terphenyl crystal grown by selective self-seeded vertical Bridgman technique, Materials Letters 61 (2007) 4718 – 4721, DOI:10.1016/j.matlet.2007.03.018 [12] Natalia Zaitseva, Andrew Glenn, Leslie Carman, Robert Hatarik, Sebastien Hamel, Michelle Faust, Brandon Schabes, Nerine Cherepy, and Stephen Payne, Pulse Shaped Discrimination in Impure and Mixed Single Crystal Organic Scintillators. IEEE transactions on nuclear science, vol. 58, no. 6, December 2011 DOI:10.1109/tns.2011.2171363 [13] S.Selvakumar, K.Sivaji, A.Arulchakkaravarthi, N.Balamurugan, S.Sankar, P.Ramasamy, Growth of high-quality naphthalene single crystals using selective self-seeding vertical Bridgman technique (SSVBT) and its characterization, Journal of Crystal Growth 282 (2005) 370–375 DOI:10.1016/j.jcrysgro.2005.05.022. Cite the paper N. Durairaj, S. Kalainathan, R. Kumar, (2017). Fluorescence Emission and Decay Time Studies on Doped 1, 3, 5-Triphenylbenzene Scintillator Crystal Grown by Solution Growth Technique. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.4.45.791

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Bulk Crystal growth and Characterization of Organic Nonlinear Optical Crystal: 2-(2,4-dimethoxybenzylidene) malononitrile (DMM)38 A. Priyadharshini1, S.Kalainathan1, a 1 – Centre for Crystal Growth, School of Advanced Sciences, VIT University, Vellore –632 014, India a – kalainathan@yahoo.com DOI 10.2412/mmse.56.31.690 provided by Seo4U.link

Keywords: DMM crystal, bulk crystal growth, single crystal XRD, FT-IR, UV-Vis-NIR spectral analysis, Z-scan technique.

ABSTRACT. Bulk organic nonlinear optical single crystal of 2-(2,4-dimethoxybenzylidene) malononitrile (DMM) with size up to 24×18×13 mm2 was successfully grown by slow evaporation solution growth technique. The single crystal Xray diffraction studies of the grown crystal exhibit that the crystal belongs to a monoclinic system with P21/n space group. The FT-IR spectrum confirms the various functional groups present in the grown crystal. The optical properties of the grown crystals were analyzed by UV–Vis-NIR spectral analysis. Third-order nonlinear optical behaviour of the title crystal was studied by Z-scan technique. All the finding results in the present work indicate that DMM has a potential application as a useful NLO candidate.

Introduction. In recent years, organic non-linear optical (NLO) crystals have gained considerable attention due to their relatively high nonlinearity and fast response. Particularly, third order nonlinear optical (TONLO) organic materials have gained much consideration because of their promising applications in optical switching, optical data processing, optical limiting, signal processing and ultrafast optical communications, etc [1,2]. The centrosymmetric organic crystals with good stability lead to third order susceptibility (χ(3)) and higher nonlinear absorption co-efficient (β) and fast response time for nonlinear optical properties. However, only very few organic materials could so far be crystallized in reasonable crystal size and optical grade to realize various applications. For the first time, we present here investigations on the bulk growth of DMM organic crystals and its different characterizations. Material synthesis and crystal growth. The title material of 2-(2,4-dimethoxybenzylidene) malononitrile (DMM) was synthesized by Knoevenagel condensation reaction method by using 2,4dimethoxybenzaldehyde and malononitrile stoichiometric ratio and dissolved in ethanol (25 ml). The above mixture solution was taken in the 100 ml round bottom flask (RBF) and 5 drops piperidine was added as a catalyst. The solution was refluxed at 65 ºC for 3h. The reaction mixture was cooled to ambient temperature. Yellowish salt was collected by filtration, washed with diethyl ether several times and then dried in an oven. The chemical reaction is shown in Fig. 1.

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Fig. 1. Chemical reaction. The dried product of DMM was dissolved in acetone at 35 ºC to form a saturated solution, and the solution was stirred using a motorized magnetic stirring device for 12 h to obtain a homogeneous solution. The solution was filtered into a 150 ml beaker using high-quality Whatman filter paper. The solvent was allowed to slowly evaporate at 35 ºC in a constant temperature water bath (accuracy of ± 0.01 ºC). Optical quality DMM crystals were harvested with dimensions 24×18×13 mm2 after a period of 22 days by slow evaporation solution growth technique. The grown DMM crystal is shown in Fig. 2.

Fig. 2. Photograph of as-grown DMM crystal. Results and discussions. Single crystal X-Ray diffraction analysis (SXRD). The single-crystal X-ray diffraction analysis of the grown crystal have been carried out to identify the structure and to estimate the lattice parameters. It reveals that the DMM crystal has crystallized in the monoclinic crystallographic system with centrosymmetric space group P21/n. The calculated unit cell parameters of the DMM crystal are a = 8.394 (8) A˚ ; b = 7.525 (2) A˚ ; c = 17.152 (8) A˚. The volume of the crystal is 1080.6 (2) Å 3. The obtained lattice parameter values are good agreement with the reported values [3] and thus confirmed the grown title compound. FT-IR spectral analysis. The FT-IR analysis of DMM was carried out to investigate the presence of functional groups and their vibrational modes. The sample was prepared by mixing DMM with KBr pellet. The spectrum was recorded in the wavenumber range 400- 4000 cm-1 using a BRUKER 66V FT-IR spectrometer and the spectrum is shown in Fig. 3. The broad envelope positioned between 3089 and 2976 cm-1 corresponds to the symmetric C-H stretching vibration. The strong absorption at 2220 cm-1 indicates the existence of C≡N stretching mode of nitrile group. The peak at 1467 and 1354 cm- 1 indicate the existence O-CH3 methyl group. The FT-IR spectrum confirms the formation of DMM crystal.

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725.23

570.93

511.14 435.91

929.69

848.68 804.32

1608.63 1560.41 1467.83 1354.03 1278.81 1209.37 1161.15 1120.64 1020.34

2220.07

2843.07

3089.96

2976.16

100

0 4000 DMM

3500

3000

2500

2000

1500

1000

500 1/cm

Fig. 3. FT-IR spectra of DMM. UV-Vis-NIR spectral analysis. The optical absorbance spectrum (AS) of DMM crystal was recorded between the wavelength range 400 and 1000 nm using a ELICO SL 218 double beam UV-Vis-NIR spectrometer. For this study, the an optically polished single crystal of thickness (t) 1.3 mm was used and the recorded absorption spectrum is shown in Fig 3. The lower cut-off wavelength is found to be 483 nm, and the crystals show good transmittance percentage in the range of 490–1000 nm. The transmittance nature in the entire visible and near IR region is the desired criteria for NLO applications [4].

Fig. 4. UV-Vis-NIR specra of DMM crystal. Z-Scan measurement. Single-beam Z-scan technique was employed to measure the third-order optical nonlinearities of the DMM crystal. The experiments were performed using a continuous HeNe laser of the wavelength of 632.8 nm, which was focused by a 30 mm focal length lens. The laser beam waist at the focus is measured to be 12.05 μm and the Rayleigh length is 0.72 mm. The sample was mounted on a translation stage (-Z to +Z) that was controlled by the computer to move along the Z-axis with respect to the focal point. An aperture 2 mm radius was placed in front of the transmission detector, and the transmittance was recorded as a function of the sample position on the Z-axis i.e., closed aperture (CA) Z-scan. For measuring the NLO absorption, the Z-dependent sample transmittance was taken without the aperture ie.,open aperture (OA) Z-scan. Actually, the nonlinear absorption coefficient (β) and nonlinear refractive index (n2) could be assessed by OA and CA ZMMSE Journal. Open Access www.mmse.xyz

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scan. The obtained results of the Z-scan curves in open and closed aperture modes are shown in Fig. 5 (a - b). The nonlinear refractive index (n2) can be obtained by the relation, given bellow:

n2 =

ΔΦo KIo Leff

(1)

where K is the wave number (K= 9.924 ×106 m-1 ), Io is the intensity of the laser beam at the focal point (Io = 26.50 MW /m2), and Leff is effective thickness of the grown crystal can be estimated as L eff = [1- exp(-αL)]/α, where L is the thickness of the crystal and α is the linear absorption coefficient. From the OA curve line, the nonlinear absorption coefficient (β) was estimated by,

β=

2 2ΔT Io Leff

(2)

where ΔT is the valley value at the OA data. The absolute value of the third-order nonlinear optical susceptibility (χ(3)) was calculated by using the equation [5],

χ

3

2 2 =  Re(χ (3) )  +  Im(χ (3) )    

1/2

(3)

where Re and Im are the real and imaginary part of the optical susceptibility. From the Z-scan data, the calculated value of χ(3) is 4.30 × 10−5 esu; n2 is 1.876 × 10−11 m2/W, and β is 2.537× 10−5 m/W. Thus, the overall experimental results indicate that DMM crystal has better NLO properties.

Fig. 5. (a) Open aperture Z-scan plot of DMM. (b) Closed aperture Z-scan plot of DMM. Summary. A bulk single crystal of DMM has been synthesized and grown by the slow evaporation method. The lattice parameter was confirmed by SXRD analysis. FT-IR study confirmed the formation of the desired material. UV-Vis-NIR spectral study showed that the grown crystal is MMSE Journal. Open Access www.mmse.xyz

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transparent in the entire visible region ranging from 490 nm to 1000 nm. A third-order nonlinear optical study of the DMM crystal reveals that a reverse saturation absorption (RSA) and a positive sign of nonlinear refractive index (n2), which are required for optical limiting applications. From the present investigation, we conclude that DMM is a new candidate for NLO device applications. Reference [1] Evans, C. C., Bagieu-Beucher, M., Masse, R., & Nicoud, J. F. (1998). Nonlinearity enhancement by solid-state proton transfer: a new strategy for the design of nonlinear optical materials. Chemistry of materials, 10(3), 847-854. DOI: 10.1021/cm970618g. [2] Delaire, J. A., & Nakatani, K. (2000). Linear and nonlinear optical properties of photochromic molecules and materials. Chemical Reviews, 100(5), 1817-1846.DOI: 10.1021/cr980078m. [3] Antipin, M. Y., Barr, T. A., Cardelino, B. H., Clark, R. D., Moore, C. E., Myers, T., & Timofeeva, T. V. (1997). X-ray Crystal Structures, Molecular Mechanics Calculations, and Calculations of the Nonlinear Polarizabilities (β and γ) of Dicyanovinylbenzene and Its Methoxy Derivatives, and Comparison with Experimental Values of β. The Journal of Physical Chemistry B, 101(15), 27702781. DOI: 10.1021/jp9628951. [4] Uma, J., & Rajendran, V. (2014). Growth and characterization of semiorganic NLO crystal of lglutamic acid hydrochlorobromide (LGHCB). Journal of Thermal Analysis and Calorimetry, 117(3), 1157-1163. DOI: 10.1007/s10973-014-3898-9. [5] Priyadharshini, A., & Kalainathan, S. (2016). Structural, optical, electrical properties of new hybrid organic–inorganic NLO single crystal: bis (1H-benzotriazole) hexaaqua-zinc bis (sulfate) tetrahydrate (BZS). Journal of Materials Science: Materials in Electronics, 1-13. DOI: 10.1007/s10854-016-6222-6. Cite the paper A. Priyadharshini, S.Kalainathan (2017). Bulk Crystal growth and Characterization of Organic Nonlinear Optical Crystal: 2-(2,4-dimethoxybenzylidene) malononitrile (DMM). Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.56.31.690

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Growth and Etching Studies of Cadmium Mercury Thiocyanate Single Crystals Grown by Gel Technique 39 P. Nisha Santhakumari1, S. Kalainathan2, a 1 – Department of Physics, Auxilium College, Vellore, India 2 – Centre for Crystal Growth, School of Advanced Sciences, VIT University, Vellore, Tamil Nadu, India a – skalainathan@gmail.com DOI 10.2412/mmse.94.21.874 provided by Seo4U.link

Keywords: diffusion, X-ray diffraction, crystal structure, second harmonic generation.

ABSTRACT. Single crystals of Cadmium mercury thiocyanate CdHg(SCN)4, a bimetallic thiocyanate complex material have been grown in silica gel using gel technique by the process of diffusion. Colourless transparent crystals of size 10mm x 3.1mm x 3.2mm have been obtained. The grown crystals were subjected to single crystal X-ray diffraction and high resolution X- ray diffraction studies. The crystal structure belongs to tetragonal system. Etching studies were made on the grown crystal to analyze the structural imperfection of the crystal. The Second harmonic generation efficiency of the grown crystal has been determined using Kurtz powder technique in comparison with Urea. Its efficiency is found to be 6.2 times greater than that of Urea.

Introduction. Recent studies show that bimetallic thiocyanate complexes of type AB(SCN) 4 exhibit excellent nonlinear optical properties. Zinc mercury thiocyanate (ZMTC), cadmium mercury thiocyanate (CMTC), zinc cadmium thiocyanate (ZCTC) and manganese mercury thiocyanate (MMTC) are some of the crystals belonging to this category. ZMTC and CMTC are found to have all the good characteristics such as crystallizing in a noncentrosymmetric space group I 4 , colourless and high thermal stability 1. ZMTC and CMTC are excellent nonlinear materials capable of second harmonic generation of Nd: YAG laser radiation of wavelength 1064 nm. Intracavity frequency doubling of a 946 nm Nd: YAG laser with CMTC crystal was reported by Changqiang Wang et al. [2] and generation of blue-violet light at room temperature with GaAlAs diode laser was reported by Yuan et al. [3]. These crystals cannot be grown from melt as they undergo decomposition before melting and can be obtained only from solution. Some of the doped crystals of the bimetallic thiocyanate complexes are also found to exhibit excellent nonlinear optical properties [4]. CMTC single crystals of considerably large size nave been obtained from silica gel in our laboratory. Growth procedure. Single diffusion technique and analytical grade reagents of mercury (II) chloride, ammonium thiocyanate and cadmium chloride were used for the growth CMTC single crystals in silica gel. Mercury (II) chloride and ammonium thiocyanate together were taken as the inner reagent and cadmium chloride was used as the outer reagent. Stock solution of sodium meta silicate was prepared by adding 244 grams of sodium meta silicate (Na 2SiO3 9H2O) to 500 ml of distilled water. Stock solution (7.5 ml) was diluted with equal quantity of distilled water (7.5 ml) and then its pH was adjusted to 3.4 using ExcelaR grade glacial acetic acid of purity 99.8. This stock solution of pH 3.4 was mixed with a mixture of 32 ml aqueous solution of 0.2M HgCl 2 and 16 ml aqueous solution of 4M NH4SCN and then allowed to gel in test tubes of length 15 cm and diameter 1.5 cm. After gelation, it was left as such for 48 hours for gel ageing and then the outer reagent, which is a mixture of 90% aqueous solution of 3M CdCl2, was added on to the top of the gel using a pipette. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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The outer reagent diffused in to the gel medium and due to its reaction with the inner reagent, crystals started growing. The harvested pure CMTC crystals are colorless. The experiment was carried out at an ambient temperature of about 30C. Fig. 1 shows the photograph of CMTC single crystals inside and outside the gel medium respectively.

Fig. 1. CMTC Crystal. Characterizations. The characterizations carried out for the gel-grown pure and Mn doped CMTC single crystals are briefly described below.The powder X-ray diffractometry analysis was performed with a graphite monochromated CuKα radiation of wavelength 1.5418 Å. Single crystal X-ray diffraction analysis was performed on ENRAF NONIUS FR590 diffractometer with Mo K radiation of wave length 0.7170 Å. The crystalline perfection of the grown crystal was analyzed with a multicrystal X-ray diffractometer developed at National Physical Laboratory (NPL). Etching studies were made on the grown crystal to analyze the structural imperfection of the crystal. Results and Discussion. X-ray diffraction analysis. The powder X-ray diffraction pattern of CMTC crystals are shown in Fig. 2. The diffraction planes are identified and indexed. Single crystal X-ray diffraction study was performed using ENRAF NONIUS FR590 diffractometer with Mo Kα radiation of wavelength 0.7170 A◦ to confirm the crystallographic system. The crystal structure is found to be tetragonal with the lattice parameters as a=b=11.473 A◦, c=4.250 A◦, α=β=γ = 90◦ and V=549A◦3 [5]. X-ray rocking curve studies. The specimen surfaces were lapped and polished and then chemically etched by a non-preferential chemical mixed with water and acetone in 1:2 ratios before recording the diffraction curves. Fig. 3 shows the high-resolution diffraction curves recorded for (2 0 2) plane with a multicrystal X-ray diffractometer in symmetrical Bragg geometry. The diffraction curve recorded contains two additional peaks which are 16 and 37 arc sec away from the main peak. These two additional peaks correspond to two internal structural very low angle (tilt angle  1 arc min) boundaries [6] whose tilt angles (misorientation angle between the two crystalline regions on both sides of the structural grain boundary) are 16 and 21 arc sec from their adjoining regions. The FWHM (full width at half maximum) of the main peak and the low angle boundaries are respectively 20, 17 and 21 arc sec. Though the specimen contains very low angle boundaries, the relatively low angular spread of around 150 arc sec of the diffraction curve and the low FWHM values show that the crystalline perfection is quite good.

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HRXRD analysis pure CMTC

Fig. 2. X-ray rocking curve recorded on the grown sample. Etching studies. The surface photograph of the CMTC crystal before etching and the etch patterns produced in the (0 1 1) plane of the crystal are shown in the figure. Etching study was carried out for different timings 5s, 10s and 15s using ethanol as etching agent. It is observed clearly that the etch pit formed in the surface is rectangular in shape. When the etching time is 5sec, many small rectangular shaped etch pits were formed in the crystal. As the etching time increases there is no change in the shape; but the size of the etch pattern was found to be decreased; there is an enormous increase in the etch pit density which suggests that the etch pits are due to dislocations.

(a)

(b)

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(c )

(d)

(e) Fig. 3. (a) Surface of the as grown CMTC crystal (b) Etch pattern produced for 5s (c) 10s (d) 15s (e) 20s. Powder Kurtz method. A preliminary study on the second harmonic generation efficiency of the crystal was carried out by Powder Kurtz method. In this experiment Q-switched pulses were obtained from a Q-switched Nd-YAG laser and urea was used as a reference material. Using an incident beam of power 5 mJ/ P, SHG signal of intensity 930 mV was recorded for our sample while that for urea was 150 mV. Its second harmonic generation efficiency is found to be 6.2 times greater than that of urea. Summary. CMTC single crystals can be obtained from silica gel using gel technique by the process of diffusion in an acidic medium. It belongs to tetragonal system. The crystalline perfection is reasonably good. Etching studies reveals the presence of dislocation.Its second harmonic generation efficiency is found to be greater than that of urea. References 1 X.Q.Wang et al. Spectroscopic and thermal behavior of ZnHg(SCN) 4, Materials Research Bulletin 37 (2002) 1859-1871, Article in Materials Research Bulletin 37(11):1859-1871 · September 2002 DOI: 10.1016/S0025-5408(02)00859-0 [2] Changqiang Q. Wang, Y.T.Chow, W.A.Gambling, Duorong Yuan, Dong Xu, Guanghui Zhang, Mingguo Liu, Minhua Jiang, Optics &Laser Technology 30 (1998) 291-293. MMSE Journal. Open Access www.mmse.xyz

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[3] D.R.Yuan, M.G.Liu, D.Xu, Q.Fang, W.T.Yu, W.B.Hou, Y.H.Bing, S.Y.Sun, M.H.Jiang, Appl. Phys. Lett. 70 (1997) 544. [4] G.P.Joseph, I.Korah, K.Raja Rajan, P.C.Thomas, M.Vimalan, J.Madhavan and P.Sagayaraj, Cryst. Res.Technol. 42, No.3, (2007) 295-299. [5] P Nisha Santha kumari, M.Margaret Beatrice, S. Kalainathan. A comparative study of pure and potassium doped cadmium mercury thiocyanate single crystal grown in silica gel Cryst Res Technol, ( 2009) 44, 177-183. [6] G. Bhagavannarayana, R.V. Ananthamurthy, G.C. Budakoti, B. Kumar and K.S.Bartwal, J. Appl. Cryst. 38, (2005) 768-771. Cite the paper P. Nisha Santhakumari, S. Kalainathan (2017). Growth and Etching Studies of Cadmium Mercury Thiocyanate Single Crystals Grown by Gel Technique. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.94.21.874

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Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties40 S. Karthick1 a, A. Albert Irudayaraj1, A. Dhayal Raj1, R. Vinayagamoorthy1 1 – PG and Research Department of Physics, Sacred Heart College, Tirupattur, Vellore Dist., India a – s.karthick5583@gmail.com DOI 10.2412/mmse.66.68.799 provided by Seo4U.link

Keywords: organometallic crystal, FTIR, UV-Vis, TG/DTA, NLO.

ABSTRACT. Cadmium Dimethyl Sulfoxide Thiocyanate (CDST) organometallic crystal was grown from aqueous solution. The grown CDST crystals are characterized by single X-ray diffraction for structural analysis. Fourier Transformation Infrared analysis confirms the presence of functional groups in the CDST. UV- Visible analysis reveals that CDST is about 90% transparent in the entire visible region and UV lower cutoff wavelength is 236 nm. TGA and DTA studies reveal the physicochemical stability of the CDST and NLO study by Kurtz – Perry powder technique reveals that the CDST exhibits emission of green light and the second harmonic generation efficiency of CDTS was 1.2 times that of KDP.

Introduction. Nonlinear optical frequency conversion materials play a vital role in optical communication, optical data storage and laser technology. Most of organometallic materials are suitable for nonlinear optical application due to better physical stability and second harmonic generation efficiency. Bimetallic Thiocyanate derivative crystals such Zinc Cadmium Thiocyanate (ZCTC) [1], Zinc Mercury Thiocyanate (ZMTC) [2], Cadmium Mercury Thiocyanate (CMTC) [3], Manganese Mercury Thiocyanate (MMTC) [4], etc., have been reported as dynamic Second Order Nonlinear Optical (SONLO) Materials. Some of Lewis base adducts thiocyanate derivative crystals such as Cadmium Mercury Thiocyanate dimethyl Sulfoxide (CMTD) [5], Cadmium Mercury Thiocyanate glycol mono methyl ether (CMTG) [6], Manganese Mercury Thiocyanate dimethyl Sulfoxide (MMTD) [7], Manganese Mercury Thiocyanate glycol mono methyl ether (MMTG) [8], etc., have been reported that large growth rate and better Nonlinear efficient but the thermal stability is decrease compared to the their bimetallic thiocyanate derivative crystals. Metal organic crystals such as bis-thiourea cadmium chloride, Allylthiourea cadmium chloride, tris (thiourea) zinc Sulphate, Ammonium (18- crown-6-ether) Cadmium Tri thiocyanate, etc., have been reported with good Nonlinear optical properties and moderate physical stability. X.Q. Wang et al., grown the bis (dimethyl sulfoxide) cadmium thiocyanate by temperature lowering method and characterized by Single crystal XRD, FTIR, UV-Visible and thermal analysis [9]. In the present work, Cadmium Dimethyl Sulfoxide Thiocyanate (CDST) organometallic crystal was grown by solvent evaporation method using water-DMOS has a mixed solvent. Structural, optical and thermal properties are reported and discussed. Synthesis and cystal growth of CDST. Commercially available AR grade chemicals were used as the stating materials. The synthesis of the Cadmium Dimethyl Sulfoxide Thiocyanate (CDST) was carried out by carefully incorporating the stoichiometric amount of Cadmium chloride, Potassium Thiocyanate and Dimethyl Sulfoxide in appropriate ratio using the chemical reaction give below:

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2đ??žđ?&#x2018;&#x2020;đ??śđ?&#x2018; + đ??śđ?&#x2018;&#x2018;đ??śđ?&#x2018;&#x2122;2 + 2đ??ś2đ??ť6đ?&#x2018;&#x2020;đ?&#x2018;&#x201A; ď&#x192; đ??śđ?&#x2018;&#x2018; (đ?&#x2018;&#x2020;đ??śđ?&#x2018; )2(đ??ś2đ??ť6đ?&#x2018;&#x2020;đ?&#x2018;&#x201A;)2 Pale red solution was kept undisturbed at room temperature. White precipitated of CDST was separated from the bottom of the solution. The saturated solution of CDST was prepared and kept for solvent evaporation at room temperature. Good transparent crystals were grown in the period of three weeks. To ensure the purity, recrystallization was carried out twice. The as grown harvested CDST crystals are shown in the fig. 1. Characterizations. The grown CDST crystals had been subjected to single crystal X-ray diffraction analysis was carried out using RIGAKU with SATRUN 724 plus detector and molybedeum as source at room temperature to confirm the crystallographic system. Fourier transformation infrared analysis was carried out using PERKIN ELMER FTIR spectrum II spectrometer using KBr pellet to confirm the presence of various functional groups of CDST. UV â&#x20AC;&#x201C; Visible analysis was carried out using Varian Cary 50 Bio UV â&#x20AC;&#x201C; Vis spectrophotometer to confirm optical energy gap. TG/DT analysis was carried out using NETZSCH STA 409C thermal analyzer to reveal the thermal stability of CDST. Nonlinear optical property of the powder CDST crystal was estimated by Kurtz â&#x20AC;&#x201C; perry powder technique using Q-switched Nd:YAG laser of wavelength 1064nm and Second Harmonic Generation efficiency is compared with KDP.

Fig. 1. As-grown crystal of CDST.

Single crystal X-ray diffraction analysis. The grown good quality CDST crystal was selected for the single crystal X-ray diffraction analysis. The result of CDST reveals that, it is belongs to Triclinic system with space group P1 which is recognized as noncentrosymmetric, thus satisfying one the basic and essential material requirements for the SHG activity of the crystal. The lattice Parameters of CDST crystal are, a= 5.9115 Ă&#x2026;, b= 8.053 Ă&#x2026;, c= 8.133 Ă&#x2026;, Îą = 114.371Ë&#x161;, Î˛ = 100.58Ë&#x161; and Îł =95.661Ë&#x161;. This result coincides with early reported of X.Q. Wang et al., [9]. Fourier transformation infrared analysis. When infrared radiation interacts with a sample, a portion of the incident radiation is absorbed at a specific wavelength and the FTIR absorption spectrum is to confirm of the presence of the functional group of the sample. The FTIR spectrum of the CDST was shown in the Figure 2. The vibrational peaks at 3008 and 1403 cm-1 is due to C-H symmetric stretching presence in DMOS. The peak at 2101cm-1 is due to C-N asymmetric stretching vibration which is presence in thiocyanate molecule. The peaks appear at 1314 and 1000cm-1 is due SCN rocking, which confirms the presences of thiocyanate. The peak 957 cm-1 is due S-O stretching vibration. The absorption occurs at 770 and 709 cm-1 is due C-S deformation. The peaks at 467 and 412 cm-1 due to presence of S-Câ&#x2030;ĄN bend of thiocyanate. MMSE Journal. Open Access www.mmse.xyz

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467 412

770 1403

709

1314

3008

957

2101

20 4000

3500

1000

% TRANSMITTANCE

3000 2500 2000 1500 -1 WAVENUMBER (cm )

1000

500

Fig. 2. FTIR spectrum of CDST. UV-visible analysis. For optical applications, especially for SHG the material considered must be transparent in the wavelength region of applicant. UV-Visible spectrum of CDST was shown in the figure 3. For the CDST, UV-Visible spectral was recorded the region 200 to 800 nm. The result reveals that the CDST is transparent about 90% in the entire visible region. The lower cutoff wavelength of CDST is found to be 236nm and optical band gap of the material is 5.3 eV.

% TRANSMITTANCE

100

236 nm 0 200

300

400

500

600

700

800

WAVELENGTH (nm)

Fig. 3. UV-Visible Spectrum of CDST. Second harmonic generation measurement. The grown crystal of CDST was powdered to a uniform particle size and then packed in a micro-capillary of uniform bore and exposed to Nd:YAG laser radiations. The generation of the second harmonic was confirmed by the emission of green light. The second harmonic generation (SHG) output power from CDST is found to be about 7.2 mV for

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the input energy of 1.2 mJ /pulse. The SHG output power from KDP is found to be 6 mV. The SHG efficiency of the CDST is 1.2 that of KDP. Thermal analysis. The good quality crystal of CDST was powdered and taken in the definite amount, to study the thermal property of the CDST material. The TG/DTA curves were shown in the figure 4. From TGA curve, it reveals that the first weight loss of 10% at 85°C due to water evaporation which was absorbed by sample from the atmosphere. There after no weight loss was founded up to 150° C, after that sudden weight loss of 65% was founded. Which indicate that the CDST was suitable up to 150°C. In DTA curve, a exothermic and a endothermic peak was founded. The board exothermic peak at 85°C due to water evaporation from the sample. The sharp endothermic peak at 168 °C indicated the melting point of the material.

100 0

150 C

-5

-10

DTA (V)

WEIGHT LOSS %

-15

168 C 20

-20

100

150

200

250

300

350

400

TEMPERATURE(C)

Fig. 4. TG/DTA curve of CDST.

Summary. Cadmium Dimethyl Sulfoxide Thiocyanate was successful synthesis in stoichiometric ratio. Cadmium Dimethyl Sulfoxide Thiocyanate crystal was grown by slow evaporation method. Single crystal XRD analysis reveals that CDST crystal belongs to Triclinic system with space group P1. The FTIR analysis confirms that presence on functional groups in CDST. UV-Visible analysis reveals that CDST is transparent about 90% in the entire visible region and optical energy band gap of 5.3 eV. The second harmonic generation efficiency of the CDST is 1.2 that of KDP. The TG/DTA reveals that CDST is thermally stable up to 168°C. CDST crystal has wide range transparent region, moderate thermal property and better second harmonic generation efficiency, which are essential properties need for optical communication and fabrication of optical storage devices. Refernces [1] Xinqiang Wang, Dong Xu, Mengkai Lu, Dourong Yuan, Guanghui Zhang, Shouxi Xu, Shiyi Guo, Xuening Jiang, Jiurong Liu, Chunfeng Song, Quan Ren, Ji Huang, Yupeng Tian., 2001, Growth and properties of UV nonlinear optical crystal ZnCd(SCN)4, Materials Research Bulletin vol. 36, 1287– 1299, S0025-5408(01)00598-0. [2] K. Ambujam, S. Selvakumar, Ginson P. Joseph, I. Vetha Potheher, P. Sagayaraj, 2007, Thermal, Optical, and Electrical Properties of Gel Grown ZMTC, Materials and Manufacturing Processes, vol. 22, 351–356, 10.1080/10426910701190766. MMSE Journal. Open Access www.mmse.xyz

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[3] P. Paramasivam, C. Ramachandra Raja, 2011, Synthesis, growth and characterization of cadmium manganese thiocyanate (CMTC) crystal, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 79, 1109–1111, 10.1016/j.saa.2011.04.028. [4] M. Manikandan, G. Vijaya Prasath, G. Bhagavannarayan, N. Vijayan , T. Mahalingam , G. Ravi, 2012, Structural, spectral and mechanical studies of bimetallic crystal: cadmium manganese thiocyanate single crystals , Applied Physics A materials science and processing vol. 108, 1015–1020, 10.1007/s00339-012-7015-2. [5] ShiyiGuo, DuorongYuan, DongXu, GuanghuiZhang, SuoyingSun, FanqingMeng, Xinqiang Wang, XueningJiang, MinhuaJiang, 2000, Growth of Cadmium Mercury Thiocyanate Dimethyl – Sulfoxides in Gel Crystal For Laser Frequency Doubling, Progress in Crystal Growth and Characterization of Materials, 75-79,S0960-8974(00)00019-X. [6] S. Cynthi, B. Milton Boaz, 2013, Synthesis and characterization of a novel non-linear optical crystal Cadmium mercury thiocyanate glycol mono methyl ether, International Journal of Engineering Science Invention, vol.2, 38-43. [7] X.Q. Wanga, D. Xua, M.K. Lua, D.R. Yuana, S.X. Xub, S.Y. Guoa, G.H. Zhanga, J.R. Liua, 2001, Crystal growth and characterization of a novel organometallic nonlinear-optical crystal: MnHg(SCN)4(C2H6OS)2, Journal of Crystal Growth, 224, 284–293, S 0 0 2 2 - 0 2 4 8 ( 0 1 ) 0 1 0 1 2 – 0. [8] Ginson P. Joseph, N. Melikechi, Jacob Philip, J. Madhavan, P. Sagayaraj, 2009, Studies on the electrical, linear and nonlinear optical properties of Manganese mercury thiocyanate bis(dimethyl Sulfoxide) an efficient NLO crystal, Physica B , vol.404, 295–299, 10.1016/j.physb.2008.10.055. [9] X.Q. Wanga, D. Xu, D.R. Yuan, M.K. Lu, X.F. Cheng, J. Huang, G.W. Lu, S.Y. Guo, G.H. Zhang, 2002, Growth, spectroscopic and thermal behavior of Cd(SCN)2(DMSO)2, Journal of Crystal Growth , vol. 246, 155–160, S0022 - 0248(02)01763 – 3. Cite the paper S. Karthick, A. Albert Irudayaraj, A. Dhayal Raj, R. Vinayagamoorthy (2017). Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.66.68.799

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Laser Hardening and Pack Boriding of EN 8D Steel41 K. Monisha1, P. Selvamuthumari1, D. Narendran1, Rasik Ahmad Parray1, J. Senthilselvan1,a 1 – Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-25, Tamil Nadu, India a – jsselvan@hotmail.com DOI 10.2412/mmse.13.65.82 provided by Seo4U.link

Keywords: pack boriding, laser hardening, surface modification, hardness.

ABSTRACT. This work is composed of two different techniques, laser hardening using HPDL and conventional pack boriding of EN 8D steel to improve the mechanical properties. The α-Fe phase observed in the XRD pattern of untreated EN 8D transformed to martensite and cementite phases due to the effect of laser irradiation, which is evidenced from the microstructure analysis. The martensite phase in the laser hardened sample results in improved hardness with maximum of about 825 HV0.2. In case of pack boriding, the sample was packed with boriding agent and sealed in a stainless steel container at 950°C for 6 hours. XRD pattern reveals the Fe2B peaks, which confirms the formation of borided layer at the sample surface. The hardness value in the tooth like borided layer is increased from 261 HV to 1193 HV due to this Fe2B phase.

Introduction. Iron-Carbon alloys are the most versatile, economical and globally utilized materials for industrial constructions and engineering systems. Depending on iron and carbon distribution, the microstructures get modified leading to miscellaneous mechanical properties [1]. Hypo-eutectoid steels with carbon concentration less than 0.8 wt% is composed of pearlite microstructure in untreated condition. The lamellar cementite distributed in the ferrite matrix does not possess superior surface properties for industrial and engineering applications [2]. Redistribution of the carbon and iron accordingly modifies the surface properties. Subjecting to heat treatment and customizing the process parameters favors the surface property modification. In Iron-Carbon steels, the martensite microstructures with fine needles exhibits high hardness and high wear resistance property. Fe-C phase diagram [3] gives the relationship between carbon composition and the processing temperature. Hypo-eutectoid steels [2, 4] when heated above 800°C (A3 transformation temperature), it completely transforms into γ-austenite. The fcc-austenite favors the solubility of carbon atoms into ferrite matrix than bcc-ferrite. On subsequent cooling, the carbon do not have sufficient time to form cementite and hence thin carbon needle starts to grow from the grain boundaries of austenite phase resulting in highly strained bct lath martensite which is responsible for high hardness [5]. Laser hardening [2] rapidly heats the material to several thousand degrees followed by rapid quenching in a fraction of seconds. During laser irradiation, the surface temperature shoots above the austenizing temperature and melts the substrate. Resolidification results in extremely high hardness as the cooling rate of laser hardening is more rapid than conventional hardening due to self quenching by the substrate. Boriding is a thermo-chemical process [6] where the substrate pre-coated with boriding agent and heated above the austeninzing temperature in conventional furnace. Boron being the hardest material, when diffused in ferrite matrix incorporates its high hardness property with the ductility of iron by © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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forming Fe-B composite. From Fe-B phase diagram [7] it can be interpreted that, above 700 °C the boron species in the boriding agent diffuses into the γ- ferrite matrix with the formation of Fe2B composite. Harder FeB composite can be obtained when 50% of the ferrite matrix is occupied by Boron [6, 7]. The composite layer formed depends on the percentage of boron species available in the boriding agent. Though FeB is harder than Fe2B composite, it is not widely preferred due to its brittleness. In this report, EN-8D steel discs were chosen for laser hardening and conventional pack boriding. Laser hardening was carried out using high power diode laser with 4 mm beam width at three laser powers 1.5, 1.7 and 2 kW with various scanning rate. In case of pack boriding, the sample was packed with boriding agent composed of Boropak powder at 50 wt% (source), KBF4 at 20 wt% (activator) and SiC at 30 wt% (filler) and sealed in a stainless steel container at 950 °C for 6 hours. Experimental Technique. EN 8D steels were hardened using high power diode laser with Gaussian beam mode. The case depth and hardness was controlled by optimizing the processing parameters such as laser beam power, scan rate and beam size. The laser beam was fixed at 1.5, 1.7 and 2kW with the scanning speeds of 400, 600, 800 mm/min and sufficient number of experimental trials were done. For pack boriding, the steel disc was packed inside the indigenously designed boriding chamber. The mentioned composition of boriding agents on all the sides followed by a layer of glass wool was packed in a stainless steel container. The container was placed in conventional box furnace directly at 950 °C with soaking time of 6 hours. The sample is then water quenched to restrict the diffusion of boron through the substrate resulting in localized high hardness on the surface. Results. Microstructure of the untreated, laser hardened and borided teeths are shown in fig. 2. The untreated substrate exhibits larger alternate ferrite and cementite grains representing the pearlitic microstructure. During laser irradiation, the carbon dissolves into the ferrite melt pool. Rapid solidification due to self quenching restricts the diffusion of carbon on cooling[8]. Due to this constrain, the carbide diffuses into austenite from the lateral side of the pearlite, resulting in needle shaped martensite structure [2].

(a)

(b)

(c)

Fig. 1. Microstructure of the (a) untreated, (b) laser hardened and (c) borided teeths. The pre-placed boriding agent, when heated above austenite transformation temperature, the boriding agent dissociates and diffuses the boron species into the substrate. The presence of ferrite and carbide atoms opposes the diffusion of boron through the substrate [3] resulting in tooth like microstructure corresponding to the growth of single Fe2B layer on the surface (Fig.1c) [6]. Further growth of FeB layer is not favored by the processing conditions, which may be due to the lack of boron species in the agent. XRD pattern of untreated, laser hardened and borided EN 8D steel is shown in Fig. 2. The XRD of untreated substrate confirms the presence of α-Fe phase. On laser hardened surface the formation of laser transformed martensite and cementite phases are confirmed which are in the body centered MMSE Journal. Open Access www.mmse.xyz

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tertragonal and orthorhombic structures, respectively [9]. During laser heating, the surface of the steel attains austenite temperature and on self-quenching it gets transformed into martensite. The formation of cementite phase may be due to delayed quenching by the effect of slow scan rate. The XRD pattern for borided EN 8D steel confirms the formation of the Fe2B layer (JCPDS number 75-1062) which is also evidenced by the tooth like microstructure observation.

(b)

(a)

Fig. 2. XRD pattern of (a) untreated and laser hardened and (b) Borided EN 8D steel. Fig.3 shows the hardness measured at different depths of the laser hardened cross sections using vicker’s microhardness tester at 200g load with dwell time of 3 secs. After laser hardening, hardness value increases from 178 HV to 825 HV, which is 5 times harder than the base metal. Higher hardness is achieved due to martensite phase formation by rapid heating and cooling [8]. The maximum case depth of 1200 µm was achieved. The hardness of the borided sample is measured to be 1193 HV due to the formation of Fe2B phase on the surface [6], evidenced from microstructure and XRD analysis. For 200g load AISI1040 Power 2000 W

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Fig. 3. (a) Hardness profile of laser hardened sample and (b) indentation mark on borided surface. Summary. The effect of high power diode laser surface hardening and pack boriding of EN 8D steel were studied. The laser heating process transformed the base metal α-Fe ferrite microstructure to high hardened martensite phase in a fraction of second, where as boriding heat treatment take a quite longer processing duration of 5 to 10 hours. The surface hardness of laser treated EN 8D steel increases from 178 HV to about 825 HV, with increased case depth of 1 mm. Five-fold increase in hardness was obtained by laser hardening technique. Pack boriding results in extreme high hardness of about 1193 MMSE Journal. Open Access www.mmse.xyz

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HV with the borided layer thickness of 25 µm. Hence laser treatment gives better result compared to conventional boriding treatment. References [1] V.L. de la Concepción, H.N. Lorusso, H.G. Svoboda, Effect of Carbon Content on Microstructure and Mechanical Properties of Dual Phase Steels, Procedia Materials Science, 2015. http://dx.doi.org/10.1016/j.mspro.2015.04.167 [2] L. Orazi, A. Fortunato, G. Cuccolini, G. Tani, An efficient model for laser surface hardening of hypo-eutectoid steels, Applied Surface Science, 2010. http://dx.doi.org/10.1016/j.apsusc. 2009.10.037 [3] H. Göhring, A. Leineweber, E.J. Mittemeijer, A thermodynamic model for non-stoichiometric cementite; the Fe–C phase diagram, Calphad, 2016. http://dx.doi.org/10.1016/j.calphad.2015.10.014 [4] M.F. Ashby, K.E. Easterling, The transformation hardening of steel surfaces by laser beams—I. Hypo-eutectoid steels, Acta Metallurgica, 1984. http://dx.doi.org/10.1016/0001-6160(84)90175-5 [5] P. Zhang, Y. Chen, W. Xiao, D. Ping, X. Zhao, Twin structure of the lath martensite in low carbon steel, Progress in Natural Science: Materials International, 2016. http://dx.doi.org/10.1016/j.pnsc.2016.03.004 [6] I.E. Campos-Silva, G.A. Rodríguez-Castro, 18 - Boriding to improve the mechanical properties and corrosion resistance of steels, in: Thermochemical Surface Engineering of Steels, Woodhead Publishing, Oxford, 2015, pp. 651-702. [7] M.-A. Van Ende, I.-H. Jung, Critical thermodynamic evaluation and optimization of the Fe–B, Fe–Nd, B–Nd and Nd–Fe–B systems, Journal of Alloys and Compounds, 2013. http://dx.doi.org/10.1016/j.jallcom.2012.08.127 [8] Y.K. Chuang, D. Reinisch, K. Schwerdtfeger, Kinetics of the diffusion controlled peritectic reaction during solidification of iron-carbon-alloys, Metallurgical Transactions A, 1975. 10.1007/BF02673703 [9] W.D. Callister Jr, Materials Science and Engineering: An Introduction, 7th ed., John Wiley & Sons, 2007. Cite the paper K. Monisha, P. Selvamuthumari, D. Narendran, Rasik Ahmad Parray, J. Senthilselvan (2017). Laser Hardening and Pack Boriding of EN 8D Steel, Vol 9. doi 10.2412/mmse.13.65.82

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Synthesis, Growth and Characterisation of New Organic Crystal: L-Histidinium 5 Sulfo Salicylate for Second Order Nonlinear Optical Applications 42 R. Usha1, N. Hema1, V. Revathi1, Ambika D. Shalini1, D. Jayalakshmi1, a 1 – PG and Research Department of Physics, Queen Mary’s College (A), Chennai-600 004, Tamilnadu, India a – djayalakshmi2016@gmail.com DOI 10.2412/mmse.92.96.883 provided by Seo4U.link

Keywords: monoclinic, FT-IR, UV and NLO.

ABSTRACT. L -Histinium 5 Sulfo Salicylate , an organic NLO crystal was grown for the first time by slow evaporation solution technique. Single crystal X ray diffraction analysis reveals that H5S belongs to monoclinic crystal system with non-centro symmetricspace group P21. The determined parameters are a=9.5707(17)A0, b= 19.038(4)A0, c= 8.315(2)A 0 ,β= 90.711(14) and V= 1514.8(6)A3. FT-IR and FT Raman studies were carried out to identify the functional groups prevent in H5S. Optical absorption study showed a UV cut off wavelength of 304 nm. The mechanical properties of the grown crystal has been analyzed by Vicker micro hardness method. The second harmonic generation was confirmed for LH5SS.

Introduction. Great efforts have been devoted to the research and design of highly efficient nonlinear optical (NLO) materials due to their widespread applications such as high-speed information processing, optical communications, and optical data storage [1) Amino acid is an organic compound that contains both amine and carboxyl functional groups and one can produce outstanding materials with the help of organic and inorganic counterparts. Amino acids are identified as potential candidates for the growth of single crystals combining with some organic acids which exhibits the most essential nonlinear optical (NLO)property for frequency conversion applications [2,3].Among the twenty amino acids, the most basic amino acid is l-histidine. Due to its basic nature, it forms a number of salts with different organic and inorganic acids which possess NLO properties. Some of the l-histidine compounds exhibit high second harmonic generation (SHG) conversion efficiency compared to the standard material KDP [4-10]. According to coordination chemistry, the ligand 5-sulfosalicylic acid (H3SSA) has three potential coordination groups: –COOH, –SO3H and –OH. Both –COOH and – SO3H are versatile coordinating groups and can coordinate with metal ions in a variety of modes [11], and there is a high possibility of proton transfer in organic salts, mainly N-heterocyclic, leading to tunable optical properties.The present investigation is on the growth of L-Histidinium 5 Sulfo Salicylate grown from slow evaporation method and on characterization of the grown crystal that is done using various techniques. Materials and methods. L-Histidinium 5 Sulfo Salicylate crystals were grown from an aqueous solution by slow evaporation technique. l-Histidine (99% pure) and 5 sulfosalicylic acid were taken in the stoichiometric ratio 1:1 and dissolved in double distilled water. The reaction is as follows, C6H9N3O2 + C7H6O6S

C13 H15 N3 O8 S

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The solution was filtered using whatmann filter paper and left undisturbed in a covered beaker. The growth condition was optimized and the grown crystals were further purified by successive recrystallization. Seed crystals of LH5SS were harvested after a span of 10 days. The photograph of the as grown crystal is shown in Fig. 1.

Fig. 1. Photograph of L-Histidinium 5 Sulfo Salicylate crystal. Results and discussion Single-crystal X-ray diffraction. The single-crystal XRD analysis of L Histidinium 5-Sulfo Salicylate (LH5SS) crystal was carried out using Bruker kappa APEX II single-crystal X-ray diffractometer with graphite monochromated MoKa radiation (k = 0.71073 A° ) at 293 K. A single crystal was selected for crystal structure determination. LH5SS crystallized in the monoclinic system within the non-centrosymmetric space group P21, its lattice parameters are: a = 9.5707(17) A ° , b = 19.038(4) A ° and c =8.315 (2) A ° and volume = 1514.8(6) Å3 FT-IR analysis. Infra red spectroscopy has been used to identify the functional groups and to determine the molecular structure of the synthesized compound. The FTIR analysis od LH5S was carried out between 4000 and 450 cm-1 using Perkin Elmer model spectrometer is shown in the fig.(1) The band observed at 3157cm_1 in spectra is due to the symmetric stretching of NH3+ group of Lhistidinium ion [12]. Most of the aromatic compound has some peaks in the region 3110 – 3000cm1 and they are being due to the stretching vibrations of the ring CH bonds. The peak observed at 3019cm-1 is assigned to the CH stretching vibrations. The -CH2- group of histidine produce peak at 2862.2 cm-1 due to its asymmetric stretching mode. The stretching vibrations of the C-C bond is identified in the peak 1619cm-1. [13]. The peaks at 1,477 and 925 cm-1 are due to S=O asymmetric stretching [14] and S–O as stretching of para-substituted sulfonic group (SO3H) in aromatic ring, respectively. The aromatic C–H in-plane bending vibration is observed at 1,161 cm-1. The peak at 836 cm-1 is due to C–H out-of-plane bending [15]. All these observations clearly demonstrate the formation of L Histidinium 5-sulfosalicylate single crystal. Frequency assignment of the absorption peaks are presented in Table 1. Table 1. FT-IR of the LH5SS crystal. Wavenumbers cm-1 3157 3030 2862 1475 1084 925

Assignments NH3 asymmetric stretching C-H stretching CH2 asymmetric stretching SO3 asymmetric stretching CO stretching of COO group S-O asymmetric stretching

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Fig. 2. FTIR spectrum of LH5SS. UV-Vis Spectral studies. The optical absorption plays an important role in identifying the potential of the NLO material. Materials having wide absorption window with reduced absorption around the fundamental and second harmonic NLO application. Optical absorption data were taken on this polished crystal sample of about 3mm thickness using Perkin elmer lamda 35 model spectrometer between 200 – 800nm. The spectrum indicates that the UV cut-off wavelength of LHPT occurs at 304 nm. The band gap is found to be 4.09eV. It is well known that the efficient NLO crystal has an optical transparency at lower cut-off wavelength between 200 and 400 nm [16]. Also, it is observed that there is no significant absorption in the entire visible region which reveals that it suitable for the optoelectronic devices 1.6

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Fig. 3. UV-Vis absorption spectrum of LH5SS. Photoluminescence studies. Photoluminescence (PL) measurement is a prominent tool for determining the crystalline quality of a system as well as its exciton fine structure [17]. Photoluminescence in solids is the phenomenon in which electronic states of solids are excited by light of particular energy and the excitation energy is released as light. The photon energies reflect the variety of energy states that are present in the material. The emission spectrum was recorded for the LH5SS crystal in the range of 304–800 nm and the sample was excited at 304 nm. The emission MMSE Journal. Open Access www.mmse.xyz

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spectrum (PL spectrum) and excitation spectrum are presented in the Fig 4. The PL spectrum of the LH5SS sample consists of two emission bands: strong UV peak at 613 nm shows the emission of red color and a broad band at 419 nm shows the emission of violet color. The additional peak at 419 nm may represents the defect level existed due to the presence of low angle grain boundaries. 7

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Fig. 4. Photoluminescence Spectrum. NLO property.The nonlinear optical property of the grown crystal was tested using Kurtz-Perry powder technique by passing a Q switched , mode locked Nd:YAG laser of 1064 nm and pulse width of 8 ns(spot radius of 1mm) on the powder sample of LH5SS. The input laser beam was passed through an IR reflector and then directed on micro crystalline powdered sample. Photodiode detector and oscilloscope assembly detected the green light emitted by the sample. The SHG efficiency was evaluated by taking the micro crystalline powder of KDP as the reference material. Input laser energy incident on the sample was 0.68J. The SHG efficiency LH5SS is 1.5 times greater than the KDP.Microhardness Measurement. Hardness is an important mechanical property required for the fabrication of electronic and optical devices. The LH5SS crystal placed on the platform of the microhardness tester and loads of different magnituges(10,25,50g) were applied over a fixed interval of time (10s). The hardness was calculated using the relation: Hv = (1.8544 P/d2) kg/mm2 where P is the applied load in kg and d is the average diagonal length of the indentation in mm. It is observed from the graph that the hardness value increases with the load increases.

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Fig. 5. Microhardness graph. Summary. Single crystals of LH5SS, an organic nonlinear optical material, were grown by slow evaporation method at room temperature. The single crystal XRD analysis confirms the grown crystal belongs to monoclinic system. The functional groups of the grown crystal were identified using FTIR spectrum. The optical transmittance study shows the crystal has good transmittance in the entire visible region and wide band gap. The Kurtz and Perry powder SHG method confirm the SHG efficiency of LH5SS is 1.5 times that of KDP and phase- matching property. The mechanical property of the material was studied by Vicker’s hardness measurement. References [1] P.N. Prasad, D.J. Williams, Introduction to Nonlinear Optical Effects in Organic Molecules and Polymers, Wiley, New York, 1991; (b) T. Pal, T. Kar, G. Bocelli, L. Rigi, Cryst. Growth Design 3 (2003) 13. [2] D. Xu, M. Jiang, Z. Tan, A new phase match able nonlinear optical crystal L-arginine phosphate monohydrate, Acta Chem. Sin. 41 (1983) 570–573. [3] G. Ramesh Kumar, S. Gokul Raj, R. Sankar, R. Mohan, S. Pandi, R. Jayavel, Growth,structural, optical and thermal studies of non-linear optical l-threonine singlecrystals, J. Cryst. Growth 267 (2004) 213–217 [4] B. Dhanalakshmi, S. Ponnusamy, C. Muthamizhchelvan, Growth and characterization of a solution grown, new organic crystal: l-histidine-4-nitrophenolate4- nitrophenol (LHPP), J. Crystal Growth 313 (2010) 30–36. [5] S.A. Martin Britto Dhas, J. Suresh, G. Bhagavannarayana, S. Natarajan, Growth and characterization of a new organic non-linear optical (NLO) material: lhistidinium trifluoroacetate, Open Cryst. J. 1 (2008) 46–50. [6] Madhavan, S. Aruna, K. Prabha, J. Packium Julius, Joseph Ginson P., S. Selvakumar, P. Sagayaraj, Growth and characterization of a novel NLO crystal l-histidine hydrofluoride dihydrate (LHHF), J. Crystal Growth 293 (2006)409–414. [7] S. Aruna, M. Vimalan, P.C. Thomas, K. Thamizharasan, K. Ambujam, J. Madhavan, P. Sagayaraj, Growth and characterization of semi organic nonlinear optical LHPCL crystals, Cryst. Res. Technol. 42 (2007) 180–185. [8] Anandan Pandurangan, Jayavel Ramasamy, Crystal growth and characterization of semi organic single crystals of l-histidine family for NLO applications, J.Crystal Growth 322 (2011) 69–73.

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[9] S.A. Martin Britto Dhas, S. Natarajan, Growth and characterization of two new NLO materials from the amino acid family: l-histidine nitrate and l-cysteine tartrate monohydrate, Opt. Commun. 281 (2008) 457–462. [10] K. Moovendarana, S.A. Martin Britto Dhasb, S. Natarajana Growth and characterization of lhistidinium 2-nitrobenzoate single crystals: A new NLO material. Optik 124 (2013) 3117– 3119 [11] J.F. Ma, J.Y. Li, G.L. Zheng, J.F. Liu, Inorg. Chem. Commun. 6,581 –583 (2003 [12] H.M. Albert ,J.JosephArulPragasam, G.Bhagavannarayana, C.Alosious Gon- sago, Investigation on structural ,spectral, and thermal properties of L-histidinium glutarate monohydrate(LHG), J.Therm.Anal.Calor.118(2014) 333–338. [13] Investigations on spectroscopic, optical, thermal and dielectric properties of a new NLO material: L –histidinium p- toluenesulfonate [LHPT] M. Suresh, S. Asath Bahadur and S. Athimoolam [14] P.U. Singare, R.S. Lokhande, R.S. Madyal, Open J. Phys. Chem.1, 45–54 (2011) [15]. V.K. Rastogi, M.A. Palafox, R.P. Tanwar, L. Mittal, Spectrochim. Acta A 58, 1989–1994 (2002) [16] Y. le Fur, R. Masse, M. Z. Cherkaoui, and J. F. Nicuod, Zeitschriftf¨ur Kristallographie 210 (1995) 856-860. [17] L. Kumari, W.Z. Li, Synthesis, structure and optical properties of zinc oxidehexagonal microprisms, Cryst. Res. Technol. 45 (3) (2010) 311–315. Cite the paper R. Usha, N. Hema, V. Revathi, Ambika D. Shalini, D. Jayalakshmi (2017). Synthesis, Growth and Characterisation of New Organic Crystal: L-Histidinium 5 Sulfo Salicylate for Second Order Nonlinear Optical Applications. Mechanics, Materials Science & Engineering, Vol 9. 10.2412/mmse.92.96.883

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Investigation on Zn (II) Doped Lithium Sulphate Monohydrate Single Crystals 43 E. Glitta Sumangali1, Girish M. Joshi2 1 – Department of Physics, VIT University, Vellore-632 014, Tamilnadu, India 2 – Material Physics Division, VIT University, Vellore-632 014, Tamilnadu, India DOI 10.2412/mmse.80.57.55 provided by Seo4U.link

Keywords: crystal growth, XRD technique, FTIR, optical studies, EDAX.

ABSTRACT. Zn-doped Lithium Sulphate monohydrate single crystals with good quality were grown by slow evaporation technique. The grown crystals were subjected to powder X-ray diffraction study that confirms the change in the lattice parameters and quality of the crystal, Fourier Transform Infrared Spectroscopy ensures the functional groups, UV-Visible analysis which reveals the optical transmittance, lower cut-off wavelength and band gap, and Energy dispersive X-ray analysis gives chemical composition and confirms the inclusion of the dopant into the grown pure LSMH single crystal.

Introduction. The investigation of NLO materials have gained predominant attention in current research owing to their applications in the technology of information transmission and processing. It is evident that the NLO crystals have exceptional technological requirements such as wide transparency range, fast response and high damage threshold. Due to such distinct optical properties, synthesis and growth of unique materials are in progress. The most widely used materials in photonic technologies are mainly inorganic crystals based on Borates and Phosphates. Lithium Sulphate Monohydrate Li2So4H2o (LSMH) is also one such inorganic highly NLO active materials [1-4]. The crystal structure and space group of Lithium Sulphate Monohydrate were originally determined as monoclinic point group P21 by G.E.Ziegler (1934) [5]. A detailed study on the redetermination, further refinement and inclusion of hydrogen’s position of Li2So4H2o structure were reported [6-8]. It is explored from the literature that the Lithium Sulphate Monohydrate has remarkable piezoelectric and electro-optic properties. Lithium Sulphate Monohydrate has highest pyroelectric effects among the non-ferroelectric polar crystals [9]. Earlier researches show that Lithium found to be effective NLO material on its combination with Selenate, Glycine and Bromide [10-12]. Since there is large demand for crystal in electronic industries, it is required to synthesize NLO material and to improve the properties of existing materials. Considering the facts, ethylene diamine tetra acetate and Cu II doped Lithium Sulphate Monohydrate single crystals have been synthesized and shown as promising candidate for optical second harmonic generation [13-14]. In the present work attempts have been made to enhance the physical properties of single crystals by incorporating bivalent metal dopant. The presence of very low concentration of suitable additives enhances crystalline perfection [14]. Therefore, we present the Synthesis of grown Lithium Sulphate monohydrate single crystals containing 0.1 mole percentage of Zinc Sulphate by slow evaporation method. The lattice parameters of doped crystals are evaluated by powder X-Ray diffraction study, Optical analysis and the presence of Zn has been determined by Energy dispersive X-ray analysis. Experimental. Single crystals of pure and Zinc doped Lithium Sulphate Monohydrate (LSMH) were grown at room temperature by the reaction between Lithium Sulphate Monohydrate and Zinc Sulphate and dissolving 0.9 mol % of Li2So4H2o (LSMH ) with 0.1 mol % of ZnSo 4 .7H2O in double © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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distilled water. The solution was continuously stirred well for long time using a magnetic stirrer to ensure homogenous solution. The completely dissolved solution was filtered using Wattman filter paper to remove the suspended impurities and allowed to yield crystalline by slow evaporation of solvent. The solution was allowed to evaporate at room temperature, tiny seeds were observed within 15 days and good quality pure and doped crystals were collected after 30 days. The grown pure and doped crystals are shown in fig.1 that posses already reported crystallography-dependent shape confirmed by chemical bonding theory of crystal growth [15].

Fig. 1. Photograph of pure LSMH crystal.

Fig. 2. Photograph of Zn doped LSMH crystal.

Characterization Techniques Powder X-Ray Diffraction. Powder X-ray diffraction study on doped LSMH crystal grown by slow evaporation technique was carried out. The crystalline nature and the lattice parameters were confirmed by powder XRD. Powder XRD pattern was recorded for the grown crystals using BRUKER and shown in fig.3. The results were compared with the JCPDS database [16] where the prominent peaks of the reported values coincided with the investigated patterns. The sharp and intense peak on the pattern indicates that the crystallities are pure and dislocations free [17].By using the observed 2θ and d values from the powder XRD pattern , the hkl indices and lattice parameters were calculated. The values are a=5.35131Å, b=4.87966 Å, c=8.04214 Å. It is apparent that the grown Zn doped crystal also has the monoclinic system, however, the incorporation of the metal ion in LSMH pronounced slight changes in the lattice parameters.

Fig. 3. XRD pattern of Zn-LSMH crystal. MMSE Journal. Open Access www.mmse.xyz

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FTIR Spectrum Analysis. The FTIR analysis of LSMH and ZnSo 4 doped LSMH were carried out between 400 cm-1-4000 cm-1 usinjg Perkin Elmer Spectrum II. The FTIR spectrum of LSMH and Zn doped LSMH was shown in fig.3. From the spectrum it is evident that peak values clearly shows that the presence of LSMH in grown crystals. From the spectrum the So 4- stretching bands are generally superimposed near 1114 cm-1. An intense sharp peak at 1613 cm-1 is due to the bending vibration mode of H2O. The sharp peak at 654 cm-1 indicates the presence of sulfate ion. The spectra show the presence of H2O molecule and O-H symmetric stretching at 3490 cm-1. FTIR assignments on the grown crystals were given in below table. Table 1. Wavelength and Assignments of LSMH and Zn-LSMH. Pure LSMH (cm-1)

Zn doped LSMH (cm-1)

Assignments

3490

3478

Presence of water molecule (O-H Symmetric Stretching)

1615

1613

Bending Vibration mode of H2O

1114

1098

Presence of Sulphate

654

â&#x20AC;&#x201C;

Presence of Sulphate ion

Fig. 4. FTIR spectrum of LSMH and Zn-LSMH crystals. UV-Visible Spectrum Analysis. UV-visible- NIR spectroscopic analysis is very important for any optical material because an optical material can be of practical use only if it has a wide transparency window. To record the transmission data Varian Cary 50 bio UV- visible- NIR spectrophotometer in the wavelength region150-1100 nm at ambient temperature with high accuracy was used. The recorded data was used to calculate the optical transparency, band gap of the grown crystals. The Transmission spectrum of LSMH and Zn doped LSMH as shown in fig.4. The cut off wavelength of pure LSMH was found to be 213 nm and Zn doped LSMH was found to be 249 nm. The bandgap of pure LSMH and Zn doped LSMH were found to be 5.8 eV and 4.9eV respectively.

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EDAX Analysis. Quantitative EDAX analysis is the most commonly used method for chemical analysis of materials. The elemental analysis was carried out using GENESIS 4000. The EDAX spectrum of Zn doped LSMH is displayed in Fig.5.which illustrates the characteristic peaks corresponding to the binding energy state of S, O and Zn. The incorporation of Zn in lithium sulphate monohydrate was confirmed in this analysis. It is to be mentioned here that lithium cannot be identified from the sample by EDAX method for the obvious reason that the X-ray fluorescence yield is extremely low for Li [18-19].

Fig. 5. UV Transmittance spectrum and of LSMH and Zn-LSMH crystals.

Fig. 6. EDAX spectrum of Zn doped LSMH single crystal. Summary. Single crystals of Zn doped lithium sulphate monohydrate has been grown by slow evaporation technique. Powder XRD study substantiate the crystal perfection with monoclinic crystal structure point group P21.FTIR spectrum confirms the functional groups of the grown crystals. The less optical absorption in the visible region and decreased band gap were studied. Using EDAX analysis presence of dopant was ensured. All these studies reveal that the presence of bivalent dopant enhances the crystal quality. References [1] Fang Kong, Shu-Ping, Zhong-Ming,Jiang-Gao Mao and Wen-Dan Cheng, A new type of secondorder NLO material, J.AM.CHEM.SOC, China, 2006, 128, 7750-7751. MMSE Journal. Open Access www.mmse.xyz

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[2] Mohd. Shkir, S. Alfaify, M. Ajmal Khan, Ernesto Dieguez and Josefina perles, Synthesis, growth of L-Proline lithium bromide monohydrate, J. Crystal growth, 2014, 391, 104-110. [3] Dongsheng Yuan, Zeliang Gao, Shaojun Zhang, Zhitai Jia, Jun Shu, Yang Li, Zhengping Wang, and Xutang Tao,Linear and nonlinear optical properties of terbium calcium oxyborate single crystals, Optics Express 27606, 2014 , 22, [4] R.Priya, S.Krishnan, C.Justin Raj and S.Jerome Das, Growth and characterization of NLO active lithium sulphate monohydrate single crystals, Cryst. Res. Technol.2009, 44 No.12,1272-1276. [5] G.E.Ziegler,the crystal structure of lithium sulphate mono-hydrate,New York university Bobst library,1934,456-461 [6] Allen. C. Larson and Helmholz, Redetermination of the crystal structure of Li2SO4H2O, J. Chem. Phys, 1954, 22, 2049-2050. [7] Allen C. Larson, The crystal structure of Li SO4. H2O a Three Dimensional Refinement, Acta Cryst, 1965, 18, 717-724. [8] H. G. Smith, S.W. Peterson and H. A Levy, Neutron diffraction study of Lithium sulfate Monohydrate, J. Chem. Phys, 1968, 48, 5561-5565. [9] P.Becker, S.Ahrweiler, P.Held, H.Schneeberger ,L.Bohaty Thermal expansion,pyroelectricity and linear optical properties of Li2SeO4.H2O and Li2SO4.H2O, Cryst. Res. Technol.2003, 38, 881-889. [10] Roger Frech and Enzo Cazzanelli, Vibrational study of selenate- Doped Lithium Sulfate: Single Crystals and Fused salts, Journal of solid state chemistry, 1988, 74, 256-259. [11] T.Balakrishnan and K.Ramamurthi Growth and characterization of glycine lithium sulphate single crystal, Cryst. Res. Technol.2006, 41 No.12,1184-1188. [12] S. SAthish Kumar, T. Balakrishnan, K. Ramamurthi and S. Thamothran, Synthesis , Structure, Crystal Structure and Characterization of L-proline lithium sulphate monohydrate, Spectrochimica Acta part A: Molecular and Bio molecular spectroscopy ,2014, 1-14. [13] R. Manimekalai, A.Puhal raj, and C. Ramachandra Raja Growth and characterization of Ethelene Diamine Tetra Acetate doped LSMH crystals, Optics nd Photonics Journal, 2012, 2, 216-221. [14] K.Boopathi, P.Ramasamy and G. Bhagavannarayana, Growth and characterization of Cu(II) doped negatively soluble lithium sulfate monohydrate crystals, J. Cryst. Growth, 2014, 386, 32-34. [15] L.Bohaty,P.Becker, H.JEichler,J.Hanuza,M.Maczka,KTakaichi,K.Ueda,A.A.Kaminskhi, Laser Physics 15 (2005)1509. [16] Howard E. Swanson, Marlene C. Morris, and Eloise H. Evans, Standard X-ray Diffraction Powder Patterns, National Bureau of Standards Monograph 25-Section 4, Issued June 28, 1966 [17] P.S. Latha Mageshwari, R.Priya, S.Krishnan, V.Joseph and S. Jerome Das, Optical, dielectric and ferroelectric behavior on doped lithium sulphate crystals, Optik, 2014, 1-6. [18] G.Emerson Robin, U.Sankar, T.Chithambarathanu, P. Selvarajan, International Journal of Innovative Research in Advanced Engineering (IJIRAE), 2 (2015) 195-199 [19] P. Rosaiah, O.M Hussain, Adv Matt. Lett. 4 (2013)288-295. Cite the paper E. Glitta Sumangali, Girish M. Joshi (2017). Investigation on Zn (II) Doped Lithium Sulphate Monohydrate Single Crystals. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.80.57.55

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Gel Growth: A Brief Review44 H.O. Jethva1 1 – Crystal Growth Laboratory, Physics Department, Saurashtra University, Rajkot, India DOI 10.2412/mmse.64.79.613 provided by Seo4U.link

Keywords: gel growth, silica hydro gel, tartrate crystals, biomaterials crystals.

ABSTRACT. Crystals are the pillars of the various applications in the field of science and technology. The advances in these fields depend upon the availability of good quality crystals. Therefore, efforts have been made on the development of crystal growth techniques. Gel growth technique is one of them. The present article is a brief review that deals with the growth of various types of crystals that can be grown by gel technique. Gel growth technique is quite simple and well suited for the crystal growth of compounds, which are sparingly soluble in water and decompose before melting. This technique can be set up in a laboratory with simple glass-wares and without any need of sophisticated instruments and high temperature furnaces. By carefully selecting the specific gravity of gel, pH and concentration of the reactants, good quality crystals can be grown at room temperature. Even today, the gel growth technique continuous to attract various researchers.

Introduction. Crystals grown in gel medium has attracted the attention of many researchers [1]. There is a good review article available on gel growth technique by Patel and Rao [2]. Gel is a two component system, semi-solid in nature, rich in liquid, stable in form, flexible and having fine pores through which diffusion takes place. It is produced by the interaction of a gel forming compound with the solvating medium. The characteristic properties of gel are that it contains high percentage of solvent and little solid matter. Gel forming substances and solvating solvents stabilize each other in the gel structure and it may lose its solvent content during drying. Gel can be classified in number of ways but silica hydro gel is the most favorite gel for the crystal growth experiments. Structure of silica hydro gel. When sodium meta-silicate goes into aqueous solution, mono-silicic acid is produced with the liberation of NaOH in accordance with the reaction Na 2SiO3 + 3H2O  H4SiO4 + 2NaOH. Mono-silicic acid can polymerize with the liberation of water.

This can occur repeatedly and a three dimensional network of Si-O links is established as silica hydrogel. Crystal growth by gel. To grow the crystals by gel method, generally, neutral gel like sodium metasilicate or agar is preferred as a growth medium. After preparing the gel solution of appropriate density, it is impregnated or set at desired pH by one of the reactant having proper molar concentration and then is poured into a test tube. After setting the gel, a supernatant solution having proper molar © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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concentration is poured gently on the set gel. Supernatant solution diffuses into gel and reacts with the other solution already present there. Then nucleation and growth of crystal start to occur. This technique may be thought as more-or-less similar to the growth of foetus in motherâ&#x20AC;&#x2122;s womb. Figure 1 shows the schematic diagram of this technique, while figure 2 shows grown crystals of pure lead tartrate, mixed lead cadmium tartrate and mixed lead cobalt tartrate in test tube.

Fig. 1. Schematic diagram.

Fig. 2. a) Pure Pb tartrate, b) mixed Pb-Cd tartrate, c) Pb-Co tartrate. Factors affecting the growth rate. To set the optimum conditions for growing crystals, it is important to set the different parameters such as, gel density, gel pH, concentration of reactants and supernatant, gel setting time, gel aging time, impurities in the solvent etc. Generally, the gel density may range from 1.03 to 1.08 g/cm3. It is observed that as the gel density increases, transparency as well as gelation time decreases, means gel set more rapidly. As the gel pH increases, transparency of the gel as well as number of crystals decreases. Further, the crystals may contaminate with the silica gel, which results into not well defined semi-transparent to opaque crystals.

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Increased concentration of reactants, for example, tartaric acid in case of growth of tartrate crystals, required more volume of SMS to set the required pH value. Further, the increased concentration provides more negative ions, i.e. tartrate ions, to combine with the positive ions of the supernatant solution. On the other hand, decreased concentration of supernatant, may result into few nucleation and small size of crystals. As the aging time of gel increased, the pore size and hence the rate of diffusion of ions into the gel reduced, which results into the reduction of number of crystals. After a very long time, the pore size reduced such that no nucleation is observed at all. Advantages. Gel is chemically inert and harmless. Crystal nuclei are delicately held in a position of their formation and growth. Damage of nuclei can be prevented due to impact with bottom or walls of the container. Crystals can be observed practically in all stages of their growth. By changing growth conditions, crystals having different morphologies and sizes can be obtained. It is very simple and inexpensive technique to grow good quality crystals. There is no need to use costly and sophisticated instruments and can be set up easily in small laboratories.To grow the crystals, simple test tubes and U-tubes can be used. By this technique, crystals of various tartrate, oxalates and carbonates, phosphates of various compounds and crystals of various biomaterials can be grown. This technique can also be used for simulation of crystal growth in various biological systems, for example, growth of kidney stones, growth of monosodium urate in the joints in case of arthritis, cholesterol crystals etc. Limitations. Crystal size is generally small. Hence, large crystals cannot be grown. Growth period is large. If gel itself is impure, there is a chance of crystals being impure or unsuitable. Gel grown crystals. Some pure and mixed gel grown crystals, which are sparingly soluble in water and grown in present author’s laboratory by various researchers are listed in the table 1 and table 2, respectively. Table 1. Pure tartrate crystals. Name of the crystal Calcium tartrate [3] Zinc tartrate [4]

Lead tartrate [5]

Manganese tartrate [6] Iron tartrate [6]

Gel parameters

Expected reaction

Density-1.06, pH-3.8, Reactant-1M tartaric acid solution. Supernatant solution-1M CaCl2 Density-1.04, pH-4.5, Reactant-1M tartaric acid solution. Supernatant solution-1M ZnCl2 Density-1.05, pH-5, Reactant-1M tartaric acid solution. Supernatant solution-1M (CH3CO2)2Pb·3H2O Density-1.04 to 1.06, pH-3.6 to 4, Reactant-1M tartaric acid solution. Supernatant solution-1M MnCl2 Density-1.04 to 1.06, pH-3.6 to 4, Reactant-1M tartaric acid solution. Supernatant solution-1M FeSO4

CaCl2 + H2C4H4O6 + nH2O → CaC4H4O6.nH2O + 2HCl ZnCl2 + H2C4H4O6 + nH2O → ZnC4H4O6.nH2O + 2HCl (CH3CO2)2Pb·3H2O + C4H6O6 → PbC4H4O6·3H2O + 2CH3COOH MnCl2 + H2C4H4O6 + nH2O → MnC4H4O6.nH2O + 2HCl FeSO4 + H2C4H4O6 + nH2O → FeC4H4O6.nH2O + H2SO4

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Table 2. Mixed tartrate crystals. Name of the crystal Iron-Manganese mixed tartrate [4]

Gel parameters

Expected reaction

Density-1.04 to 1.06, pH-3.6 to 4, Reactant-1M tartaric acid solution. Supernatant solution-1M MnCl2 and 1M FeSO4

(1-X) FeSO4(aq) + X MnCl2(aq) + H2C4H4O6 + nH2O = MnXFe(1-X)C4H4O6 nH2O + 2XHCl + (1-X)H2SO4 Where, X = 0.2, 0.4, 0.6 and 0.8. (1-X)Pb(NO3)2(aq) + XCd(NO3)2,4H2O(aq) + H2C4H4O6 + nH2O = CdXPb(1-X)C4H4O6 nH2O + 4HNO3 + 3H2O + 1/2O2 Where, X = 0.2, 0.4, 0.6 and 0.8. XMnCl2(aq) + (1-X)CuSO4(aq) + H2C4H4O6 + nH2O = MnXCu(1-X)C4H4O6.nH2O + 2XHC l + (1-X)H2SO4 Where, x = 0.2, 0.4, 0.6, and 0.8 CaCl2(aq) + CuCl2 + H2C4H4O6 + nH2O = CaCuC4H4O6 nH2O + 2HCl

Lead-cadmium mixed tartrate [7]

Density-1.05, pH-4.5, Reactant-1M tartaric acid solution. Supernatant solution-1M Pb(NO3)2 and 1M Cd(NO3)2 4H2O

Manganese-copper tartrate [8]

Density-1.04, pH-3.8, Reactant-1M tartaric acid solution. Supernatant solution-1M MnCl2 and 1M CuSO4

Cu+2 doped calcium tartrate tetrahydrate crystals [3] Iron-manganesecobalt tartrate [9]

Density-1.06, pH-3.8, Reactant-1M tartaric acid solution. Supernatant solution-1M CaCl2 and 0.1M CuCl2 Density-1.04, pH-3.8, Reactant-1M tartaric acid solution. Supernatant solution-1M MnCl2, 1M FeSO4 and 1M CoCl2

(1−X−Y) FeSO4(aq) + XMnCl2(aq) + YCoCl2(aq) + H2C4H4O6 → Fe(1−X−Y)MnXCoYC4H4O6 + 2(X+Y)HCl + (1−X−Y)H2SO4, Where X = 0.2, 0.6 and Y = 0.2, 0.6.

Some gel grown crystals, which creates human suffering are listed in the table 3. Inhibition and dissolution study of the urinary stone and cholesterol crystals is also possible by gel method. In in vitro studies, different herbal extracts of medicinal plants are used in the crystal growth experiments. The crystals are grown in the laboratory by mimicking the atmosphere of human body by gel growth method. In gel growth, these extracts are added on the top and the growth rate of crystals is observed. If the crystal length decreases then it is called dissolution, which can be used for treatment to cure the problem. If the crystal length increase becomes slow then it is inhibition, which can be used for treatment to give relief. Some well known herbal extracts, using which growth inhibition study was carried out by Chauhan et al [10] and Parekh et al [12] on Struvite crystals and Hydroxyapatite crystals, respectively in Author’s laboratory are Boerhaavia diffusa Linn (in Sanskrit Purnarnava), Routla Aquatica Lour (in Sanskrit Pashanabheda), Tribulus terrestris Linn (in Sanskrit Gokshuru), Commiphora wightii Engl (in Sanskrit Guggul), Boswellia serrta Roxb (in Sanskrit Salai Guggul) and Aerva lanata Juss ex. Schult (in Sanskrit Gorakshanganja/Kapur Madhura). The study showed remarkable decrease in apparent length of the Struvite crystals as well as reduction in the number of Liesegang rings and diffusion length of the Hydroxyapatite crystals in the presence of the different herbal extracts.

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Table 3. Urinary stone, cholesterol and arthritis crystals. Name of the crystal Struvite (MgNH4PO4 6H2O) or urinary stone crystals [10]

Cholesterol (a combination of steroid and alcohol) crystals [11]

Hydroxyapatite [Ca5(PO4)3(OH)] or arthritis crystals [12] Monosodium Urate Monohydrate (NaHC5H2N4O3) crystals in joints responsible for Gout [13] Brushite (CaHPO4 2H2O) or urinary type crystals [14]

Calcium oxalate (CaC2O4) crystals [15]

Gel parameters Density-1.04 to 1.08, pH-4.5 to 8, Reactant-0.5M ammonium dihydrogen phosphate. Supernatant solution-1M MgC4H4O64H2O Density-1.05, pH-5, Reactant-1M acetic acid solution. Supernatant solution-solution of cholesterol prepared in acetone with 1wt% concentration Density-1.06, pH-6 to 6.5, Reactant-1M ortho-phosphoric acid solution. Supernatant solution-1M CaCl2 Density-1.05, pH-4 to 4.5, Reactant-1M acetic acid solution. Supernatant solution-0.07M Uric acid

Density-1.05 to 1.08, pH-3.8 to 6, Reactant-1 to 1.5M orthophosphoric acid Supernatant solution-1 to 1.5M CaCl2 Density-1.06, pH-6, Reactant-2.5M orthophosphoric acid Supernatant solution-1M CaCl2

Summary. The gel technique is the simplest technique to grow various types of pure as well as mixed crystals, which are sparingly soluble in water. This technique can also be used to grow various types of biological crystals such as urinary stone crystals, cholesterol crystals and crystals responsible for arthritis. This technique is used to identify certain fruit juices and herbal extracts for growth inhibition of Urinary stone problem, arthritis and cholesterol problems. Experts can use the results to develop clinical formulations. Acknowledgement. The author is thankful to the Head of the Physics Department, Saurashtra University, Rajkot and Gujarat, India for the support. The author is very much thankful to the Guide Prof. Mihir Joshi, Physics Department, Saurashtra University, Rajkot, Gujarat, India for his keen interest and valuable suggestions. References [1] H. K. Henisch, Crystal Growth in Gels. Pennsylvania State University Press, University Park, Pennsylvania, 1970. [2] A. R. Patel, A. V. Rao, Review on crystal growth in gel media. Bull. Mater. Sci., 4 1982 527. [3] S. R. Suthar, S. J. Joshi, B. B. Parekh, M. J. Joshi, Dielectric study of Cu+2 doped calcium tartrate tetrahydrate crystals. Indian J. of Pure and Appl. Phys., 45 2007 48-51. [4] R. M. Dabhi, M. J. Joshi, Dielectric studies of gel grown zinc tartrate crystals. Indian J. of Phys., 79(5) 2005 503-507.

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[5] H. O. Jethva, M. V. Parsaniya, Growth and characterization of lead tartrate crystals. Asian J. of Chem., 22(8) 2010 6317-6320. [6] S. J. Joshi, B. B. Parekh, K. D. Vora, M. J. Joshi, Growth and characterization of gel grown pure and mixed iron–manganese levo-tartrate crystals. Bull. Mater. Sci., 29(3) 2006 307-312. [7] H. O. Jethva, P. M. Vyas, K. P. Tank, M. J. Joshi, FTIR and thermal studies of gel-grown, lead– cadmium-mixed levo tartrate crystals. J. Therm. Anal. Calorim., 117(2) 2014 589-594. [8] S J Joshi, K P Tank, P M Vyas, M J Joshi, Structural, FTIR, thermal and dielectric studies of gel grown manganese–copper mixed levo tartrate crystals. J. Cryst. Growth, 401 2014 210-214. [9] S. J. Joshi, K. P. Tank, B. B. Parekh, M. J. Joshi, Characterization of gel grown iron-manganesecobalt ternary levo-tartrate crystals. Cryst. Res. Technol. 45(3) 2010 303-310. [10] C. K. Chauhan, K. C. Joseph, B. B. Parekh, M. J. Joshi, Growth and characterization of Struvite crystals. Indian J. of Pure & Appl. Phys., 46 2008 507-512. [11] P. M. Vyas, S. R. Vasant, R. R. Hajiyani and M. J. Joshi, Synthesis and Characterization of Cholesterol nanoparticles by using w/o microemulsion technique. AIP Conference Proceedings, 1276 2010 198-209. [12] B. B. Parekh, B. V. Jogiya, P. M. Vyas, A. A. Raut, A. B. Vaidya, M. J. Joshi, In vitro growth inhibition study of hydroxyapatite crystals in the presence of selected herbal extract solutions. Der Pharma Chemica, 6(5) 2014 128-135. [13] B. B. Parekh, S. R. Vasant, K. P. Tank, A. Raut, A. D. B. Vaidya, M. J. Joshi, In vitro Growth and Inhibition Studies of Monosodium Urate Monohydrate Crystals by Different Herbal Extracts. American Journal of Infectious Diseases, 5(3) 2009 225-230. [14] K. C. Joseph, B. B. Parekh, M. J. Joshi, Inhibition of growth of urinary type calcium hydrogen phosphate dehydrate crystals by tartaric acid and tamarind. Current Science, 88(8) 2005 1232-1238. [15] V. S. Joshi, B. B. Parekh, M. J. Joshi, A. B. Vaidya, The herbal extracts of Tribulus terrestris and Bergenia Ligulata inhibit growth of calcium oxalate monohydrate crystals in vitro. J. Crystal Growth, 275 2005 e1403. Cite the paper H.O. Jethva, (2017). Gel Growth: A Brief Review. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.64.79.613

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Importance of Impedance Spectroscopy Technique in Materials Characterization: A Brief Review45 M.J. Joshi1 1 – Crystal Growth Laboratory, Physics Department, Saurashtra University, Rajkot, India DOI 10.2412/mmse.42.57.345 provided by Seo4U.link

Keywords: Nyquist plot, Grain and Grain Boundary Effect, gel growth, slow evaporation method, nanoparticles.

ABSTRACT. Impedance spectroscopy is a popular analytical tool in materials research and gives plenty of information after careful analysis. Experimentally obtained data can be analyzed by using a mathematical model based on possible physical theory that predicts theoretical impedance or a relatively empirical equivalent circuit. In the present review the complex impedance plots, i.e. Nyquist plots are analyzed by Z-view software and the values of grain and grain boundary resistances and capacitances are evaluated and the equivalent circuits are proposed for different materials. The results of pure and doped lead tartrate crystals, pure and amino acid doped ADP crystals and pure Hydroxyapatite nano-particles are reviewed. It has found that grain and grain boundary effects are very sensitive to doping and it is reflected in Nyquist plots. From the results it is found that the impedance spectroscopy technique is a sensitive technique to detect impure or doped system.

Introduction. Impedance spectroscopy is an analytical tool in materials science and can be used to study mass transport, rates of chemical reaction, corrosion, dielectric properties, defects, microstructures and conductance in solids. Impedance spectroscopy also finds application in assessing the performance of chemical sensors and fuel cells, electrochemical processes and study of membrane behavior of living cells [1-3]. Several workers have reported the impedance study on different materials, for example, potassium selective silicone rubber membranes [4], effect of Cr concentration on the electrical properties of SnO2 based ceramics [5], CdS nanoparticles [6], lead free (Na 0.5Bi0.5)TiO3 (NBT) ferroelectric ceramics [7], manganese mercury thiocyanate (MMTC) [8], polycrystalline Pr 0.8Ca0.2MnO3 [9], Coimplanted ZnO single crystals [10] and granular type barrier magnetic tunnel junctions based on Co/Cox(Al2O3)1-x/ Co tri-layer structures very recently [11]. In bio-medical applications, the monitoring of the tissue responses to inserted neural implants [12] and for body fluid volume measurements [13] the impedance spectroscopy used. In the present brief review the attempt is made to give the over view of the results obtained in the author’s laboratory in last couple of years on different systems, viz., pure and doped lead tartrate dendrite crystals grown by the gel method, pure and amino acid L-serine doped ammonium dihydrogen phosphate (ADP) crystals and Hydroxyapatite (HAP) nano-particles. In terms of applying complex impedance study, particularly, the Nyquist plots, in order to evaluate the grain and grain boundary contributions. It is worth noting that these three different types of crystalline and nanocrystalline samples are very important from the application point of view [14-16] and considered in this review.

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Experimental Technique. Three different systems of samples have been used for the complex impedance study. (1)For the growth of pure and doped lead levo tartrate crystals, the single diffusion gel growth technique was used with glass test tubes as a crystallization apparatus. To grow pure and mixed lead levo tartrate crystals, 1M levo tartaric acid solution was mixed with sodium meta-silicate solution of specific gravity 1.05 in such a manner that 4.5 pH of the mixture could be obtained. The mixture was transferred into different test tubes to set in to the gel form. After setting the gel the supernatant solutions consisting of lead nitrate (Pb(NO3)2) for the growth of pure lead levo tartrate was poured, while the solution of appropriate metal nitrate was poured in different volume along with lead nitrate solution for the growth of doped crystals. After 20 days the crystals were grown in the gel medium. Three different ions, viz., iron, cobalt and cadmium, were selected to dope in lead levo tartrate crystals, and the details are discussed elsewhere in detail [17-19]. The EDAX analysis was performed to estimate the exact concentration of dopant in crystals. Figure 1 shows the growth of lead levo tartrate dendrite crystals in the test tube.

Fig. 1. Crystal of Lead levo tartrate.

Fig. 2. Crystal of 0.8wt% L-Serine doped ADP.

(2) For the growth of nonlinear optical (NLO) material ADP crystals and doping with different amount of amino acid L-Serine, the slow solvent evaporation method was used. For the growth of Lserine doped ADP crystals the different amount of L-serine, i.e., 0.4 wt %, 0.6 wt % and 0.8 wt %, was added in ADP solution. The confirmation of successful doping was obtained from FTIR spectroscopy studies. The details are given by Joshi et al [20]. Figure 2 shows the type of crystal grown. (3) HAP nano-particles were synthesized by the surfactant mediated approach, using calcium nitrate hexahydrate and potassium dihydrogen phosphate, Triton X-100 (a surfactant), while ammonia solution was used to set the pH 9. The molarities of the reacting chemicals were chosen to obtain the Ca/P ratio as 1.67. The resultant precipitates were filtered, washed and dried in a natural atmosphere [21]. The samples were characterized by employing TEM and powder XRD analysis to confirm the nano-size of the particles. The impedance spectroscopy study was carried out on pelletized samples using HIOKI 3532 LCR HITERSTER Meter set up in the range from 100Hz to 10MHz. The complex impedance data were fitted with software Z- view. Complex Plane Analysis The complex plane analysis is a mathematical technique involving real and imaginary parts of the complex electrical quantities like complex impedance, complex admittance, complex permittivity and complex modulus. The expression for impedance Z(Ď&#x2030;) is composed of a real and an imaginary part. If the real part is plotted on the X-axis and the imaginary part on the Y-axis of a chart, a "Nyquist plot" is obtained, which is shown Figure 3a schematically.

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Fig. 3. (a) Typical Nyquist plot (Inset parallel R-C circuit), (b) Grain and Grain boundary response (Inset parallel R-C circuit). In Fig. 3, a the low frequency data are on the right side of the plot and the higher frequencies are on the left. On the Nyquist plot the impedance can be represented as a vector of length |Z|. The angle between this vector and the X-axis is φ. The typical Nyquist plot of Fig. 3, a results from the inset electrical circuit. The semicircle is a characteristic of a single "time constant". Many times the impedance plots contain several time constants and as a result, only a portion of one or more of their semicircles is seen. Grain and Grain Boundary Effects Generally, the ac response of the system considers only the relation between the applied voltage and the current through the test sample. However, the physical nature of the test sample, e.g., single crystal, polycrystalline, blocking or non-blocking electrodes, etc. and its electrical properties, i.e., ionic, electronic or mixed conductor, ferroelectric, etc., are important for consideration. The plausible equivalent circuits, that is, some networking containing ideal resistive and reactive components can be proposed representing these properties of the system and provide model for the collected data. Figure 3b shows the typical Nyquist plot for grain, grain boundary and electrode response and the equivalent circuit shown in inset is widely used to represent the bulk and grain boundary phenomenon and Warburg impedance for electrode response in polycrystalline material [22]. One useful model has been proposed to describe the electrical response of polycrystalline ionic conductors is the brick layer model [23]. The contribution of grain and grain boundaries in the Nyquist plots was discussed in thin yttria stabilized stabilized zirconia layers [24] and in Ba5 HoTi3V7 O30 ceramic [25]. Result and Discussion The Nyquist plots of pure lead levo tartrate crystal exhibits two semi-circular arcs. The arc at high frequency region near the origin gives a notch that was fitted into semi-circular arc by using software Z-view. Figure 4 shows the typical schematic representation of grain and grain boundary contributions along with the equivalent circuit suggested. The values of grain resistance (R g), grain boundary resistance (Rgb), grain capacitance (Cg), grain boundary capacitance (Cgb) and relaxation frequency for grain ( fg) and grain boundary (fgb) were obtained as 0.145 MΩ, 2.38 MΩ , 103 pF, 66.5 pF, 10.6 kHz and 1 kHz, respectively, for the pure lead levo-tartrate crystals. On doping cobalt, cadmium and iron ions the values of grain resistance increased and the grain capacitance decreased, but no contribution from grain boundary was detected and displayed only one semi-circular arcs in the Nyquist plots indicating the grain contribution only and that was fitted with one R-C parallel circuit as shown in Figure 3a schematically. From the EDAX analysis, it was found that even minimum value of dopant around 0.22 wt % gave the single circular arc in the Nyquist plot [17-19].

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Fig. 4. Nyquist plot (inset parallel R-C circuit). The Nyquist plot of pure ADP crystal indicated two semi-circular arcs with grain and grain boundary contributions. The values of Rg, Rgb, Cg, fg and fgb were found to be 27.8 MΩ, 51.1 MΩ, 65.8 pF, 34.9 pF, 546Hz and 561 Hz, respectively. Again it was found that on doping amino acid L-serine in ADP crystals the grain boundary contribution disappeared and only one semi-circular arc was observed. The grain boundary resistance value increased on doping, whereas the grain capacitance value decreased on doping [20]. Altogether, the same behavior was obtained for pure HAP nano-particles. Two semi-circular arcs were obtained in the Nyquist plots indicating grain and grain boundary contributions. The values of Rg, Rgb, Cg, fg and fgb were found to be 14.12 MΩ, 369 MΩ, 9.93 pF,40.41 pF, 3.447kHz and 278 Hz, respectively [21]. From the results of the study conducted on various samples it was found that the dopant entered the grain and modified it properties by changing the grain resistance and grain capacitance values. The dopant also modified the grain boundary behavior and within the range of the frequency studied the grain boundary behavior was not detectable. This behavior was sensitive to the minimum dopant level of 0.22 wt % obtained from EDAX analysis. Summary. The Nyquist plots were found to be sensitive to pristine and impure or doped samples. The pure or pristine samples exhibited both grain and grain boundary contributions with two semicircular arcs, whereas the doped samples exhibited only one semi-circular arc with grain contribution only within the frequency range studied. This was observed for the smallest amount of doping used around 0.22 wt %. It could be concluded that the complex impedance study, particularly, Nyquist plot representation, is sensitive to the purity of the sample and small amount of impurity or doping is reflected in the nature of the plot. However, further study is needed for standardization and validation of this technique. Acknowledgments. The author is thankful to Prof. Hiren Joshi (HOD, Physics Department) for the keen interest and UGC for SAP and DST for FIST grants. The author is thankful to Prof. D.K. Kanchan (M.S. University of Baroda) for his help and Dr. H.O. Jethva, Ms. Bhoomika Jogiya and Mr. Jaydeep Joshi for their inputs. References MMSE Journal. Open Access www.mmse.xyz

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[1] J.R.MacDonald and W.B. Johnson, “Fundamentals of Impedance Spectroscopy”, Impedance Spectroscopy: Theory, Experiment and Applications, 2nd Edn., Eds. E.Barsoukov, Wiley InterScience,2005. [2] J.R. Macdonald and W.R. Kenan, “Impedance Spectroscopy: Emphasizing Solid Materials and Systems”, Wiley, 1987. [3] B. Pejcic and R. de Marco, Impedance Spectroscopy: Over 35 years of Electrochemical Sensor Optimization, Electrochimica acta, 51(2006)6217 DOI. 10.1016/j.electacta.2006.04.025. [4] P. D. Van der Wal, E. J. R. Sudholter, B. A. Boukamp, H. J. M. Bouwmeester and D. N. Reinhoudt; J. Electroanal. Chem., 317 (1991) 153 DOI 10.1016/0022-0728(91)85010-M. [5] D. R. Leite, W. C. Las, G. Brankovic, M. A. Zaghete, M. Cilense and J. A. Varela; Materials Science Forum, 498-499 (2005) 337. [6] J. S. Kim, B. C. Choi and J. H. Jeong; J. of Korean Phys. Soc., 55(2) (2009) 879. [7] R. Tripathi, A. Kumar and T. P. Sinha; Pramana J. Phys., 72(6) (2009) 969. [8] R. Josephine Usha, J. Arul Martin and V. Joseph; Arch. Appl. Sci. Res., 4(1) (2012) 638. [9] M. Shah, M. Nadeem and M. Atif; J. Appl. Phys., 112 (2012) 103718 1-8. [10] M. Younas, L. L. Zou, M. Nadeem, Naeem-ur-Rehman, S. C. Su, Z. L. Wang, W. Anwand, A. Wagner, J. H. Hao, C. W. Leung, R. Lortz , F. C. C. Ling; Phys. Chem. Chem. Phys., 16 (2014) 16030 DOI. 10.1039/C4CP00951G. [11] A.T. Nguyen, T.A. Nguyen, T.N. Nguyen,A.T. Nguyen,V.C. Giap, J. Electronic. Mater. 45(2016)3200 DOI. 10.1007/S11664-016-4453-1. [12] J.C. Williams, J.A. Hippensteel, J. Dilgen, W. Shain and D.R. Kipke, J. Neural. Eng. 4 (2007) 410 DOI. 10.1088/1741-2566/4/4/007 [13] M.Y. Jaffrin and H. Morel, Med. Eng. Phys. 30(2008)1257 DOI.10.1016/j.medengphy. 2008.06.009 [14] U.Tarpara, P.Vyas, 10.1142/S0219581X1550013.

M.J.Joshi,

Int.J.Nanosci.,

14(3)(2015)1-6

DOI

[15] D.N.Nikogosyan, “Nonlinear Optical crystals: A complete survey”, Spinger-Verlag New York, 2005. Doi: 10.1007/b138685. [16] I. Sopyan, M. Mel, S. Ramesh, K.A. Khalid, Sci. and Technol. of Adv. Mater 8 (2007) 116–123 DOI 10.1016/j.stam.2006.11.017 [17] H.O. Jethva, D. Kanchan, M.J. Joshi, Int.J.Innov.Res.Sci.Eng.Tech. 5(1)(2016)221-233 doi:10.15680/IJIRSET.2015.0501029. [18] H.O.Jethva, M.J.Joshi, D.K. Kanchan, Int.J.Eng.and Innov.Tech., 5(3)(2015)99-106. [19] H.O.Jethva, Growth and Characterization of Lead-Cadmium and other mixed levo-tartrate Crystals, Ph.D. Thesis, Saurashtra University, Rajkot, 2015. [20] J.H. Joshi, K.P. Dixit, M.J. Joshi, K.D. Parikh, AIP Conf.Proc., 1728(2016)1-4 DOI.10.1063/1.4946270. [21] B. V. Jogiya , H. O. Jethava, K. P. Tank, V. R. Raviya and M. J. Joshi, AIP conference proceeding, 1728 (2016)1-4 DOI: 10.1063/1.4946278. [22] D. C. Sinclair; Bol. Soc. Esp. Ceram. Vidrio., 34 (1995) 55. [23] J. Habasaki, C. Leon, K.L. Ngai, “Dynamics of Glassy, Crystalline and Liquid Ionic Conductors: Experiments, Theories and Simulations”, Springer, 2016. MMSE Journal. Open Access www.mmse.xyz

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[24] M. Gerstl, E. Navickas, G. Friedbacher, F. Kabel, M. Ahrens and J. Fleig, Solid State Ionic, 185(2011)32 DOI 10.1016/j.sso.2011.01.008 [25] K.Kathayat, A. Panigrahi, A. Pandey and S. Kar, Mater. Sci. A Appl,3 ( 2012)390 DOI 10.4326/msa.2012.36056. Cite the paper M.J. Joshi (2017). Importance of Impedance Spectroscopy Technique in Materials Characterization: A Brief Review. Mechanics, Materials Science & Engineering, Vol 9. doi 10.2412/mmse.42.57.345

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A Combined Experimental and Theoretical Investigations on N, N′Diphenylguanidine Based Single Crystals For Nonlinear Optical Applications 46 G. Saravana Kumar1, R. Roop Kumar2, P. Murugakoothan1, a 1 – MRDL, PG and Research Department of Physics, Pachaiyappa’s College, Chennai-600030, India 2 – Birla Institute of Technology and Science, Pilani, Dubai Campus, Dubai, United Arab Emirates a – murugakoothan03@yahoo.co.in DOI 10.2412/mmse.96.99.996 provided by Seo4U.link

Keywords: crystal growth, single crystal XRD, density functional theory (DFT), nonlinear optical materials (NLO). ABSTRACT. Good quality N,N′-Diphenylguanidine based nonlinear optical single crystals were grown by slow evaporation technique. The cell parameters and space group were confirmed by single crystal X-ray diffraction analysis. The UV-vis study was carried out to assess the transmittance of the title crystals. The optical band gap was determined from the UV-vis analysis. The HOMO-LUMO analysis was carried out using DFT calculations. The presence of second harmonic generation (SHG) was confirmed by Kurtz-Perry powder technique. The existence of microscopic nonlinear optical property was investigated using DFT analysis. The laser and mechanical stability was studied by laser damage threshold (LDT) and Vicker’s microhardness analysis.

Introduction. Nonlinear optical (NLO) materials have attracted and are gaining enormous demand due to their wide applications in the recent technologies, like optoelectronics, lasers, data storage systems and optical communications. In addition to their large NLO response, the advantage of organic materials is that they offer high degree of synthetic flexibility to tailor their optical properties through structural modification [1]. Guanidinium derivatives are of great biological importance due to its presence as the functional group of amino acid arginine, the muscular energy-intermediate creatine, the pyrimidine bases of DNA, and a number of other biologically active molecules [2]. Guanidine and its derivatives are now gaining importance in the field of nonlinear optics [3]. Computational methods are important tools to provide prior information on the structure dependent nonlinear optical response of the molecules and several properties of interest. In this present investigation, we are reporting the crystal growth, structural analysis, linear and nonlinear optical properties, laser damage threshold (LDT) and mechanical properties of N,N′-Diphenylguanidine based series of crystals namely N,N'-diphenylguanidinium nitrate (DPGN), N,N'diphenylguanidinium hydrogen(+)-L-tartrate monohydrate (DPGTM) and N,N'diphenylguanidinium dihydrogen phosphite (DPGP) along with the Density Functional Theory (DFT) analysis for linear and nonlinear optical properties. Experimental Procedure. The single crystals of DPGN, DPGTM and DPGP were synthesized using analytical grade N,N′- diphenylguanidine and the corresponding acids namely, nitric acid, L-tartaric acid and phosphorus acid in stiochiometric ratio (1:1) by slow evaporation technique. The synthesized salt was purified by successive recrystallization. For the synthesis and growth of DPGN single crystal, the calculated amount of N,N′- diphenylguanidine and nitric acid were dissolved using methanol. However for the case of DPGTM and DPGP a mixed solvent of ethanol+water in an equimolar ratio of 1:1 was used. The respective solutions were allowed to stirr well in order to obtain homogeneity. The solutions were filtered, transferred to a beaker and was covered with aluminium foil and kept © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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undisturbed. Good quality single crystals of DPGN, DPGTM and DPGP were harvested after a period of 40, 96 and 36 days respecctively and the photographs are shown in Fig. 1.

Fig. 1. As grown single crystal of (a) DPGN, (b) DPGTM and (c) DPGP. Characterization technique. The single crystal X-ray diffraction analysis of the grown N,N'Diphenylguanidine series of crystals was carried out using ENRAF NONIUS CAD4 automatic X-ray diffractometer with MoKα(λ = 0.7170 Å) radiation. UV-vis transmission spectrum was recorded using VARIAN CARY 5E UV-vis spectrophotometer. The second harmonic generation nonlinearity of N,N'-diphenylguanidine based crystals in the present work was studied by Kurtz-Perry powder test. An actively Q-switched Nd:YAG laser in TEM00 mode with pulse width 10 ns and repetition rate 10 Hz was used for the laser induced damage threshold study. Selected smooth and flat surface of the grown crystals was subjected to micro hardness study at room temperature using Vicker’s hardness tester (LEITZ WETZLER). The theoeritical calculations for microscopic linear and nonlinear optical properties were carried out using DFT by employing GAUSSIAN 03 W computational software. Results and discussion. Structural analysis.The single crystal X-ray diffraction study reveals that the DPGN and DPGTM crystals belong to orthorhombic crystal system with Pna21and P212121 as space group, and the DPGP crystal belongs to tetragonal crystal system with P43 as space group. The unit cell parameters and space group of DPGN, DPGTM and DPGP agrees well with the reported data [4, 5, 6]. Geometry optimization of DPGN, DPGTM and DPGP was carried out from the X-ray experimental atomic position Crystallographic Information File (CIF) of the corresponding structure and then all other calculations engaging density functional theory (DFT) were performed by the resultant optimized structural parameters. The optimized structures of DPGN, DPGTM and DPGP are shown in Fig. 2.

Fig. 2. Optimized geometrical structure of (a) DPGN, (b) DPGTM and (c) DPGP. Linear optical properties.The transmission range of the as grown N,N'-diphenylguanidine crystals, was determined by recording the optical transmission spectrum in the wavelength range 200 - 800 nm. The polished crystals of thickness 2 mm were used for this measurement. The transmittance MMSE Journal. Open Access www.mmse.xyz

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spectra of DPGN, DPGTM and DPGP are shown in Fig.3. The cut-off wavelengths of DPGN, DPGTM and DPGP were found to be 310 nm, 298 nm and 294 nm respectively. The percentage of transmission of about 56%, 76% and 70% for DPGN, DPGTM and DPGP is attributed to better quality of the grown crystals. The Taucâ&#x20AC;&#x2122;s graph plotted between the square of the product of absorption coefficient and the incident photon energy (đ?&#x203A;źâ&#x201E;&#x17D;đ?&#x153;&#x2C6;)2 with the photon energy (â&#x201E;&#x17D;đ?&#x153;&#x2C6;) at room temperature shows a linear behavior and was used to determine optical band gap value for the title crystals by extrapolation of the linear portion near the onset of absorption edge to the energy axis and are shown in Fig. 4.

Fig. 3. UV-vis transmission spectra.

Fig. 4. Taucâ&#x20AC;&#x2122;s plot between (đ?&#x203A;źâ&#x201E;&#x17D;đ?&#x153;&#x2C6;)2 and (â&#x201E;&#x17D;đ?&#x153;&#x2C6;).

HOMO â&#x20AC;&#x201C; LUMO analysis.The molecular structure of DPGN and DPGP was optimized using B3LYP, hybrid function consisting of Beckeâ&#x20AC;&#x2122;s three-parameter non-local exchange function with the correlation function of Lee, Yang and Parr employing B3LYP/6-31G (d, p) basis set. However for DPGTM the same level of theory was employed with B3LYP/6-31G (d) as basis set. The HOMO â&#x20AC;&#x201C; LUMO analysis was carried out for DPGN, DPGTM and DPGP from their corresponding optimized molecular structure. The HOMOâ&#x20AC;&#x201C;LUMO energy gaps are 4.87 eV, 5.04 eV and 5.34 eV for DPGN, DPGTM and DPGP respectively. The HOMO â&#x20AC;&#x201C; LUMO plots of DPGN, DPGTM and DPGP are shown in Fig. 5. (a), (b) and (c) respectively.

Fig. 5. HOMO â&#x20AC;&#x201C; LUMO plots of (a) DPGN, (b) DPGTM and (c) DPGP. MMSE Journal. Open Access www.mmse.xyz

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Nonlinear optical study The second harmonic generation nonlinearity of the as-grown N,N'-diphenylguanidine based crystals in the present work was studied by Kurtz â&#x20AC;&#x201C; Perry powder test [7]. A fundamental beam from Qswitched Nd: YAG laser (Îť = 1064 nm) was passed through the powder sample of grown crystals. The SHG behavior is confirmed from the output of the laser beam which had bright green emission (Îť = 532 nm) from the powder sample. The second harmonic signals of 14.2 mV, 14 mV and 15.2 mV were obtained for DPGN, DPGTM and DPGP powder crystalline samples respectively, for an input energy of 5 mJ/pulse, while the standard potassium dihydrogen phosphate (KDP) powder crystal sample gave a SHG signal of 15.4 mV for the same input energy. It shows that the SHG effective nonlinearities of DPGN, DPGTM and DPGP are 0.92, 0.90 and 0.98 times respectively that of standard NLO material KDP. Nonlinear optical calculations In a medium, the nonlinear optical effects arise when the medium interact with the electromagnetic field of intense laser beam. Since the Gaussian 03 output values of the polarizability and the hyperpolarizability tensors components are reported in atomic units (a.u.), the calculated values have been converted into electrostatic units (esu) [Îą : 1 a.u. = 0.1482 Ă&#x2014; 10â&#x2C6;&#x2019;24 esu ; Î˛ : 1 a.u. = 8.3693 Ă&#x2014; 10â&#x2C6;&#x2019;33 esu).The computed values of dipole moment (đ?&#x153;&#x2021;đ?&#x2018;&#x2013; ), polarizability (Îą), first order hyperpolarizability (đ?&#x203A;˝đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;Ą ) of DPGN, DPGTM and DPGP compounds with B3LYP/6-31 G (d,p), B3LYP/6-31 G (d), B3LYP/6-31 G (d,p) basis set are presented in Table. 1. Table 1. Computed Nonlinear optical parameters. _______________________________________________________________________________ Parameters

DPGN

DPGTM

DPGP

_______________________________________________________________________________________________ Dipole moment (đ?&#x153;&#x2021;đ?&#x2018;&#x2013; (đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;Ą) )

10.421 D

4.3552 D

9.9678 D

Polarizability (Îątot)

21.95 Ă&#x2014; 10â&#x2C6;&#x2019;24 esu

26.17 Ă&#x2014; 10â&#x2C6;&#x2019;24 esu

21.01 Ă&#x2014; 10â&#x2C6;&#x2019;24 esu

84.052Ă&#x2014; 10â&#x2C6;&#x2019;31 esu

30.2353 Ă&#x2014; 10â&#x2C6;&#x2019;31 esu

27.057Ă&#x2014; 10â&#x2C6;&#x2019;31 esu

First order hyperpolarizability, (đ?&#x203A;˝đ?&#x2018;Ąđ?&#x2018;&#x153;đ?&#x2018;Ą )

________________________________________________________________________________________________

This high value of (Î˛) and the non-zero value of (đ?&#x153;&#x2021;đ?&#x2018;&#x2013; ) are responsible for the enhancement of second harmonic generation properties of the title compounds at molecular level. Laser induced damage threshold study.The laser parameters, such as energy, wavelength, pulse duration, longitudinal and traverse mode structure, beam size and location of beam are the factors on which the laser damage threshold depends upon [8]. A well-polished sample of the grown crystals with clean surface and prominent face was subjected to the multiple shot (10 shots per second) LDT study. Energy density or energy fluence is a measure used to describe the energy delivered per unit area. The energy density of the input laser beam for which the crystal gets damaged was recorded using a power meter.The radius of laser beam was 1 mm. The energy density was calculated using the formula, Energy density = E /A, where, E the input energy (mJ) and A the area of the circular spot (mm) expressed in J/cm2. The energy fluence of DPGN, DPGTM and DPGP were found to be 20.7, 13.1 and 6 J/cm2 respectively.

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Microhardness analysis. The hardness measurement for DPGN, DPGTM and DPGP crystals was carried out on their prominent planes respectively. The micro hardness value was calculated using the relation, đ??ťV = 1.8544 (đ?&#x2018;?â &#x201E;đ?&#x2018;&#x2018;2 ) kg/mm2. The micro hardness measurements were made for the applied loads varying from 5 to 35 g by keeping the constant dwell time of 3 s for all cases. A plot between the hardness number and load for the grown crystals are shown in Fig. 6.

Fig. 6. Plot of hardness number vs. load. We clearly infer from the Fig.6., that the micro hardness number increases with increasing the load. This trend is in agreement with the reverse indentation size effect (RISE). The load above these values develops multiple cracks on the crystal surface due to the release of internal stresses generated locally by indentation. Summary. Optically good quality single crystals of DPGN, DPGTM and DPGP were grown by slow evaporation technique. The single X-ray diffraction (SXRD) study confirms that the title crystals are crystallized in non-centrosymmetric space group. The DFT was employed to optimize the structural geometry of the title compounds and was found to be true without any negative frequencies. The percentage of transmission, the transparency range and the band gap energy of the grown crystals were determined from UV-vis transmittance analysis. The title crystals are high band gap energy compounds with good transmission in the entire visible region. The HOMO â&#x20AC;&#x201C; LUMO band gap were computed. All the grown crystals are found to be NLO active and SHG nonlinearity is almost equivalent to that of KDP. The nonlinear optical parameters, such as dipole moment, polarizability and first order hyperpolarizability were computed in order to understand NLO behaviour at molecular level. The laser damage threshold and Vickerâ&#x20AC;&#x2122;s micro hardness study confirm that the grown crystals exhibit higher stability to laser and mechanically stress. References [1] P. Vivek, P. Murugakoothan, Growth and anisotropic studies on potential nonlinear optical crystal imidazole-imidazolium picrate monohydrate (IIP) in different orientations for NLO device fabrications, Opt. & Laser. tech., Vol. 49, pp. 288â&#x20AC;&#x201C;295, 2013, DOI:10.1016/j.optlastec.2013.01.015. [2] C. James, V.S. Jayakumar, I. Hubert Joe, Natural bond orbital analysis and vibrational spectroscopic studies of H-bonded N,N'-diphenylguanidinium nitrate, J. Mol. Str., Vol. 830, pp. 156166, 2007, DOI:10.1016/j.molstruc.2006.07.014. [3] G. Saravana Kumar, P. Murugakoothan, Synthesis, spectral analysis, optical and thermal properties of new organic NLO crystal: N,Nâ&#x20AC;˛-Diphenylguanidinium Nitrate (DPGN), Spectrochim. Acta Part A., Vol. 131, pp. 17â&#x20AC;&#x201C;21, 2014, DOI: 10.1016/j.saa.2014.04.059.

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[4] J.A. Paixao, P.S. Pereira Silva, A. Matos Beja, M. Ramos Silva, L. Alte da Veiga, Crystal structure of N,N' – Diphenylguanidinium Nitrate, Acta Cryst. C., Vol. 54, pp. 805-808, 1998, DOI: 10.1107/S0108270198003084. [5] J.A. Paixao, P.S. Pereira Silva, A. Matos Beja, M. Ramos Silva, E. De Matos Gomes, M. Belsley, Crystal structure of N,N' – Diphenylguanidinium hydrogen (+) – L – Tartrate monohydrate, Acta Cryst. C., Vol. 55, pp. 1287-1290, 1999, DOI:10.1107/S0108270199005119. [6] J.A. Paixao, A. Matos Beja, M. Ramos Silva, L. Alte da Veiga, Crystal structure of N,N' – Diphenylguanidinium dihydrogen phosphite, Z. Kristallogr. NCS., Vol. 216, pp. 416 – 418, 2001, DOI: 10.1524/ncrs.2001.216.14.438. [7] G. Saravana Kumar, P. Murugakoothan, Synthesis, spectral, optical and electric studies of N,N'diphenylguanidinium hydrogen (+)-L-tartrate monohydrate – A new organic NLO crystal, Optik, Vol. 126, pp. 68–73, 2015, DOI:10.1016/j.ijleo.2014.07.137. [8] G. Saravana Kumar, G. Mano Balaji, P. Murugakoothan, Experimental and theoretical investigations on N,N'-diphenylguanidinium dihydrogen phosphite – A semi – organic nonlinear optical material, Spectrochim. Acta Part A., Vol. 138, pp. 340–347, 2015, DOI: 10.1016/j.saa.2014.11.054. Cite the paper G. Saravana Kumar, R. Roop Kumar, P. Murugakoothan, (2017). A Combined Experimental and Theoretical Investigations on N,N′-Diphenylguanidine Based Single Crystals For Nonlinear Optical Applications. Mechanics, Materials Science & Engineering, Vol 9. 10.2412/mmse.96.99.996

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Facile Preparation and Characterization of Polyaniline-iron Oxide Ternary Polymer Nanocomposites by Using “Mechanical Mixing” Approach47 N. Dhachanamoorthi1, a, L. Chandra2, P. Suresh3, K. Perumal4 1 – Assistant Professor, PG Department of Physics, Vellalar College for Women, Erode-12, Tamilnadu, India 2 – Assistant Professor, Department of Physics, Chikkaiah Naicker College, Erode-4, Tamilnadu, India 3 – Assistant Professor, Department of Physics, Erode Arts & Science College, Erode-9, Tamilnadu, India 4 – Associate Professor (Retired), Department of Physics, Sri Ramakrishna Mission Vidyalaya college of Arts and Science, Coimbatore-20, Tamilnadu, India a – dhachu83@gmail.com DOI 10.2412/mmse.41.37.672 provided by Seo4U.link

Keywords: polyaniline, Fe3O4, nanocomposites, nanoparticles, antibacterial activity.

ABSTRACT. Polymer science and technology has received momentous research consideration in last some decades. An effortless and cost-effective access to the synthesis of a nanocomposite material of polyaniline (PANI)-iron oxide Fe3O4 nPs has been improved. Polyaniline-iron oxide (PANI-nFe3O4) nanocomposites were synthesized by increasing the wt% of nano iron oxide (nFe3O4) with in the presence of PANI materials. Mechanical mixing method is used in the preparation of PANI-nFe3O4 nanocomposites material. The chemical structure of pure PANI and PANI-nFe3O4 nanocomposites is characterized by using Fourier Transform infrared spectroscopy and it is also used to analyze the stretching vibration, wavenumber shifting and chemical structure changes of nanocomposites. The optical properties were characterized by using UV-Visible spectroscopy and the band gap value of pure PANI, PANI-nFe3O4 (50%), PANI-nFe3O4 (100%) are 3.284 eV, 3.214 eV and 3.201 eV respectively; it was observed that the band gap value of nanocomposites decreased with increase in the concentration of Fe3O4 nanoparticles. Crystalline nature of pure PANI and its nanocomposites were analysized by using the X-Ray diffraction spectroscopy. pure PANI has amorphous nature. By increasing the iron oxide nPs the amorphous nature of pure PANI decreases while its crystalline nature increases. The bacterial growth (E-Coli and staphylococcus aureus), the resultant increase in the zone of inhibition due to increase in the weight % of Fe 3O4 nPs were studied using antibacterial activity.

Introduction. In recent research, the preparation of conducting polymer nanocomposites (CPnCs) has obtained a great deal of interest in physics and chemistry materials research community because of different potential applications of these materials in chemical sensing, polymer batteries catalysis, energy storage, solar cells, light emitting diode (LED), organic light emitting diode (OLED) and medical diagnosis etc., [1]. The synthesis of organic-inorganic nanocomposites has become the subject of extensive studies. The nanocomposites containing organic polymers (polyaniline, polypyrrole, polythiophene, poly-o-toluidine etc.,) and inorganic particles in nano metal oxide (nFe3O4, nNiO, nSb2O3, nZnO, nTiO2, nCuO, nCrO2, nV2O5 and nAl2O3 etc.,) provide an entirely new class of materials with novel properties. Nowadays, syntheses of new CPnCs with improved mechanical properties, processability, or heat resistance in comparison to corresponding pure conducting polymers alone, as well as the studies of their electrical, optical, magnetic, and catalytic properties constitute a great scientific challenge [2]. Polyaniline (PANI) is one of the most extensively studied conducting polymers because of its simple synthesis and doping-dedoping chemistry, low cost, high conductivity, excellent environmental stability, and wide potential applicability, erasable optical information storage, shielding of electromagnetic interference, microwave and radar © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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absorbing materials, indicators, catalysts, electronic and bioelectronic components, membranes, electrochemical capacitors, electrochromic devices, nonlinear optical, electromechanical actuators, antistatic and anticorrosion coatings, high specific capacitance and electroactivity etc., The nanosized metallic particles have attracted attention of the materials community due to their unique properties [3]. In the present work, PANI-nFe3O4 nanocomposites were prepared by increased Fe nanoparticles in the presence PANI and different contents of Fe nanoparticles. PANI is a conducting polymer that contains positively charged amine/imine groups on its polymer chain, which may favor adhesion onto the Fe surface. Experimental. All of the chemical reagents used in this experiment were A.R. grade. The monomer aniline (ANI) and sulphuric acid (H2SO4) as dopant were used as received. The polyaniline was synthesized by chemical oxidative polymerization under static condition in a lower temperature (0- 5 ˚C). Sulphuric acid (H2SO4) as a dopant was dissolved in about 500 mL of deionized water and the solution was well stirred in round-bottomed flask. Monomer aniline was added in the above suspension solution and keeps stirring for 0.5 hrs. After 0.5 h ammonium peroxydisulfate (NH4)2S2O8 as an oxidant was added drop wise slowly, until good degree of polymerization is achieved which results in green coloured solution. The entire mixture was continuously stirred well at 0-5 ˚C and the reaction was continued for another 24 h overall time speed of rotation was maintained at 600 rpm. The product was filtered and washed with deionized water, ethanol and acetone and by using ammonia solution the emeraldine salt form of polyaniline is change the emeraldine base form, then dried under vacuum at 70 ˚C for 24 h. PANI-nFe3O4 nanocomposites were prepared using different (50 and 100 %) wt % of nFe3O4 with respect to polyaniline which are referred as PANI-nFe3O4 nanocomposites. The molar ratio of polymer (PANI) and metal oxide (nFe3O4) was for the preparation of PANI-nFe3O4 (50 %) nanocomposites by using mechanical mixing method and similarly the samples were prepared in the different wt % of nFe3O4 nanoparticles PPy-nFe3O4 (100 %) by the ratio 1:0.50 and 1:1, respectively. Result and discussion. FTIR Spectra. The surface functional groups have been verified and the structural information on all the nanocomposites materials and transmittance of polyaniline in the PANI-nFe3O4 nanocomposites was identified by FTIR spectral investigation. The FTIR spectrum of pure PANI and PANI-nFe3O4 (50%, 100%) nanocomposites are clearly showed in Fig.1. In the FTIR spectra of pure PANI (Fig.1a) eight sharp, broad absorptions peaks are obtained. The first peak the band at 3417 cm1 attributed to N-H stretching vibration and the transmittance for this peak is 53.66 [4]. The second peak is observed at 1586 cm-1 assigned to C=C stretching mode of vibration for the quinoid unit and transmittance peak value is 34.05 [5]. The bands 1499 cm-1 is attributed to C=C stretching vibration for the benzoid unit this peaks is third peak of the spectrum of pure PANI and the transmittance value (54.38). This above two peaks of the pure PANI spectrum the second peak (C=C quinoid) is very strong peak and the third peak (C=C) benzoid) very weak peak. The band at 1399 cm-1 is attributed in C-N stretching vibration (Q=N−B) and transmittance is (41.48) [7]. The fifth absorption band of pure PANI spectrum is assigned at 1316 cm -1 and this band observed in C−N stretching of the secondary aromatic amine and which transmittance band value are 61.90 [6]. The six peaks at 1123 cm-1 are assigned to in-plane bending modes of C-H stretching and the seventh peak obtained at 817 cm-1 to out-plane bending modes of C-H stretching vibration. The absorptions at lower wavenumber (622 cm-1) belong to the nFe-O and nFe-O-nFe vibration modes of nFe3O4 nPs [7]. FTIR Spectrum of PANI-nFe3O4 (50%, 100%) nanocomposites both is similar to pure PANI. This two nanocomposites spectrum also have eight bands are obtained. In PANI-nFe3O4 (50%) nanocomposites the stretching vibrations at 3414, 1587, 1497, 1396, 1307, 1131, 830 and 620 cm-1 this region were assigned at N-H stretching vibration, C-H stretching vibration (quinoid), C-H stretching vibration (benzoid), C-N stretching vibration, C−N (Secondary aromatic amine), C-H inplane bending mode, C-H out plane bending mode, Fe-O-Fe stretching vibration respectively, (Fig.1b) prove the presence of emeraldine base state of PANI in our synthesized nanocomposites [9]. MMSE Journal. Open Access www.mmse.xyz

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This interesting phenomenon specifies there is a good interaction between PANI and nFe 3O4 and also confirmed the doping of Fe in the PANI. For PANI-nFe3O4 nanocomposites, the shifting of peaks at lower wavenumber is mainly due to the π-π conjugated interaction between the benzene ring of PANI and the metal oxide, indicating a strong interaction between PANI and the nFe 3O4 nPs [10].

Fig. 1. FTIR spectra of pure PANI (a) and PANI-nFe3O4 (50, 100%) nCs (b) and (c). UV-Vis Spectra. UV-Vis spectra of pure PANI and PANI-Fe3O4 nanocomposites are shown in Fig.2, the optical properties of the PANI and the nanocomposites of UV-visible absorption spectroscopy analyses were performed. The spectrum of pure PANI show that there are two absorption bands of PANI at 328 and 627 nm, which are assigned to π-π* transition of the benzenoid ring and n-π* excitation of benzenoid to the quinoid ring in the polymer chain. The band gap was calculated by means of the Tauc equation αhν = B(hν-Eg )n where α is the absorption coefficient, h is the Planck constant, ν represents the photon frequency, B is a fitting parameter, Eg is the band gap, and n is the different possible electronic transitions responsible for the light absorption. For PANI and its nanocomposites, n= 12 The band gap was obtained by plotting the UV-Vis spectra as (αhν)2 vs hν and extrapolating the linear portion of (αhν)2 vs hν to zero, shown in Fig. 3 (a-c) The calculated Eg values were 3.284 eV for the pure PANI. Furthermore, compared with pure PANI, the absorption bands of the two nanocomposites both show a little blue shift about ±4 nm. The blue shift of the band gap for the PANI-Fe3O4 (50, 100%) nanocomposites clearly indicates that the metal ions strongly bind with the PANI matrix chain.

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Fig. 2. UV-Vis Spectrum of Pure PANI (a) and PANI-Fe3O4 (50%, 100%) nCs (b), (c).

Fig. 3. Tauc Plot of Pure PANI (a) and PANI-nFe3O4 (50,100%) nCs (b), (c). The Eg value of PANI-Fe3O4 (50%), PANI-Fe3O4 (100%) is 3.214 eV and 3.201 eV respectively; compared to the pure PANI the band gap value is decreased with increasing the wt % of dopant concentration in the nanocomposites samples and Tauc plot of pure PANI and nanocomposites is shown in Fig.3.In both the cases, the band gap is decreased by the incorporation of doping agents inside the materials. The comparison of pure PANI and nanocomposites the peak intensity of the nanocomposites is decreased with increasing the Fe ion concentration. This blue shifting and peak intensity phenomenon of the absorption peak in PANI-nFe3O4 nanocomposites may be due to the doping effect. It is also observed that there is a blue shifting of the peak for the PANI-nFe3O4 nanocomposites, only because of some interaction between the quinonoid ring of PANI and nFe 3O4 nPs.

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XRD Studies. Fig.4 (a-c) shows XRD patterns of the pure PANI and PANI-nFe3O4 nanocomposite. In case of pure PANI, a broad amorphous peak observed at 20.52˚ 2θ was assigned to the periodicity parallel to the polymer chain [8]. XRD of PANI-nFe3O4 indicated that the nanocomposite is crystalline and showed a XRD peaks. The crystallite sizes were estimated using the full width at half maxima of the XRD peaks. Using the Scherrer formula, the expression for the full width at half maximum of the XRD peaks can be expressed as t = Kλ/β cos θ where K is the grain shape factor (0.89 for spherical), λ is the wavelength of CuKα (1.5406 Å), t is the thickness of the crystal and θ is the Bragg’s angle.

Fig. 4. XRD Pattern of Pure PANI (a) and PANI-Fe3O4 (50%, 100%) nCs (b), (c). XRD patterns of PANI-nFe3O4 (50%) nanocomposites (Fig.4b) reveal the presence of crystalline nature with nFe3O4 nPs. A sharp peak appeared at the range of 2θ≈30.20-86.70 and for these range 11 sharp peaks for crystalline nature of nFe3O4 nPs. The crystalline peaks centered at 2θ≈30.20, 35.64, 43.29, 53.60, 57.29, 62.95, 65.31, 69.96, 74.34, 78.59, and 86.70˚ correspond to the (220), (311), (400), (422), (511), (440), (531), (620), (622), (444) and (642) crystal planes of the cubic structure of nFe3O4 nPs [9]. In the PANI-nFe3O4 (100%) nanocomposites of the typical diffraction peaks observed at 2θ=30.24, 35.66, 43.46, 53.74, 57.27, 62.98, 64.88, 69.68, 74.30, 77.39, and 86.70 correspond to the primary diffraction plane of the (220), (311), (400), (422), (511), (440), (531), (620), (622), (444) and (642) planes of the respectively [10]. The mean crystalline size of PANI-nFe3O4 (50%) and (100%) nanocomposites is 20.05 nm and 21.25 nm respectively. This result indicates that nFe 3O4 nPs were embedded in PANI matrix. The peak intensity of crystalline nFe 3O4 nPs gradually decreases with decreasing the amount of iron present in the system. Antimicrobial Activity. Fig.5 shows the antibacterial photographs of pure PANI and PANI-nFe3O4 nanocomposites the antibacterial assay was used to determine the growth inhibition of bacteria. . In EColi bacteria zone of inhibition for pure PANI is 10±0.2 mm and the nanocomposites 50% and 100% the zone of inhibition for E-Coli bacteria are 11±0.4 and 14±0.3 respectively. Compare the growth and zone of inhibition of E-Coli bacteria for pure PANI and nanocomposites which this parameter is MMSE Journal. Open Access www.mmse.xyz

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increased with adding nFe3O4 nPs [15]. For this growth and zone of inhibition changes are confirmed the pure PANI and nFe3O4 nPs are interact with each other. And similar changes were appeared at staphylococcus aureus bacteria for zone of inhibition value for pure PANI and PANI-nFe3O4 nanocomposites.

(a)

(b)

(c)

(d)

(e)

(f)

Fig. 5. Antibacterial activity photograph of pure PANI and PANI-Fe3O4 (50%, 100%) nCs, pure PANI (a) Staphylococcus aureus (b) E coli, PANI-Fe3O4 (50%) (c) Staphylococcus aureus (d) E coli and PANI-Fe3O4 (100%) (e) Staphylococcus aureus (f) E coli. Summary. In summary, the synthesized polyaniline was adding the monomer aniline and oxidation agent ammonia peroxydisulphate (APS) by using chemical oxidative polymerization The polyaniline nanocomposites reinforced with different nFe3O4 nPs loading levels have been successfully prepared by using mechanical mixing method. The nanostructure and chemical bonding state of the nFe 3O4 nPs modified PANI hybrids nanocomposites were systematically investigated using Fourier transform infrared (FTIR) spectra, UV-Vis spectra, X-ray diffraction spectroscopy, and antibacterial activity. FTIR spectroscopy of powdered samples mixed with potassium bromide and then pressed in pellets reveals only small changes in the PANI, viz., these nanoparticles were successfully incorporated in PANI, using a physical process with minimum risk of chemical contamination. The functional group of PANI-nFe3O4 nanocomposites were analysis the Fe-O-Fe stretching vibration is gradually changed the peak intensity is increased with adding the Fe nanoparticles which this changes clearly explain the PANI and Fe nanoparticles highly interact for this simple method. UV-Vis and XRD analysis gave information towards the formation of pure PANI, PANI-nFe3O4 nanocomposites.

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The antibacterial activity confirmed for this nanocomposites materials are very useful in medical application. References [1] Lei Li, Abdul-Rahman O. Raji, Huilong Fei, Yang Yang, Errol L. G. Samuel and James M. Tour, Nanocomposite of Polyaniline Nanorods Grown on Graphene Nanoribbons for Highly Capacitive Pseudocapacitors, ACS Appl. Mater. Interfaces 2013, 5, 6622-6627. [2] Joanne D. Kehlbeck, Michael E. Hagerman, Brian D. Cohen, Jennifer Eliseo, Melissa Fox, William Hoek, David Karlin, Evan Leibner, Emily Nagle, Michael Nolan, Ian Schaefer, Alexandra Toney, Michael Topka, Richard Uluski and Charles Wood, Directed Self-Assembly in LaponiteCdSe-Polyaniline Nanocomposites, Langmuir 2008, 24, 9727-9738. [3] Muthiah Thiyagarajan, Lynne A. Samuelson, Jayant Kumar and Ashok L. Cholli, Helical Conformational Specificity of Enzymatically Synthesized Water-Soluble Conducting Polyaniline Nanocomposites, J. AM. CHEM. SOC. 2003, 125, 11502-11503. [4] Dan Ping Wang and Hua Chun Zeng, Nanocomposites of Anatase-Polyaniline Prepared via SelfAssembly, J. Phys. Chem. C 2009, 113, 8097-8106. [5] Jun Yang, Jun-Xiong Wu, Qiu-Feng Lu and Ting-Ting Lin, Facile Preparation of LignosulfonateGraphene Oxide-Polyaniline Ternary Nanocomposite as an Effective Adsorbent for Pb(II) Ions, ACS Sustainable Chem. Eng. 2014, 2, 1203-1211. [6] Hesham Ramzy Tantawy, D. Eric Aston, Jacob R. Smith and Jeffrey L. Young, Comparison of Electromagnetic Shielding with Polyaniline Nanopowders Produced in Solvent-Limited Conditions, ACS Appl. Mater. Interfaces 2013, 5, 4648-4658. [7] Una Bogdanovic, Vesna Vodnik, Miodrag Mitric, Suzana Dimitrijevic, Sreco D. Skapin, Vojka Zunic, Milica Budimir and Milovan Stoiljkovic, Nanomaterial with High Antimicrobial Efficacy Copper-Polyaniline Nanocomposite, ACS Appl. Mater. Interfaces 2015, 7, 1955-1966. [8] Li Li, Zong-Yi Qin, Xia Liang, Qing-Qing Fan, Ya-Qing Lu, Wen-Hua Wu and Mei-Fang Zhu, Facile Fabrication of Uniform Core-Shell Structured Carbon Nanotube-Polyaniline Nanocomposites. J. Phys. Chem. C 2009, 113, 5502-5507. [9] Fei Chen and Peng Liu, Conducting Polyaniline Nanoparticles and Their Dispersion for Waterborne Corrosion Protection Coatings, ACS Appl. Mater. Interfaces 2011, 3, 2694-2702. [10] C.G. Wu, D. C. DeGroot, H. O. Marcy, J. L. Schindler, C. R. Kannewurf, Y.J. Liu, W. Hirpo and M. G. Kanatzidis, Redox Intercalative Polymerization of Aniline in V2O5 Xerogel. The Postintercalative Intralamellar Polymer Growth in Polyaniline-Metal Oxide Nanocomposites Is Facilitated by Molecular Oxygen, Chem. Mater. 1996, 8, 1992-2004. [11] Mohd Omaish Ansari, Mohammad Mansoob Khan, Sajid Ali Ansari, Kati Raju, Jintae Lee and Moo Hwan Cho, Enhanced Thermal Stability under DC Electrical Conductivity Retention and Visible Light Activity of Ag-TiO2-Polyaniline Nanocomposite Film, ACS Appl. Mater. Interfaces 2014, 6, 8124-8133. [12] Lei Wang, Xi-Lin Wu, Wei-Hong Xu, Xing-Jiu Huang, Jin-Huai Liu and An-Wu Xu, Stable Organic-Inorganic Hybrid of Polyaniline-Îą-Zirconium Phosphate for Efficient Removal of Organic Pollutants in Water Environment, ACS Appl. Mater. Interfaces 2012, 4, 2686-2692. [13] Yan Qiao, Shu-Juan Bao, Chang Ming Li, Xiao-Qiang Cui, Zhi-Song Lu and Jun Guo, Nanostructured Polyaniline-Titanium Dioxide Composite Anode for Microbial Fuel Cells, ACS NANO VOL. 2 NO. 1 113-119 2008.

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[14] Minkyu Kim, Sunghun Cho, Jooyoung Song, Suim Son, and Jyongsik Jang, Controllable Synthesis of Highly Conductive Polyaniline Coated Silica Nanoparticles Using Self-Stabilized Dispersion Polymerization, ACS Appl. Mater. Interfaces 2012, 4, 4603-4609. [15] Selcuk Poyraz, Idris Cerkez, Tung Shi Huang, Zhen Liu, Litao Kang, Jujie Luo and Xinyu Zhang, One-Step Synthesis and Characterization of Polyaniline Nanofiber- Silver Nanoparticle Composite Networks as Antibacterial Agents, ACS Appl. Mater. Interfaces 2014, 6, 20025-20034. Cite the paper N. Dhachanamoorthi, L. Chandra, P. Suresh, K. Perumal (2017). Facile Preparation and Characterization of Polyaniline-iron Oxide Ternary Polymer Nanocomposites by Using “Mechanical Mixing” Approach. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.41.37.672

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Experimental Investigation of Static Mechanical Properties of Epoxy Based Glass, Carbon & Sisal Woven Fabric Hybrid Composites 48 M. Arulkumar1, K.S. Rajeshwaran2, G. Sathish3 1 – Assistant Professor, Sri Venkateswara College of Engineering, Sriperumbudur, India 2– UG Student, Sri Venkateswara College of Engineering, Sriperumbudur, India DOI 10.2412/mmse.37.66.392 provided by Seo4U.link

Keywords: synthetic fiber, natural fiber, Epoxy, biodegradable, hand layup method, ASTM standards.

ABSTRACT. In recent years, composite materials widely involved replacing the metals to increase the strength at minimal weight. Synthetic fiber reinforced polymer composites are widely used many application like aircraft, automobile etc. Due to increasing demand for the synthetic fiber, because of its light weight and easily biodegradable, Natural fiber are involved in achieving good strength to weight ratio. In present work sisal fiber reinforced polymer composite SFRP was used to replacing the two synthetic composite such as carbon fiber reinforced polymer composite CFRP and glass reinforced polymer composite GFRP. All laminates are fabricated by using hand layup method. The static mechanical properties of epoxy based SFRP, GFRP, CFRP and their hybrids laminates are experimentally evaluated as per ASTM standards and reported.

Introduction. Investigated the mechanical properties of sisal, jute and glass fiber reinforced polyester composites observed that the addition of glass fiber into jute fiber composite resulted in maximum tensile strength and that jute and sisal mixture composites sample is capable having maximum flexural strength and maximum impact strength was obtained. [4]. The variation of tensile strength, flexural strength and compressive strength of epoxy based sisal-glass hybrid composites have observed that 2 cm fiber length hybrid composites showed maximum optimal tensile, flexural and compressive strength than 1 and 3 cm. The effect of alkali treated hybrid composites showed higher strength than untreated composites [2]. Increase in NaOH concentration worsens the tensile properties of the natural fiber and also higher concentration enhances the surface characteristics of the fiber by removing the waxy layer from the surface and the fiber matrix interfacial adhesion. So 6% NaOH is the optimum concentration which provides acceptable fiber strength and surface characteristics [8]. The application of composites in structural facilities is mostly concentrated on increasing the strength of the structure with the help of artificial fibers and does not address the issue of sustainability of these raw materials used for strengthening purposes [6]. The composite with 50% sisal-glass fibre and 50% resin combination has maximum tensile strength and that the breaking load of sisal-glass fibre reinforced composite is 1.10 times higher than sisalcoir-glass fibre reinforced composite and 1.33 times higher than coir-glass fiber reinforced composite. The percentage elongation of coir-glass fiber reinforced composite is found as higher than the other composites and hence it may have more ductile property in nature [1]. In the present work we are going compare the static mechanical properties of glass fiber, carbon fiber and sisal fiber in the form reinforced polymer composite laminates. We made the laminates in stacking sequence form of glass- sisal- glass sisal –glass (GSGSG), sisal- glass- sisal- glass- sisal (SGSGS), carbon- sisal- carbon- sisal- carbon (CSCSC) and carbon- sisal- glass- sisal- carbon (CSGSC). Four different combination hybrid composite laminates were prepared through hand lay© 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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up techniques. Then the laminates are tested as per ASTM standards for polymer composites. The results of various mechanical properties are reported and tabulated. Fabrication of Composite Laminates. E-glass, Carbon and Sisal are taken in the form of woven fabric. Sisal is natural fiber it undergoes alkali treatment to increase the bonding characteristics. Alkali treatment. Woven fabric sisal layers of size 300 X 300 mm are taken. Total seven layers of sisal used for entire study. It can be immersed in 6.25% NAOH solution over 24 hours at room temperature. Then after the completion of the process, the sisal layers mats washed with distilled water. After washing woven fabric sisal layers can be dried in room temperature for 24 hours.

Fig. 1. Surface Treatment for Sisal fibers.

Fig. 2. Hand layup technique. Hand layup method. Woven fabric hybrid composite laminates considered for investigation were fabricated by hand layup technique. Epoxy resin LY556 premixed and homogenized with hardener HY951 in the ratio of 9:1 by volume was used as matrix. To ensure a uniform thickness for all MMSE Journal. Open Access www.mmse.xyz

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laminates, an aluminum dam of size of 300 x 300 x 3 mm3 was used between the match plates. To avoid sticking of epoxy with aluminum dam polyethylene sheets were used. In silicon spray were to make easy separation of laminates with polyethylene sheets and aluminum dam. The various steps involved to fabricate the hybrid composite laminates are, An aluminum dam of size of 300 x 300 x 3 mm3 was taken. The polyethylene sheet placed over the aluminum dam as size more than that of aluminum dam for easy separation. Silicon spray is sprayed over the polyethylene sheet for easy separation of composite laminates from the dam. Mixed matrix can be brushed over the silicon sprayed polyethylene sheet. First layer of hybrid composite can be placed over the matrix filled dam. Then roller was used to make equal distribution of matrix in the layers. Again the mixed matrix can be brushed over the surface of first layer. Second layer of hybrid composite can be placed over matrix filled first layer. Then roller was used to make equal distribution of matrix in the layers. Repeat the same steps until the completion required laminates size or combination. Final step place the silicon sprayed polyethylene sheet over final layer surface of composite laminates. Then aluminum dam placed over the sheet. Then composite laminates placed over compression molding machine for 24 hours at a pressure of 350psi. The process was repeated for all four combination of hybrid composite laminates. Evaluation of Mechanical Properties. Prepared hybrid composite laminates of different combination were taken evaluation of mechanical properties. The mechanical properties are evaluated as per the ASTM standards. Specimen prepared for different mechanical test like tensile test, flexural test and impact test. Tensile test. The standard for tensile testing is ASTM D638. The prepared specimen is loaded onto the machine and fixed into the cross heads and the load is applied gradually applied.

Fig. 3. Tensile test specimen. Flexural test. The ASTM standard for flexural testing is D790, it is to have a rectangular piece of dimensions 12.7mm x 64mm.

Fig. 4. Flexural test specimen. Impact test. The ASTM standard for impact testing is ASTM D256, the dimensions of the specimen being, 12.7mm x 63.5mm with a Vee notch at a distance from 31.8 mm from one of the ends. The Vee notch is to be at depth of 2.54 mm.

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Fig. 5. Impact test specimen. Result and Discussion. After the specimens were prepared as per the ASTM standards various mechanical test are done to evaluate their properties. Tensile test results. It shows that the CSCSC have more tensile strength when compared to other combination. This because of implies of more carbon fiber in this combination gives more tensile strength. Interplay of glass in between the sisal and outer layer of carbon in form of CSGSC gives more strength when to other two hybrid forms of GSGSG and SGSGS.

Fig. 6. Load vs displacement for tensile test.

Fig. 7. Stress vs strain for tensile test. Flexural test results. It shows that the sisal glass combination GSGSG and SGSGS have increased displacement at low load where else carbon sisal glass CSCSC and CSGSC combination shows less displacement at maximum load.

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Fig. 8. Load vs displacement for flexural test. Impact test results. It shows that adding more sisal layer GSGSG and SGSGS shows that maximum impact strength when compare other two combinations CSCSC and CSGSC. It clearly state adding of more natural fiber over synthetic gives more impact strength. And that impact energy of maximum content of natural fiber shows high when to least addiction of natural fiber. Interplay of glass in between the sisal and outer layer of carbon in form of CSGSC gives more strength when to other two hybrid forms of GSGSG and SGSGS.

Fig. 9. Impact strength.

Fig. 10. Impact energy.

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Summary. This work shows that successful fabrication of Carbon- Sisal - Glass Fiber Reinforced composites with different fiber composition is possible by using simple hand lay-up technique. It has been noticed that the mechanical properties of the various hybrid composites laminates such as tensile strength, flexural strength, and impact strength of the composites are greatly influenced by the fiber composition. In Tensile Test, CSCSC composition yielded the highest tensile strength then the other composition. In Flexural Test, CSCSC composition yielded the highest flexural strength and flexural modulus. In Impact Test, SGSGS composition yielded the highest impact energy in Joules and highest impact strength. References [1] Chaitanyan, C. and Raghuraman, S. (2013) A Study of Mechanical Properties of Sisal-Glass Reinforced Hybrid Composites. IJARSET, 6, 1-6 [2] D. Dash, S. Samanta, S.S. Gautam, M. Murlidhar, Mechanical Characterizations of Natural Fiber Reinforced Composite Materials, Advanced Materials Manufacturing & Characterization Vol 3 Issue 1, 2013. [3] Gowthami, A., Ramanaiah, K., Prasad, A.V.R., Reddy, K.H.C. and Rao, K.M. (2012) Effect of Silica on Thermal and Mechanical Properties of Sisal Fiber Reinforced Polyster Composites. Journal of Material Environment Science, 4,199-204. [4] M.Ramesh, Palanikumar K, Hemachandra Reddy K, Mechanical Property evaluation of sisal-juteglass Fiber Reinforced Polyester Composites, Composites Part B,vol48 pp.1-9, 2012. [5] Sanjeevamurthy, G.C., Rangasrinivas, G. and Manu, S. (2012) Mechanical Performance of Natural Fiber-Reinforced Epoxy-Hybrid Composites. International Journal of Engineering Research and Applications (IJERA), 2, 615-619. [6] Sen, T. and Jagannatha Reddy, H.N. (2011) Application of Sisal, Bamboo, Coir and Jute Natural. International Journal of Innovation, Management and Technology, 2, 186-191. [7] Tara Sen, H. N. Jagannatha Reddy, Application of Sisal, Bamboo, Coir and Jute Natural Composites in Structural Up gradation, International Journal of Innovation, Management and Technology, Vol. 2, No. 3, June 2011. [8] Hemant Patel, Prof. Ashish Parkhe, Dr P. K. Sharma. Mechanical behaviours of banana and sisal hybrid composites reinforced with epoxy resins. Cite the paper M. Arulkumar, K.S. Rajeshwaran, G. Sathish, M. Reddi Babu (2017). Experimental Investigation of Static Mechanical Properties of Epoxy Based Glass, Carbon & Sisal Woven Fabric Hybrid Composites. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.37.66.392

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Structural and Complex Formation of PVC – LiNO3 – CdO49 P. Karthika1, a, R. Karthigai Selvi1, P.S. Devi Prasadh2, b 1 – Research Scholars, Department of Physics, Ayya Nadar Janaki Ammal College, Sivakasi – 626 124, Tamilnadu, India 2 – Department of Physics, Dr. Mahalingam College of Engineering & Technology, Pollachi – 642 003, Coimbatore, India a – pkarthikaa@gmail.com b – psdprasadh@gmail.com DOI 10.2412/mmse.65.100.626 provided by Seo4U.link

Keywords: PVC, LiNO3, CdO, XRD, FTIR.

ABSTRACT. Solid polymer electrolyte films based on Polyvinyl Chloride (PVC) complexed with different concentrations of Lithium Nitrate (LiNO3) salt using solvent cast technique is prepared. The polymer salt complex formations are confirmed by FTIR studies. The surface morphology of polymer electrolyte is studied by XRD analysis. It provides that the electrolytes are more amorphous in nature and CdO acts as plasticizers. The composite polymer electrolytes show good thermal property, which are confirmed by DSC. This analysis provides information on the glass transition temperature of polymer electrolytes.

Introduction. Importance of polymer research focused mainly to develop the polymer electrolyte. These materials were lighter and exhibited mechanical strength. Investigation on complex formation was due to application of solid state batteries, sensors, fuel cells and electrochemical windows cellular telephones etc., However in this process, due to the use of large amount of expensive and harmful. Hence in the present invention, a simple, reliable, time saving and industrially feasible process developed for fabrication of micro – porous polymer membrane. Moreover these membranes detached from the substrate and used for Li battery applications or many other applications depending upon the type of dopant to be used. The membrane morphology was investigated by XRD analysis and complex formation by FTIR. Experimental Description. Polyvinyl chloride used without further purification for the preparation of micro porous membranes. AR/BDH grade lithium nitrate (LiNO3) used. The different composition of PVC – LiNO3 and nanofiller CdO prepared by solvent casting technique corresponding constituents in THF. After stirring, a homogeneous solution obtained and poured on to a glass plate and tetrahydrofuran allowed to evaporate in air at room temperature in dust free atmosphere. The films dried for another one day to remove any trace of THF. The films were prepared. Result and Discussion XRD Analysis. X – ray diffraction was useful to examine the nature of sample, particle size analysis of mixture of phases. The amount of amorphous phase of a polymer was also important because the electrical transport occurred through atmosphere phase rather then the crystalline nature. XRD of pure PVC revealed the amorphous nature of the polymer electrolyte. [1]. It was evident that XRD pattern of PVC, Bragg’s peak at 9.5°,22.5° and 28.5° for its partially crystalline nature. When concentration of CdO increased, amorphous character of the sample also increased and it inferred by © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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shifting of peaks, increasing of intensity and narrowing of peak in this system. In Fig.1, the peak at 22.5Â° for PVC shifted to 24Â° for PVC - LiNO3 system similarly the same for other systems. Appearance of shifted peaks confirmed the complexation in polymer electrolytes.[3]. The composite polymer electrolytes exhibited only broad peak, which was the typical characteristics of atmorphous materials. The increase in atmosphere phase supported conductivity.[2]. The d â&#x20AC;&#x201C; spacing for the system calculated from diffractrogram. The d- spacing for PVC is 0.42 AÂ° and 3.66 AÂ° for PVC LiNO3 â&#x20AC;&#x201C; CdO(10 Wt %). It was noticed that the d- spacing increased with the increasing voncentration of CdO. This result provided that the polymer electrolytes were more amorphous in nature as CdO served like a plasticizer [3].

Fig. 1. XRD plots for (c) PVC + LiNO3 + CdO2 (3 Wt %), (d) PVC + LiNO3 + CdO2 (5 Wt %), (e) PVC + LiNO3 + CdO2 (8 Wt %) and (f) PVC + LiNO3 + CdO2 (10 Wt %). FTIR Analysis: It was an efficient technique to analyse the loads structural changes in polymer. Fig 2.1 showed the FTIR spectrum for pure PVC and was agreement with that reported by early investigations. The C- Cl stretching bonds of PVC occurred normally at â&#x2C6;? (692.47 cm-1), đ?&#x203A;˝ (639.53 cm-1) and Ĺ&#x2014; (615.31 cm-1) and sensitive to crystalline nature, stereo regularity and configuration of the polymer chain.[1]. In Fig.2, it noticed that the peak 692.47 cm-1 of PVC cording to C â&#x20AC;&#x201C; Cl stretching disappeared in the spectrum of PVC â&#x20AC;&#x201C; LiNO3.CH2 rocking of PVC at 692.47 cm-1 shifted to 960.58 cm-1 in PVC â&#x20AC;&#x201C; LiNO3. The wave numbers 1435.09 cm-1 and 1332.88 cm-1 of PVC corresponding to CH2 wagging and deformation of C â&#x20AC;&#x201C; H of CHCl disappeared in the spectrum of PVC â&#x20AC;&#x201C; LiNO3. Stretching of C- H of CHCl at 2972.40 cm-1 and asymmetric stretching of C â&#x20AC;&#x201C; H of CH2 at 2910.68 cm-1 remains at the same position in PVC â&#x20AC;&#x201C; LiNO3. C â&#x20AC;&#x201C; C stretching occurred at 1066 cm-1 shifted to 1064.74 cm-1 in PVC â&#x20AC;&#x201C; LiNO3. Further, the C-Cl vibration modes of PVC had undergone broadening, disappearance and intensity reduction while adding LiNO3.The vibration mode 651 cm-1 of NO2-(Nitrite anion) of LiNO3[2] appeared with the shift as 1631.83 cm-1 in PVC â&#x20AC;&#x201C; LiNO3.This confirmed that there was good complex formation between PVC and LiNO3. MMSE Journal. Open Access www.mmse.xyz

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DSC Analysis: From Fig. 3 it was seen that PVC - LiNO3 – CdO (3 Wt %), the endothermic peaks started to appear and the subsequent exothermic peaks found to be shifted. This indicated that the added CdO changed the thermal transition behavior of PVC – LiNO3 system. It found that there was less broader and small endothermic peak around 124.33° C and exothermic peaks at 268.62° C, 345.53° C and 536.82° C. The exothermic peaks showed a shift towards lower temperature. When compared with pure PVC – LiNO3, a positively shifted endothermic peak appeared at 100.26° C for CdO added complex. This indicated the increase in rigid nature of the complex PVC – LiNO3 due to the addition of 3 Wt % of CdO. Degradation found to be started at 268.62° C. It indicated the enhancement of thermal stability due to addition of CdO.

Fig. 2. FTIR Spectrum for pure PVC – LiNO3.

Fig. 3. DSC plot for pure PVC – LiNO3 – CdO2 (3 Wt %). MMSE Journal. Open Access www.mmse.xyz

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Summary. The samples were prepared using solvent casting technique. In order to understand the role of nanofiller on the thermal and the electrical properties, the nanofiller of different concentration of CdO added to the PVC-LiNO3 complex and nanocomposite polymer electrolyte prepared using the same solution casting technique. The complex formation of the solid polymer electrolyte has confirmed through the FTIR studies.XRD study also ascertains the complexation between the salt and heteroaction of polymer. Appearance of shifted Bragg’s peaks in complex confirm the complexation in polymer electrolyte which increases in d- spacing, proves that the electrolytes are more amorphous in nature and CdO2 acts as a plasticizer. DSC studies reveal that the crystallinity of PVC reduces due to the addition of the LiNO3.The addition of CdO2 leads to the change in endothermic /exothermic reaction. References [1] S.Rajendran, Shanker Babu and K.Renuka Devi, “Ionic conduction behavior in PVC – PEG blend polymer electrolytes upon the addition of TiO2”, Ionics, Vol. 15, 2009, pp. 61-66. doi: 10.1007/s11581-008-0222-3 [2] Palanisamy Vickraman, Vanchiappan Aravindan, Yan-Sung Lee, “Lithium ion transport in PVC/PEG 2000 blend polymer electrolytes complexed with LiX (X= ClO 4 -, BF4- and CF3SO3-)”, Ionics, Vol. 15, 2009, pp. 433- 437. doi:10.1007/s11581-009-0387-4 [3] S.Ramesh and A.K.Arof, “A study incorporating nanosized silica into PVC-blend – based polymer electrolytes for lithium batteries”, Journal of Materials Science, Vol. 44, 2009, pp. 64046407. doi :10.1007/s10853-009-3883-z [4] G P Pandey, S A Hashmi and R.C Agarwal, “Experimental investigations on a proton conducting nanocomposite polymer electrolyte”, Journal of Physics D: Applied Physics, Vol. 41, 2008, pp. 0554409 (6pp). doi: Published 14 February 2008 [5] S.Ramesh and A.k.Akof, “Ionic conductivity studies of plasticized poly (vinyl chloride) polymer electrolytes”, Materials Science Engineering B, Vol. 85, No.1, 2001, pp. 11-15. doi: 6 August 2001 Cite the paper P. Karthika, R. Karthigai Selvi, PS Devi Prasadh (2017). Structural and Complex Formation of PVC – LiNO3 – CdO, Vol 9. Doi 10.2412/mmse.65.100.626

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Investigation of Surface Texture Generated by Friction Drilling on Al2024-T650 M. Boopathi1, S. Shankar2, T.C. Kanish3, a 1 – School of Mechanical Engineering, VIT University, Vellore - 632014, India 2 – Department of Mechatronics Engineering, Kongu Engineering college, Perundurai - 638 052, India 3 – Centre for Innovative Manufacturing Research, VIT University, Vellore - 632014, India a – tckanish@vit.ac.in DOI 10.2412/mmse.1.19.706 provided by Seo4U.link

Keywords: frictional drilling, Al2024-T6, surface topography, optical micrographs, scanning electron micrographs.

ABSTRACT. Friction drilling is a nontraditional hole-making process in which, a rotating conical tool uses the heat generated by friction to soften and penetrate a thin workpiece and create a bushing without generating chips. During friction drilling most of the frictional heat is retained in the tool-workpiece interface. The effect of frictional heating is relatively prominent; this causes excessive temperatures in the workpiece and results in undesired material damage and improper bushing formation. To overcome these issues, this study investigates the surface texture generated from friction drilling process to characterize the behaviour of friction drilling on Al2024-T6 material. The surface roughness and integrity are of prime importance for any machined components in terms of aesthetics, tribological considerations, corrosion resistance, subsequent processing advantages, fatigue life improvement as well as precision fit of critical mating surfaces. In this study, in addition to the surface roughness measurement, optical microcopy and Scanning Electron Microscopy (SEM) have been carried out to gain insight into the friction drilled surface. Obtained results from the microstructures depict that the development of the microstructures are affected by the magnitude of the friction forces and the heat produced during the friction drilling process. It is also found that from the micrographs there is no direct micro-structural evidence for melting of work-material in friction drilling.

1.0 Introduction. In general, more than 40% of material removal processes is drilling [1, 2]. During the traditional drilling process, it is found that chips coherence phenomenon will cause poor hole surface [3]. To solve this issues, researchers have developed a new drilling process called "Friction drilling". Friction drilling is a renewable process in which material is not cut but formed as collar and bush. During the process, the heat developed due to tool work piece interface melts the material and the axial force takes care of the rest of the job. The material is plunged into the top and bottom of the workpiece. The top is called the collar and bottom the bush. The thickness of the bushing is usually two to three times as the original workpiece. This leaves enough surface area for threading. In the past few years, many researchers have studied friction drilling process in the aspects of thermo mechanical changes using finite element methods [4,5], tool wear monitoring [6,7] and experimental investigations [8-11]. From the literature, it is found that, only very few works have been published on the microscopic analysis of surface textures generated during friction drilling process[12,13]. They analysed the process mechanism from macroscopic point of view using the roughness profiles. The micro structural analysis was carried out for limited materials like stainless steel, titanium and few aluminium alloys only. Recently, aluminium grade Al2024T6 has been widely used in automotive and aerospace applications due to its excellent mechanical properties. Hence, this paper presents the analysis of surface texture generated during friction drilling process using surface roughness profiles. In addition to the surface roughness measurement, optical microcopy and Scanning Electron

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Microscopy (SEM) have been carried out to gain insight into the friction drilled surface and microstructural alterations on Al2024T6 material. 2.0 Experimental details 2.1 Material used In this study Al 2024-T6 was used in the experiments, due its high strength and low corrosion resistance. The thicknesses of the specimens were 2 mm. The chemical composition of the material is given in Table 1. Table 1. Chemical composition of 2024-T6 aluminum alloy. El.

Wt%

3.8-4.9

1.2-1.8

0.3-0.9

Max 0.1

Max 0.5

Max 0.15

Max 0.25

Remaining

2.2 Experimental setup and Selection of process parameters A CNC vertical milling machine was used for the friction drilling of Al2024T6 material. The photographic view of experimental setup is depicted in Fig. 1.

CNC Machine Spindle

Friction Drilling Tool Al2024-T6 Workpiece

Fixture

Fig. 1. Friction drilling experimental setup. The experiments were planned using the Taguchi design of experiments technique. The process parameters and their levels were selected from pilot experiments and literature. Experiments were planned based on the Taguchi L9 orthogonal array with three levels of process variables as shown in Table 2. Table 2. Process parameters selected and their levels. Notation

Process parameters

Unit

A B

Spindle Speed Feed rate

RPM mm/min

1 930 0.01

Levels 2 2270 0.02

3 4540 0.03

3.0 Results and Discussions 3.1 Measurement of surface finish In the present work, the response variable is considered as average surface roughness (Ra) of the friction drilled surfaces. These surface finish measurements were carried out using Mahr brand MMSE Journal. Open Access www.mmse.xyz

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surface roughness tester equipment with martalk instrument. The measured surface roughness for all the nine experiments values are shown in Table 3. Example of measured surface finish after the friction drilling (at A3, B1) is shown in Fig. 2.

Fig. 2. An example of measured surface roughness profile (Expt. no. 3) Table 3. Experimental matrix (L9) and the output response Ra. Expt. No. 1 2 3 4 5 6 7 8 9

A (RPM) 930 2270 4540 930 2270 4540 930 2270 4540

B (mm/min) 0.01 0.01 0.01 0.02 0.02 0.02 0.03 0.03 0.03

Ra (Âľm) 1.1092 1.7968 0.7662 1.8390 1.1732 0.8502 1.4500 1.5402 0.8702

To characterize the surface obtained by the friction drilling process on Al2024-T6 material, the surface roughness profiles alone is not enough to reflect the interaction of process parameters. Therefore the corresponding optical micrographs and SEM micrographs of the workpiece surfaces were also studied and reported. 3.2 Optical Micrographs Optical microscopic images of the friction drilled finished surfaces are shown in Fig. 3. It is quite clear from Fig. 3 (a) that the plastic deformation with surface lamination are present and it exhibits thin platelets of aluminum that were removed. At higher rotational speeds, these marks have been slightly removed and replaced during the friction drilling process as shown in Fig. 3 (b, c). It is due to higher speed and lower feed rate the temperature effect arranges the lay lines to become smoother and equally spaced. Normally, friction drilling process causes surface depositions throughout the surface contact. Due to the temperature generated between the tool workpiece contact, the material is being squeezed and spread over throughout the inner surface. The speed decides the uniformity of the deposition which is evident from the Fig. 3 (a-c). The surface micrograph obtained through optical microscopy does not reveal much information at micro level. In order to obtain fine surface texture details at micro and nano level, SEM techniques were employed and the results are presented in the subsequent sections.

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(a) (b) (c) Fig. 3. Optical microscopic image (200X) of the surface texture generated by;(a) Rotational speed = 930 RPM, Feed rate = 0.03 mm/min; (b) Rotational Speed = 2270 RPM, Feed Rate = 0.02 mm/min, (c) Rotational Speed = 4540 RPM, Feed Rate = 0.01 mm/min. 3.3 Scanning Electron Micrographs To obtain the SEM images Carl Zeiss make FESEM-Supra 55 instrument was used. To gain insight into the friction drilled surface, SEM images were obtained and are shown in Fig. 4. From the Fig.4(a), the damages to the interior surface of the friction drilled hole in Al2024T6 is evident. It is found that in Fig 4(a) more plastic deformation with surface de-laminations are present. Lower speeds provide lower tool rotation; it gives sufficient time for the deposition of material in the inner surfaces. During higher speed tool rotations, the material spreads uniformly and is squeezed out immediately. This will enhance the surface texture quality and will exhibit a smooth bore surface finish as shown in Fig.4 (b,c). It is also found from the SEM micrographs that there is no direct micro-structural evidence for melting of work-material in friction drilling.

(a) (b) (c) Fig. 4. SEM Micrographs (1000X) of the surface texture generated by;(a) Rotational speed = 930 RPM, Feed rate = 0.03 mm/min; (b) Rotational Speed = 2270 RPM, Feed Rate = 0.02 mm/min, (c) Rotational Speed = 4540 RPM, Feed Rate = 0.01 mm/min. Summary. Based on the experimental investigations on friction drilling process and the results, the following conclusions were drawn: i) Friction drilling process produces better surface finish on Al2024T6 with the surface finish (Ra) value of 0.7662 Âľm at the following cutting conditions: Spindle speed (A3)= 22V; Feed rate (B1) = 1.5 mm. ii) The Optical microscopy/Scanning Electron Microscopy analysis reveals that the recrystallization of the Al2024T6 material was not observed because of the short time period of high temperature.

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iii) It is observed from the SEM images, there is no direct micro-structural evidence for melting of work material in friction drilling. Acknowledgements. Authors thank the VIT management for providing seed money to develop the friction drilling experimental setup at Advanced material processing lab. References [1] A.H. Streppel, H.J.J. Kals, Flow drilling: A preliminary analysis of a new bush-making operation. CIRP Annals-Manufacturing Technology, 1983, 32(1), 167-171. [2] E. Brinksmeier, Prediction of tool fracture in drilling, Ann. CIRP. 1990, 39, 97–100. [3] J.L. Cantero, M.M. Tardio, J.A. Canteli, M. Marcos, M.H. Miguelez, Dry drilling of alloy Ti– 6Al–4V, International Journal of Machine Tools and Manufacture, 2005, 45(11), 1246-1255. [4] S.F. Miller, A.J. Shih, Thermo-mechanical finite element modeling of the friction drilling process, Journal of Manufacturing Science and Engineering, 2007, 129(3), 531-538. [5] P. Krasauskas, Experimental and statistical investigation of thermo-mechanical friction drilling process, Mechanics, 2012, 17(6), 681-686. [6] S.F. Miller, P.J. Blau, A.J. Shih, Tool wear in friction drilling, International Journal of Machine Tools and Manufacture, 2007, 47(10), 1636-1645. [7] S.M. Lee, H.M. Chow, F.Y. Huang, B.H. Yan, Friction drilling of austenitic stainless steel by uncoated and PVD AlCrN-and TiAlN-coated tungsten carbide tools, International Journal of Machine Tools and Manufacture, 2009, 49(1), 81-88. [8] M.T. Kaya, A. Aktas, B. Beylergil, H.K. Akyildiz, An Experimental Study on Friction Drilling of ST12 Steel, Transactions of the Canadian Society for Mechanical Engineering, 2014, 38(3), 319329. [9] S.F. Miller, J. Tao, A.J. Shih, Friction drilling of cast metals, International Journal of Machine Tools and Manufacture, 2006, 46(12), 1526-1535. [10] M. Boopathi, S. Shankar, S. Manikandakumar, R. Ramesh, Experimental investigation of friction drilling on brass, aluminium and stainless steel. Procedia Engineering, 2013, 64, 1219-26. [11] D. Biermann, Y. Liu, Innovative flow drilling on magnesium wrought alloy AZ31, Procedia CIRP, 2014, 18, 209-214. [12] S.F. Miller, A.J. Shih, P.J. Blau, Microstructural alterations associated with friction drilling of steel, aluminium and titanium, Journal of Materials Engineering and Performance, 2005, 14(5), 647653. [13] H.M. Chow, S.M. Lee, L.D. Yang, Machining characteristic study of friction drilling on AISI 304 stainless steel, Journal of materials processing technology, 2008, 207(1), 180-186. Cite the paper M. Boopathi, S. Shankar, T.C. Kanish (2017). Investigation of Surface Texture Generated by Friction Drilling on Al2024-T6. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.1.19.706

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Mechanical Properties of Natural Fiber Sandwich Composite: Effect of Core Layer 51 M. Rajesh1, T.C. Kanish1,a 1 – School of Mechanical Engineering, VIT University, Vellore - 632014, India a – tckanish@vit.ac.in DOI 10.2412/mmse.43.73.809 provided by Seo4U.link

Keywords: natural fiber, weaving, mechanical properties, polymer.

ABSTRACT. In recent years, due to awareness of environmental system researchers are concentrated to developed natural fiber composite and replace with conventional material for low and medium load application. In this paper, an experimental investigations are made to analyse the mechanical properties on influence of core layers in sandwich composite. Three different weaving patterns are used as core layer namely plain, basket and twill. It has been fabricated by keeping stiff glass fabric as facing layer and relatively weak sisal natural fabric as core layer. The investigations made on sandwich composite reveals composite with plain woven sisal fabric as core layer gives higher flexural properties compared to composite with basket and twill woven fabric as core layer. Fracture surface of tensile and flexural specimens are analyzed using scanning electron microscope to understand the fracture behaviour of the sandwich composites.

Introduction. Last few decades, due to awareness of environmental and health issue, natural fiber based composites are recommended for industrial application, aerospace, automotive, civil, etc. [1]. Joshi et al. [2] analyzed the major advantages of natural fiber composite in automotive application and found that replace of light-weight natural fiber composites increases the fuel efficiency. Most of the researchers have reported the mechanical properties of natural fiber composite, by reinforcing them in short form random orientation in the matrix [3,4]. Major drawback associated with random oriented short fiber reinforcement in the polymer matrix is poor stress transfer due to amorphous nature which leads to fail composite early with lower strain rate. Alavudeen et al.[5] compared the mechanical properties of woven and short fiber reinforced banana/kenaf polyester composites. they found that woven composite enhances the mechanical properties of composites compared to composite with random oriented short fiber reinforcement. It is due to poor stress distribution in the random oriented composite under loading. Similar observation has been found by Sastra et al. [6]. They found that woven arengapinnata fiber-epoxy composite enhances the mechanical properties of composites compared to short fiber random oriented composites. Even through woven natural fiber composites enhance the properties of composites compared to random oriented short fiber composite, it is important to improve the properties of composites for medium load application. For that, researchers are hybridized natural fiber with synthetic fiber. This enhances the properties of composites. Harish et al. [7] studied the mechanical properties of coir and glass epoxy composites. Results reveal that hybrid composite improves mechanical properties compared to individual coir and glass fiber reinforced composite. Prachayawarakorn et al. [8] investigated the mechanical properties of thermoplastic cassava starch composites by adding jute and kapok fibers. Reinforcement of fiber in the thermoplastic cassava enhances the mechanical properties of composites due to formation of new hydrogen bond. Ramesh et al. [9] analysed layering effect on

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mechanical properties of glass-sisal-jute fiber. They found that mechanical properties of composites influenced by layer sequence. Further to improve the properties of composite material, researchers suggest the sandwich composite by keeping stiff layer as skin, weak reinforcement as core layer to enhances the properties of composite material. From the above literature survey, it is notified that most of the researchers investigated natural fiber in the polymer matrix either short or continuous woven form. It is important to analyse the sandwich composite for different applications (car outer body). The present work analyse the effect of core layer on mechanical properties. For that three different woven sisal fabrics (plain, twill and basket) have been choose. Experimental details 1.Material used In this study glass and sisal fibers are used as reinforce material in woven form. Three different woven fabrics are used as core layer namely plain, basket and twill as shown in Fig. 1. Fibers which are used in the present work are purchased from local dealers and matrix material unsaturated isophthalic polyester resin and catalyst (Methyl Ethyl Ketone Peroxide) and an accelerator (cobalt naphthenate) are purchased from Vasavibala resins Ltd., Chennai, India. 2.Preparation of Composites In this study hand-lay-up technique has been adopted to fabricate the sandwich composites. For that, initially matrix material has been prepared using unsaturated polyester resin, catalyst and accelerator with weight ratio of 10:1:1. Mould has been fabricated using stainless steel with a size of 300 mm×300 mm× 4mm. Further top and bottom portion of the mould is covered by stiff parallel steel plate. Initially known amount of matrix mixture is poured into mould cavity, followed by stiff glass fiber is placed over poured resin. Further small amount of resin has been poured over layer. Followed by natural fiber core layer is layered then stiff glass fiber mat has been placed as skin layer. At last, remaining amount of matrix mixture is poured in the mould cavity. Later top portion of mould cavity is coved by stiff parallel pate. In order to achieve uniform compression, 60 kg weight has been placed over the mould cavity for 5 hours. After allowing five hour curing composite laminates are removed from mould cavity and sized according to ASTM standard for tensile and flexural test. For tensile test ASTM D-638 standard has been used. For that specimens are prepared dog-bone shape with dimension of 127 mm×18 mm. For flexural test ASTM D-790 has been followed. Specimens are prepared with a dimension of 127mm×12.7mm×4mm. Fig. 2 depict the schematic diagram of sandwich composites fabricated in the study.

Fig. 1. Schematic diagram of sisal fiber mat used in the study. a)plain, b) basket, c) twill.

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Fig. 2. Schematic diagram of sandwich composite fabricated in the study. 3. Material Characterization The surface morphology studies have been carried out on tensile and flexural fracture specimen to understand the interfacial bonding between fiber and matrix, and fiber pull out. This has been done using Hitachi-S3400 Scanning Electron Microscopy (SEM) at 20KV accelerating voltage. Results and Discussion. Table 1 shows the influence of core layer on tensile and flexural properties of sandwich composites. One can observed from Table 1 is, nature of weaving pattern influence on mechanical properties. The results reveal that sandwich composite with basket core layer enhances the tensile properties of composites. It is due to high load carry capacity of basket weave fabric carries more load. In the case of basket weave type, gap between two yarn in the warp and weft direction is low, this reduces the stress concentration between warp and weft direction. Also yarn crimp in the warp and weft direction is always less while in the plain weave it is high. This leads to poor stress transfer. In the case of twill weave, movement of yarn in the warp direction is diagonal in nature. This also one reason, tensile properties of sandwich composite with twill core between basket core and plain core. From the tensile properties, it can be concluded that tensile modulus of sandwich composite with basket core is always higher than plain and twill core. This increases the resistance against deformation during tensile load. From the Table 1, it is observed that percentage variation of tensile properties for basket core sandwich composite always higher than flexural variation. Tensile strength of basket core sandwich composite is 14% and 9% higher than sandwich composites with plain and twill core.

Table 1. Mechanical properties of sandwich composites. Sandwich composite

Tensile properties

Flexural properties

Tensile strength

Tensile modulus

Flexural strength

Flexural modulus

(MPa)

(GPa)

(MPa)

(GPa)

Plain core

38.28±4.08

1.40±0.16

72.08±5.42

1.51±0.56

Basket core

44.35±3.18

1.48±0.38

66.54±4.65

1.50±0.35

Twill core

40.12±1.11

1.45±0.21

68.34±9.33

1.49±0.52

In the case of flexural properties, plain core sandwich composite gives higher flexural properties compared with basket and twill core. It is due to the effects of core against flexural load. In the case of plain core, composite gives more resistance against shear and bending. Higher amount of matrix material in the core layer also influences on flexural properties. This higher amount matrix has MMSE Journal. Open Access www.mmse.xyz

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viscous nature; this enhances the properties of composites. Percentage variation of plain core is 4% and 8% higher than twill and basket core. Surface morphology studies on the fractured test specimens are carried out using scanning electron microscope to understand the failure mechanism. Fig. 3a shows the tensile fracture surface of plain core sandwich composites. It reveals plain core damages the matrix due to the poor stress transfer. This reduces the interfacial adhesion between fiber and matrix. Fig. 3b shows flexural fracture surface of twill core sandwich composites. It reveals twill core layer damages the matrix due to non-uniform stress distribution between fiber and matric. It is due to diagonal nature of yarn movement in the warp direction creates non-uniform stress distribution. This leads to fail composite early. Fig. 3c reveals plain core transfer stress effectively on flexural load. It shows uniform matrix surface near fiber reinforcement. This indicates plain core increases the adhesion between fiber and matrix. Similar observation has been seen from Fig. 3d. It reveals basket core transfer stress uniformly from fiber to matrix. This eliminates the matrix damage.

Fig. 3. SEM micro structure of fracture surface. a) Tensile fracture surface of sandwich composite with plain core, b) Flexural fracture surface of sandwich composite with twill core, c) Flexural fracture surface of sandwich composite with plain core, d) Tensile fracture surface of sandwich composite with basket core. Summary. Influence of core layer of glass-sisal natural fiber sandwich composites on mechanical properties [tensile and flexural properties] have been investigated. Results depict that nature of weaving pattern affects the mechanical properties of sandwich composites effectively. Sandwich composite with basket core has higher tensile properties compared to plain core while twill core sandwich composite in between. It is due to less interlace between two yarns in the warp and weft direction. This reduces the stress concentration between two yarns during loading. Sandwich composite with plain core enhances the flexural properties of composites. It is due to higher amount of matrix in between skin layer and higher resistance against shear and bending gives better properties. References [1] Z. Dashtizadeh, K. Abdan, M. Jawaid, M.A. Khan, M. Behmanesh, M. Dashtizadeh, C. Francisco, M. Ishak, Effect of Chemical Treatment on Kenaf Single Fiber and Bio-Phenolic Resin Regarding its Tensile and Interfacial Shear Stress, Middle-East Journal of Scientific Research. 2016, 24(9), 2685-92.

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[2] S.V. Joshi, L.T. Drzal, A.K. Mohanty, S. Arora, Are natural fiber composites environmentally superior to glass fiber reinforced composites? Composites Part A: Applied Science and Manufacturing, 2004, 35(3), 371 - 376. [3] T.P. Sathishkumar, P. Navaneethakrishnan, S. Shankar, Tensile and flexural properties of snake grass natural fiber reinforced isophthallic polyester composites, Composites Science and Technology, 2012, 72(10), 1183-1190. [4] P.V. Joseph, K. Joseph, S. Thomas, Effect of processing variables on the mechanical properties of sisal-fiber-reinforced polypropylene composites. Composites Science and Technology 1999, 59(11), 1625-1640. [5] A. Alavudeen, N. Rajini, S. Karthikeyan, M.Thiruchitrambalam, N. Venkateshwaren, Mechanical properties of banana/kenaf fiber-reinforced hybrid polyester composites: Effect of woven fabric and random orientation. Materials and Design, 2015, 66, 246-257. [6] H.Y. Sastra, J.P. Siregar, S.M. Sapuan, M.M. Hamdan, Tensile properties of Arenga pinnata fiber-reinforced epoxy composites. Polymer-Plastics Technology and Engineering, 2006, 45(1), 149155. [7] S. Harish, D.P. Michael, A. Bensely, D.M. Lal, A. Rajadurai, Mechanical property evaluation of natural fiber coir composite, Materials Characterization, 2009, 60(1), 44-49. [8] J. Prachayawarakorn, S. Chaiwatyothin, S. Mueangta, A. Hanchana, Effect of jute and kapok fibers on properties of thermoplastic cassava starch composites, Materials and Design, 2013, 47, 309315. [9] M. Ramesh, K. Palanikumar K, K.H. Reddy, Mechanical property evaluation of sisal-jute-glass fiber reinforced polyester composites, Composites Part B: Engineering, 2013, 48, 1-9. Cite the paper M. Rajesh, T.C. Kanish (2017). Mechanical Properties of Natural Fiber Sandwich Composite: Effect of Core Layer. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.43.73.809

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Fabrication of Hybrid Metal Matrix Composite Reinforced With SiC/Al2O3/TiB252 S. Johny James1, a, A. Raja Annamalai2, P. Kuppan2, R. Oyyaravelu2 1 – Kingston Engineering College, Vellore, 632059, India 2 – School of Mechanical Engineering, VIT University, Vellore, 632014, India a – johnyjames2002@yahoo.com DOI 10.2412/mmse.66.73.476 provided by Seo4U.link

Keywords: Al2O3, hybrid metal matrix composite, SiC, TiB2, wear.

ABSTRACT. Looking at the need for composite materials, a trial was made to fabricate hybrid metal matrix composite. Efforts were taken to develop composite with three emerging reinforcements like SiC/Al 2O3/TiB2 and its compositions were 5%, 3% and 2% respectively. The aluminium metal matrix designed for this composite is aluminium alloy Al6061. Stir casting bottom pouring technique was used to fabricate the specimen successfully. The fabricated Hybrid metal matrix composite after various attempts was made to undergo various tests to examine its strength and property. Specimen was made from the casting and micro structural analysis was carried out using optical microscope and SEM. Results of micro structural analysis prove the existence and dispersion of reinforcements in the matrix phase.. Specimens were prepared in order to test its hardness due to the addition reinforcements. Vickers hardness test and its value which is equal to 122.13 HRC indicate elevated hardness value upto 50% when compare to the hardness value of parent alloy. Tensile specimens were prepared using wire EDM as per ASTM E8 standards. There is no considerable improvement in tensile strength due to addition of above reinforcements. Failure analysis was carried and the factors caused failure was analyzed. In order to study and understand the wear resistance property of Composite which it is mainly known for, wear test was carried out and test results proves the increase in wear resistance property of Composite in terms of frictional force and coefficient of friction.

Introduction. Requirement of engineering materials paves the way for invention of advanced materials like super alloys, ceramics, and composites. In these advanced materials Composites have distinguished properties such as increased wear resistance, high specific strength, strength-to-weight ratio, strength to cost ratio etc. This unique property finds application in aerospace, defense, marine, etc. This motivates researchers to fabricate composite with constitution of various reinforcements with aluminum matrix. The addition any one of the reinforcements like SiC, B 4C, Al2O3, ZrSiO4, TiN, and TiB2 have been carried out and in process as well. Efforts have been initiated to fabricate metal matrix using in situ salt reactions [1]. The stir casting process parameters were thoroughly examined by Pai. It has been concluded that, stir casting process is relatively simple and less expensive as compared to other processing methods [2,3]. Production of composites using stir casting process needs equal distribution of abrasive particles with the metal matrix. S. Balasivanandha Prabu “Influence of stirring speed and stirring time on distribution of particles in cast metal matrix composite”. In the present study, high silicon content aluminium alloy–silicon carbide metal matrix composite material, with 10% SiC were successfully synthesized, using different stirring speeds and stirring times.. [4]. Cast composite mainly replace steel and alloys used in aerospace, defense mainly wear resistant applications. Titanium diboride (TiB2) gives a number of advantages over traditional ceramic reinforcements such as silicon carbide (SiC) or alumina (Al2O3). But fabrication of composite reinforced with TiB2 has number of challenges [5]. During fabrication of TiB2 chances of formation of cluster is at high side. [6]. TiB2 has resistance to chemical reaction with Aluminum. The wear © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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resistance of this material is due to the lack of pull out of this material from the aluminum matrix. TiB2 composites are well known for high wear resistant property when compared to other available ceramic reinforcements [7,8].This work focuses addition of TiB 2, SiC and Al2O3 metal matrix composite. So far SiC and Al2O3 is added with Aluminum matrix but not TiB2. An objective of this study is to harvest the merits of TiB2, SiC and Al2O3.However; most of the existing research work focus on the effect of metal matrix composite with single reinforcement. The present work develops hybrid metal matrix composite. SiC and Al2O3 is widely used reinforcement for composite and it has its own elevated mechanical property. Our present work selects TiB 2 as third reinforcement because of its outstanding properties than other existing reinforcements. Experimental procedure. Silicon Carbide, Alumina and Titanium di boride of average particle size 30 micron was used to fabricate Al-SiC-Al2O3-TiB2 metal matrix composite by stir casting bottom pouring technique. The metal matrix selected for this work was Al6061. The melting of aluminium alloy was carried out in a steel crucible located inside the resistance furnace. SiC, Al2O3 and TiB2 particles were preheated at 400°C and 200°C respectively for 90 min to get better wet ability by removing the absorbed hydroxide and added gases. At this molten stage the preheated SiC, Al2O3 and TiB2 particles were added into the crucible. The reinforcement as well as matrix were stirred using mechanical stirrer. The mixed slurry was poured into the mould by bottom pouring technique. Samples were sliced using wire EDM to study the morphology of cast composite. The micro hardness test was carried out by means of Vicker’s hardness testing instrument (Matsuzawa MMT-X). The tensile test was performed using INSTRON tensile testing machine. The specimens were prepared as per ASTM-E8 standard Wear test was performed using pin-on-disc reciprocating wear testing equipment Results and Discussion Microstructure analysis. Fig1 (a, b, c, d) shows the SEM and optical image of Al6061/ SiC/Al2O3/TiB2 Composite. The SEM and optical image confirms the existence of SiC/Al2O3/TiB2 reinforcements in the metal matrix and its distribution in the metal matrix.

Fig. 1, a SEM image of SiC/Al2O3/TiB2.

Fig. 1, b SEM image of SiC/Al2O3/TiB2. CLUSTERS

Fig. 1, (c) Optical image of SiC/Al2O3/TiB2.

Fig. 1, (d) Optical image of SiC/Al2O3/TiB2.

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Cluster formation. From Fig1 (b, d) it is also observed that there is cluster of reinforcement particle in the metal matrix phase. These cluster formation is one of the main challenge in fabrication of composites using stir casting. As the cluster powders are only reinforcement, during specimen preparation by machining process like EDM, milling etc the reinforcement powders will be poured out which leads to pores. This can be clearly identified using SEM. The black pore which is seen continuously is cluster of reinforcement and the grey phase surrounded by reinforcement is aluminum matrix as shown in SEM image.. This can be prevented by varying stirring speed, holding time and improving wettability between reinforcement and metal matrix phase. Researchers may concentrate in this problem and find a solution to avoid agglomeration. Hardness test of Al6061 reinforced with SiC, Al2O3 and TiB2

Table 1. The hardness value. Diagonal(μm)

Measurement Position(mm)

Hardness

Conv. Scale

Distance

Load

7.639

-0.427

7.651

500

94.52

79.31

122.7

HRC

7.232

-0.356

7.241

500

83.43

80.44

138.1

HRC

7.549

-0.303

7.555

500

94.66

92.67

105.6

HRC

122.13

HRC

Average value

Addition of reinforcement with aluminum matrix normally increases hardness. In this work SiC, Al2O3 and TiB2 respectively which is named for high hardness was added with the metal matrix. Hardness test was carried out for a load 500gf with a dwell time of 10 seconds. Three readings were taken with standard distance of 0.5mm from every indentation to achieve reliability in results. The average hardness value is 122.13 HRC. The hardness value proves 50% increases in hardness due to the addition of SiC, Al2O3 and TiB2. It has been clearly proved that addition of reinforcements with aluminum matrix increases the hardness value. Mechanical testing. The size of each tensile specimen was 100x10x6 mm. The maximum tensile strength value of cast composite is 0.091Gpa. From table it has been concluded that there is no considerable increase in tensile strength of the cast composite specimen. The cast specimen’s strength value will be more if the amount of cluster formation has been controlled by using proper stir casting parameters.

Table 2. The tensile strength of Composite. Maximum Load

Modulus (Automatic Young's)

Proof Stress

(MPa)

0.070

29806.848

60.63

3333.81891

0.087

35429.303

72.66

3488.38568

0.091

37072.744

70.74

Weight % of reinforcements

SL.NO

Al6061/SiC-5%

2697.14594

Al2O3-3%

TiB2-2%

(N)

UTS (GPa)

Maximum value

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Fractography Fig 2(a) and 2(b) shows the SEM image of Al6061/SiC/Al2 O3/TiB2 tensile specimen after test. It has been observed from the figure that the reinforcement is evenly distributed in the continuous metal phase of the cast specimen. But a clear, strong interfacial bonding is not seen in between metal and reinforcement phase. This poor interfacial bonding decreased the strength of the composite than the parent metal.

Fig. 2. (a) Tensile fracture SEM image.

Fig. 2. (b) Tensile fracture SEM image.

The black spot seen in the image 1(d) are reinforcement clusters. The SiC, Al2O 3, TiB2 particles mix together and forms cluster. The cluster formed surface lack interfacial bonding with aluminum matrix. As this cluster formation leads to pores and poor interfacial bonding tensile test results are adverse and substantial reduction in strength of composite to 0.091Gpa. Wear test Wear test was carried to find out wear resistant property of composite for the purpose which is well known for. The table tabulates COF and FF which is 0.668, 33.483N respectively. Additions of reinforcements like SiC, Al2O3, increases wear resistance property. The hard reinforcement particles especially TiB2 and its high wear resistant property prevent the aluminium matrix from wear. Table 5. Shows the value of Cof and Frictional Force during wear test. COF

FF(N)

0.668

33.483

TEMP(Â°C) LOAD(N) 34

SPEED

Wear in um

608

128.298

Summary. Materials required to fabricate hybrid metal matrix composite was perfectly chosen and fabricated using stir casting process. Microstructure and spectrum processing shows the distribution and existence of SiC, Al2O3, and TiB2 in the metal matrix. Hardness test proves improvement of hardness value approximately 50% due to the addition of reinforcements in the metal matrix phase. Tensile test was carried out and tensile strength was measured. The low value depicts poor bonding between reinforcement and metal matrix which is clearly once again proved by fractography. Wear resistant property which is one of the peculiar properties of Composite has been achieved due to addition of three reinforcements especially TiB2 in metal matrix Al 6061. Above fabrication and tests MMSE Journal. Open Access www.mmse.xyz

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ensure the attainment of superior mechanical and tribological property of cast hybrid metal matrix composite using stir casting process. References [1] Kumar, S., Chakraborty, M., Sarma, V. S., & Murty, B. S. (2008). Tensile and wear behaviour of in situ Al–7Si/TiB 2 particulate composites. Wear, 265(1), 134-142. [2] Pai, B. C., Pillai, R. M., & Satyanarayana, K. G. (1993). Stir Cast Aluminium Alloy Matrix Composites. In Key Engineering Materials (Vol. 79, pp. 117-128). Trans Tech Publications. [3] Hashim, J., Looney, L., & Hashmi, M. S. J. (1999). Metal matrix composites: production by the stir casting method. Journal of Materials Processing Technology, 92, 1-7. [4] Prabu, S. B., Karunamoorthy, L., Kathiresan, S., & Mohan, B. (2006). Influence of stirring speed and stirring time on distribution of particles in cast metal matrix composite. Journal of Materials Processing Technology, 171(2), 268-273. [5]. Watson, I. G., Forster, M. F., Lee, P. D., Dashwood, R. J., Hamilton, R. W., & Chirazi, A. (2005). Investigation of the clustering behaviour of titanium diboride particles in aluminium. Composites Part A: Applied Science and Manufacturing, 36(9), 1177-1187. [6] Smith, A. V., & Chung, D. D. L. (1996). Titanium diboride particle-reinforced aluminium with high wear resistance. Journal of materials science, 31(22), 5961-5973. [7] Taya, M., Hayashi, S., Kobayashi, A. S., & Yoon, H. S. (1990). Toughening of a Particulate‐ Reinforced Ceramic‐Matrix Composite by Thermal Residual Stress. Journal of the American Ceramic Society, 73(5), 1382-1391. [8] Mc Murtry, C. H., Boecher, W. D. G., Seshardri, S. G., Zanghi, J. S., & Garnier, J. E. (1987). Microstructure and material properties of SiC-TiB/sub 2/particulate composites. Am. Ceram. Soc. Bull.;(United States), 66(2). Cite the paper S. Johny James, A. Raja Annamalai, P. Kuppan, R. Oyyaravelu (2017) Fabrication of Hybrid Metal Matrix Composite Reinforced With SiC/Al2O3/TiB2. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.66.73.476

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Fabrication of Aluminium Metal Matrix Composite and Testing of Its Property53 S. JohnyJames 1, a, A. Raja Annamalai1 1 – School of Mechanical Engineering, VIT University, Vellore, 632014, India a – johnyjames2002@yahoo.com DOI 10.2412/mmse.62.86.695 provided by Seo4U.link

Keywords: metal matrix composite, stir casting, tensile strength, wear, Zirconium silicate.

ABSTRACT. In this paper an attempt has been made to fabricate aluminium metal matrix composite using a newly emerging reinforcement Zirconium silicate which is also called as Zircon (ZrSiO 4). The metal matrix selected was Al6061. The composition of reinforcement with the metal matrix is 10 wt percent. Stir casting bottom pouring technique was chosen to fabricate the composite. From the cast specimen various samples were cut to study its mechanical and tribological property after the addition of reinforcement. The optical and SEM image shows the presence and dispersion of reinforcements in the metal matrix phase. The spectrum processing was carried out and the result confirms the presence of Zirconium, Silicon, oxygen and aluminium. The Vickers hardness test shows elevated hardness value due to the addition of reinforcement ZrSiO4 and its value is 101.1HRC. The tensile specimens were prepared using wire-EDM process as per ASTM-E8 standard. The tensile value reveals that there was an improvement in tensile strength of composite and its value is 0.094Gpa. Also, fractography study was done using scanning electron microscope to understand the causes of failure of specimen. Wear test was carried out on the composite using a linear reciprocating tribometer. The wear test result confirms high wear resistance due to the addition of ZrSiO4 reinforcement in aluminium matrix.

Introduction. Composites material has high stiffness and high strength, low density, improved wear resistance, etc. When designed precisely, the newly combined materials produce enhanced strength than would each individual material.The addition of ceramic particles like SiC, Al2O3, B4C, Al2O3to an aluminum based matrix does not much alter the density of material but instead it usually leads to a considerable rise in strength and modulus of composite. Alaneme, studied the mechanical behaviour of alumina reinforced with 6063 metal matrix composite developed by two step – stir casting process. AA 6063– Al2O3 particulate composites having 6, 9, 15, and 18 volume percent of reinforcement were produced..[1] Sreenivasan fabricated TiB2/Al metal matrix composites by stir casting route with 5, 10 and 15% of TiB2 and studied the wear behaviour of composite. It was observed that the wear rate was higher for the unreinforced aluminium alloy when compared to the reinforced composites. Wear rate was decreased with increasing TiB2 content in the MMC composites[2]. The composite fabricated using stircasting technique exhibit uniform distribution. Result of uniform distribution of reinforcement in the metal matrix confirm elevated mechanical behavior[3]. Also addition of reinforcements like Al2O3, SiC, TiB2 in the metal matrix improves hardness and thermal property [4]. It has been observed that, elongation decreses when the percentage reinforcement increases, but tensile and hardness value will be high[5,6]. The homogeneity of reinforcement and uniform distribution of reinforcement particles in metal matrix depend upon stir casing parameters [7].From the literature review it was noted that the most commonly used abrasive reinforcement with aluminium matrix are SiC, Al2O3, B4C and TiB2 and not much published literature on Zirconium silicate as reinforcement. Hence, in this paper an attempt has been made to fabricate aluminium metal matrix composite with Zirconium Silicate as reinforcement material and to study metallurgical, © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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tribological and mechanical behavior of developed composite material. II. Experimental Procedure The reinforcement selected for the present study was Zirconium Silicate because of its unique material property and high hardness value about 7.5-8.0 Mohs Hardness at 20°C. Zirconium silicate is highly resist corrosion by alkali materials. The average particle size of Zirconium Silicate was 35 microns.The composites were prepared with 10 wt. % of Zirconium silicate.The aluminium matrix material selected was Al6061 which supports casting process. The Zirconium Silicate particles were preheated at 450°C for 60 min to improve the wetability by removing moistureThe furnace temperature was set to 840°C to melt the aluminium alloyContinous stirring of molten aluminium at 450 rpm lead to formation of vortex. The preheated reinforments were gently added into the molten alloy upon the vortex. Both aluminium alloy and reinforcement material was held in the crucible for 7 minutes and continously being stirred inorder to gain uniform distribution of reinforcement in the matrix. Through bottom pouring arrangemnt the molten metal was poured into the die and solidified.The required test specimens for microstructure analysis, hardnes test, tensile test and wear test were cut from the cast composite using wire-EDM process. III. Results and Discussion 3.1 Micrograph and analysis The specimen for microstructure analysis was polished and the micrographs were captured using optical microscope and SEM. The microstructures have been throughly examined and found reinforcement particles were uniformly distributed in the metal matrix. Uniform distribution of reinforcement gives strength to the matrix and the same is the root cause for elevated mechanical property. Fig 1(a,b,c,d) shows the existance of reinforcement particles in the composite specimen. Few cluster formation were noticed and predicted this will cause reduction in mechanical property especially tensile strength.

Fig. 1, (a) SEM Micrograph of Al/ ZrSiO4.

Fig.1, (b) SEM Micrograph of Al/ ZrSiO4.

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AGGLOMERATION

Fig. 1, (c) Optical Micrograph of Al/ ZrSiO4.

Fig. 1, (d) Optical Micrograph of Al/ ZrSiO4.

Spectrum processing: Table 1. Elements present in the cast composite. Element

Weight%

Atomic%

1.07

1.79

Al K Si K Zr L Totals

97.69 1.01 0.24 100.00

97.18 0.96 0.07

Hardness test of Al6061 reinforced with ZrSiO4 The Vickers hardness test was carried out using (Matsuzawa MMT-X) Vickers hardness machine with 500gf for 10 seconds. Five readings were taken with standard distance of app 0.5mm from every indentation to attain reliability in results. Diamond indenter is used for accuracy of results. The highest measured value is 101.1HRC. This confirms increase in hardess value. Hardness value has been increased due to the addition of ZrSiO4 with metal matrix. During Composite fabrication reinforcement strengthens the metal matrix and the unique hardness property of ZrSiO 4 is transferred to the specimen. Table 2. The hardness test value. Measurement Position(mm)

Sl. No

Diagonal(Îźm)

Hardness

Conv.

Scale

Load

8.183

0.653

8.209

500

105.32

100.06

87.9

HRC

8.505

0.653

8.530

500

102.33

98.50

91.9

HRC

8.819

0.653

8.843

500

108.02

103.33

83.0

HRC

8.643

0.666

8.669

500

108.59

95.80

88.7

HRC

8.406

0.666

8.432

500

103.19

88.26

101.1

HRC

Maximum value

101.1

HRC

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Tensile test Three samples were made to have high reliability in results. The specimens were made as per ASTME8 standard. The tensile test was carried out using INSTRON tensile testing machine. The maximum Ultimate Tensile Strength value is 0.094Gpa. This elevated strength is acheived due to the addition of ZrSiO4 with metal matrix. As per the microstructure analysis cluster formation was observed. This can cause degradation of mechanical property. Prevention or reduction of clusters during casting would have achieved higher tensile property. Tensile test shows the kind of fracture what happened is brittle fracture and this is due to reinforcement particles in aluminum matrix. Table 3. The tensile strength of Composite. Weight % of reinforcements

Al6061/ ZrSiO4-10%

SL.NO

Maximum Load (N)

UTS (GPa)

Modulus (Automatic Young's)

Proof Stress (MPa)

(MPa)

2499.77112

0.062

29574.066

58.15

2925.52710

0.073

36092.384

66.94

3784.77573

0.094

38323.753

78.04

Maximum value

0.094

Fractography It has been observed that uniform distribution of reinforcement in the metal matrix phase is one of the challenges encountered in metal matrix composite during processing which highly influence its strength. There are many factors constitute this issue. Settling of reinforcement particles in the bottom of crucible during holding time causes uneven distribution. This can arise as a result of density differences between the reinforcement particles and the metal matrix. The stirring blade design, rpm of stirrer too influence reinforcement distribution. Fig 2(a) & 2(b) shows pullouts during tensile test, which causes fracture of specimen predominantly in composites. This is due to the level of affinity between Al 6061 alloy and ZrSiO4. Also grain size and shape of reinforcement particle determine bonding ability. If the reinforcement does not mix and bond with metal matrix, during tensile test due to the lack of bonding it fails. This has caused reduction of tensile strength in the above composite specimen.

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Fig. 2, (a) SEM image after tensile test.

Fig. 2, (b) SEM image after tensile test. Wear Analysis The type of wear testing set up used to carry out experiment is a pin-on-disc Ducom Linear Reciprocating Tribometer. Wear test was conducted at a load of 50N. The distance travelled by mild steel pin on the specimen was 720m. The temperature range was from 35C to 44C with a frequency of 10Hz. No lubricant was used as test is carried out in dry conditions. Care has been taken that the specimen under test was continuously cleaned with woolen cloth to avoid the entrapment of debris for accurate results. Table 4 shows the values obtained during wear test. The frictional force value is 32.189N and Coefficient of friction is directly proportional to frictional force and its value is of is 0.635. The values clearly prove the high wear resistant property of composite specimen. It is evident that wear resistance behaviour of composite increased due to the addition ZrSiO4 in the metal matrix.

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Table 4. Shows wear test results. COF

FF(N)

TEMP (°C)

LOAD (N)

SPEED

WEAR (μm)

0.635

32.189

34.622

50.704

608.964

104.206

Summary. Composite specimen was successfully designed and fabricated using stir casting bottom pouring technique. Microstructure analysis proves the existence and distribution of ZrSiO 4 in the metal matrix. Hardness test proves improvement of hardness value up to 40% due to the good cohesion between metal matrix and reinforcement phase. Tensile test result proves elevation in mechanical property and it is minimum level due to the agglomeration of reinforcement particles and poor boning. Optical micro graphs strengthen this fact. Wear resistant property which is one of the peculiar properties of Composite has been achieved due to reinforcement of ZrSiO4 in metal matrix Al 6061.The wear is measured in microns and its value is 104.206μm. Altogether above fabrication and tests concludes successful fabrication of aluminium metal matrix composite with elevated metallurgical mechanical and tribological property. References [1] Alaneme, K. K., & Bodunrin, M. O. (2013). Mechanical behaviour of alumina reinforced AA 6063 metal matrix composites developed by two step-stir casting process. Acta Technica Corviniensis-bulletin of engineering, 6(3), 105. [2] Sreenivasan, A., Paul Vizhian, S., Shivakumar, N. D., Muniraju, M., & Raguraman, M. (2011). A study of microstructure and wear behaviour of TiB2/Al metal matrix composites. Latin American Journal of Solids and Structures, 8(1), 1-8. [3] Skolianos, Stefanos. "Mechanical behavior of cast SiC p-reinforced Al-4.5% Cu-1.5% Mg alloy." Materials Science and Engineering: A 210.1 (1996): 76-82. [4] Singh, D., Singh, H., Kumar, S., & Singh, G. (2012). An Experimental investigation of Mechanical behavior of Aluminum by adding SiC and Alumina. International Journal on Emerging Technologies, 178-184. [5] Liang, Y. H., Wang, H. Y., Yang, Y. F., Wang, Y. Y., & Jiang, Q. C. (2008). Evolution process of the synthesis of TiC in the Cu–Ti–C system. Journal of Alloys and Compounds, 452(2), 298-303. [6] Min, S. O. N. G. (2009). Effects of volume fraction of SiC particles on mechanical properties of SiC/Al composites. Transactions of Nonferrous Metals Society of China, 19(6), 1400-1404. [7] Prabu, S. B., Karunamoorthy, L., Kathiresan, S., & Mohan, B. (2006). Influence of stirring speed and stirring time on distribution of particles in cast metal matrix composite. Journal of Materials Processing Technology, 171(2), 268-273. [8] Aruri, D., Adepu, K., Adepu, K., & Bazavada, K. (2013). Wear and mechanical properties of 6061-T6 aluminum alloy surface hybrid composites [(SiC+ Gr) and (SiC+ Al 2 O 3)] fabricated by friction stir processing. journal of materials research and technology, 2(4), 362-369. Cite the paper S. JohnyJames, A. Raja Annamalai (2017). Fabrication of Aluminium Metal Matrix Composite and Testing of Its Property. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.62.86.695

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Determination of Activation Energies from Complex Impedance Parameters of Microwave Sintered NiMgZn Ferrites 54 K. Chandra Babu Naidu1, W. Madhuri1,a 1 – Ceramic Composite Laboratory, Centre for Crystal Growth, SAS, VIT University, Vellore 632014, Tamilnadu, India a – madhuriw12@gmail.com DOI 10.2412/mmse.4.28.99 provided by Seo4U.link

Keywords: spinel ferrites, structure, impedance properties.

ABSTRACT. The Ni0.2Mg0.8-xZnxFe2O4 (x = 0.2, 0.4, 0.6 & 0.8) ferrites are prepared via microwave double sintering solid state reaction method. The phase purity and structure are confirmed by diffraction studies. These investigations reveal that the lattice parameter as well as crystallite sizes are increasing with zinc content. In addition, the variation of complex impedance (Z*) parameters as a function of temperature and frequency is studied. The activation energies of ferrites are evaluated from Arrhenius plots and observed to be decreasing with increase of x value.

Introduction. Spinel ferrites are used as well known electromagnetic materials such as due to their various electrical and magnetic properties [1-4]. Hiti [5] reported the variation of distinct ac-electrical properties with increase of zinc composition using conventional solid state reaction method. The microstructure and electrical properties of ferrites are analyzed by impedance (Z*) properties [6]. This approach offers discussion on real (Z') and imaginary parts (Z") of impedance providing the material properties. It also attributes the bulk and grain boundary effect from the relaxation behaviour of Z' and Z" parameters [6]. The complex impedance (Z*) is generally written as Z* = Z' – j Z". The real and imaginary parts are calculated using the equations: Z' = Z Cosφ and Z" = Z Sinφ, where φ denotes the phase [7]. In this study the authors discuss the behaviour of Z', Z" and relaxation time as a function of temperature and frequency. Also, the authors attempt to evaluate the activation energies from relaxation time. Experimental Procedure. A series of Ni0.2Mg0.8-x ZnxFe2O4 (x = 0.2, 0.4, 0.6, 0.8) are synthesized by microwave double sintering technique. The starting materials of NiO (99.5% purity, Sigma Aldrich), MgO (99.4% purity, Sigma Aldrich) and Fe2O3 (99.5% purity, Sigma Aldrich) are weighed according to the stoichiometric ratio and grinded (for 14hr) to make fine powder. The fine powder is pressed into cakes of 20 mm disk shape by applying 0.5 tons pressure in hydraulic press. The cakes are calcined at a temperature of 8000C for 30min. in microwave furnace (V.B. Ceramics, India). Later the calcined cakes are crushed into powder and are again grind for another 4hrs to make it into fine powder. The ferrite powder is uniaxially pressed into pellets (10mm diameter) applying 1 ton pressure. The pellets and powder samples are sintered at 10000C for 30min in microwave furnace fitted with two magnetrons of 2.45GHz frequency with a power output of 2.2kW. The sintered samples are characterized using X-ray diffractometer (Bruker X-Ray Powder Diffraction Meter, CuKα, λ=0.15418nm) at room temperature for structural identification. HIOKI 3532-50 LCR HiTESTER (Japan) is used for impedance analysis. Results and Discussions.

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Structural Properties. Fig.1 shows the diffraction pattern of Zn substituted NiMg ferrites. Phase purity and structure formation of spinel ferrites is confirmed. The peak positions are indexed in Fig.1 and are in consistent with standard JCPDS data file No. 08-0234. The crystallite size (D) is calculated using Debye-Scherrer formula [8, 9] and the corresponding values are changing between 22-50nm. The lattice constant â&#x20AC;&#x2DC;aâ&#x20AC;&#x2122; is increasing with increasing x value as the ionic radius of zinc (0.083 nm) is greater than that of magnesium (0.066 nm) and nickel (0.078 nm) [10]. X-ray density (Dx) is evaluated using relation [9]: đ?&#x2018;?đ?&#x2018;&#x20AC;

Dx = đ?&#x2018; đ?&#x2018;&#x17D;3

(1)

where Z is the no. of molecules per unit cell (Z = 8), M is the molecular weight of the composition, N is Avogadroâ&#x20AC;&#x2122;s number (6.023 x 1023) and a is the lattice parameter. The bulk density (Db) is estimated by Archimedes principle. Both the densities are increasing with x. Further, porosity (P %) is computed and found to be decreasing with increase of Zn2+ ions. The structural parameters are mentioned in Table.1.

Fig. 1. XRD of Ni0.2Mg0.8-x ZnxFe2O4 (x = 0.2-0.8). Impedance Analysis. The frequency dependence of real (Z') and imaginary (Z") parts at the selected temperatures (313K-773K) is depicted in Fig.2. It is seen from Fig.2 that Z' shows a constant trend at lower frequencies for x = 0.2 â&#x20AC;&#x201C; 0.8. The real part is combined for all selected temperatures at higher frequencies. The space-charge effect [11, 12] is responsible for achieving larger Z' values at lower frequencies. But Z' values are decreasing with increase of temperature which can be attributed to smaller density of trapped charges [11]. Similarly, the frequency dependence of Z" in the range of 313K-773K is shown in Fig.2. The relaxation peaks are moved to higher frequencies with increase of temperature from 313K-773K. It reveals that the NiMgZn ferrites show the temperature dependent MMSE Journal. Open Access www.mmse.xyz

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relaxation process. The Z" versus frequency (with temperature) plots (Fig.2) provides the relaxation frequency. Table 1. Structural and electrical parameters of NiMgZn ferrites. x

0.2

0.4

0.6

0.8

a (Å)

8.383

8.394

8.401

8.412

D (nm)

21.6

27.4

32.5

49.7

Dx(g/cm3)

4.850

5.015

5.186

5.350

Db(g/cm3)

4.525

4.739

4.955

5.183

Porosity (P %)

6.7

5.5

4.5

3.1

E1 (eV)

0.37

0.34

0.32

0.30

E2(eV)

0.32

0.25

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Fig. 2. Frequency dependence of Z' and Z" parameters at selected Kelvin temperatures. In addition, the relaxation time (τ) is calculated using the relation: τ = (2πf)-1 where f is the relaxation frequency. As the temperature goes on increasing the relaxation frequency also increased. Thus, the relaxation time is decreased with temperature. Similar trend is observed by Laurel et al [11]. Therefore, the variation of τ with T follows the Arrhenius law: τ = τ0 exp (-Ea/KbT), where τ0 is a preexponential factor, Kb is Boltzmann constant and T is absolute temperature [13]. The Arrhenius plots (lnτ versus 1/T plots) are drawn (Fig.3) to find the activation energies of ferrites. The plots reveal two linear slopes that belong to both extrinsic and intrinsic regions. These two slopes are taken at two regions i.e. region -I high temperature region (>700K) and region-II low temperature region (<700K). The slope change is usually occurred in ferrites due to either ferri – paramagnetic transitions or two hopping mechanism as reported in literature [14]. The estimated activation energies (E 1 & E2) are reported in Table.2. It is observed from results that the energies at high temperature region are more than that of low temperature region. The conduction process is of extrinsic type at low temperature region. This can be attributed to the presence of impurities. Similar slope changes at two regions are reported in the literature [15].

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Fig. 3. Arrhenius plots (lnτ Vs. 1/T plots) of NiMg ferrites from impedance relaxations. References [1] K. Chandra Babu Naidu and W. Madhuri, Effect of non-magnetic Zn2+ cations on initial permeability of microwave treated NiMg ferrites, International Journal of Applied Ceramic Technology 13 (2016) 1030-1035 [2] K. Chandra Babu Naidu and W. Madhuri, Microwave Processed NiMg Ferrites: Studies on Structural and Magnetic Properties, Journal of Magnetism and Magnetic Materials 420 (2016) 109116 [3] K. Chandra Babu Naidu, S. Roopas Kiran and W. Madhuri, Microwave Processed NiMgZn Ferrites for Electromagnetic Interference Shielding Applications, IEEE Transactions on Magnetics (2016), DOI: 10.1109/TMAG.2016.2625773 [4] H.M. Zaki, S.H. Al Heniti, T.A. Elmosalami, Structural, magnetic and dielectric studies of copper substituted nano-crystalline spinel magnesium zinc ferrite, Journal of Alloys and Compounds 633 (2015) 104–114 [5] M.El Hiti, Dielectric behavior and ac-conductivity of Zn-substituted Ni-Mg ferrites, Journal of Magnetism and Magnetic Materials 164 (1996) 187-196 [6] Md. T. Rahman and C. V. Ramana, Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite Ceramics, Journal of Applied Physics 116 (2014) 164108-10 [7] Laurel Simon Lobo, S. Kalainathan, A. Ruban Kumar, Investigation of electrical studies of spinel FeCo2O4 synthesized by sol-gel method, Superlattices and Microstructures 88 (2015) 116-126 [8] M.A. Amer, T. Meaz, S. Attalah, A.I. Ghoneim, Annealing effect on structural phase transition of as-synthesized Mg0.1Sr0.1Mn0.8 Fe2O4 nanoparticles, Journal of Alloys and Compounds 654 (2016) 4555 [9] K. Chandra Babu Naidu, T. Sofi Sarmash, V. Narasimha Reddy, M. Maddaiah, P. Sreenivasula Reddy and T. Subbarao, Structural, Dielectric and Electrical Properties of La 2O3 doped SrTiO3 Ceramics, Journal of The Australian Ceramic Society 51 (2015) 94 – 102

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[10] M.A.Amer, M.El Hiti, Mossabaur and X-ray studies for Ni0.2Mg0.8-xZnxFe2O4 ferrites, Journal of Magnetism and Magnetic Materials 234 (2001) 118-125 [11] Laurel Simon Lobo, A. Ruban Kumar, Investigation of structural and electrical properties of ZnMn2O4 synthesized by sol–gel method, Journal of Material Science: Materials Electronics DOI: 10.1007/s10854-016-4714-z [12] D. Kothandan and R. Jeevan Kumar, Investigations on Electrical and Thermal Properties of Rare Earth Doped BiZnSr Borate Glasses, Journal of The Australian Ceramic Society 52 (2016) 156 – 166 [13] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, P. Sreenivasula Reddy, D. Jhansi Rani and T. Subbarao, Synthesis and Characterization of MgO- doped SrTiO3 Ceramics, Journal of The Australian Ceramic Society 52 (2016) 95 – 101 [14] G.Aravind, Abdul Gaffoor, D. Ravinder, V. Nathania, Impact of transition metal ion doping on electrical properties of lithium ferrite nanomaterials prepared by auto combustion method, Advanced Material Letters 6 (2015) 179-185 [15] K. Chandra Babu Naidu and W. Madhuri, Microwave Assisted Solid State Reaction Method: Investigations on Electrical and Magnetic Properties NiMgZn Ferrites, Materials Chemistry and Physics 181 (2016) 432-443 Cite the paper K. Chandra Babu Naidu, W. Madhuri (2017). Determination of Activation Energies from Complex Impedance Parameters of Microwave Sintered NiMgZn Ferrites. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.4.28.99

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Structural and Dielectric Properties of CuO, PbO and Bi 2O3 Doped SrTiO3 Ceramics55 T. Sofi Sarmash1, V. Narasimha Reddy1,a, T. Vidya Sagar1, M. Maddaiah1, T. Subbarao1 1 – Materials Science Lab, Dept. of Physics, S K University, Ananthapuramu – 515 003, A. P, India a – venkateswararaoikp@gmail.com DOI 10.2412/mmse.78.43.129 provided by Seo4U.link

Keywords: dielectric properties, glass ceramics, X-ray diffract meter, Ceramic titanates.

ABSTRACT. Copper oxide, lead oxide and bismuth oxide each 10% doped separately with 90% SrTiO3 (ST) ceramic powders were processed by solid-state route technique. We reported the effect of Cu+2, Pb+2 and Bi+3 ions on the dielectric response of ST and copper addition established the substantial increase in dielectric constant (ε r) than undoped ST from 303K-673K and low loss (tanδ) for good dielectric applications. In case of lead doped ST the strong relaxation dynamics of loss factor was observed at higher temperatures and dielectric constant plots established the curie transition temperature Tc = 653K revealing the structural transformation from cubic to tetragonal phase. But bismuth doped ST contrary to the expectations exhibited the decreasing trend of permittivity form 303K-525K and afterwards showed increasing nature with relaxations. The microstructure was examined by field emission scanning electron microscope (FESEM). Some additional phases SrCu3Ti4O12, PbTi3O7, SrBi3Ti5O18 and TiO2 rutiles were detected by X-ray diffraction technique.

Introduction. Copper (II) oxide is a p-type semiconductor of band gap 1.2 eV used to produce dry cell batteries [1]. It can have applications as ceramic resistors, magnetic storage media, gas sensors, semiconductors and solar energy transformation. When transition metals are added up to the ST magnetic as well as ferroelectric properties can be induced. For instance in recent investigations Mn+2 ions could induce the electric and magnetic dipoles into the system. Likewise as in ref [2, 3] if Cu+2 ions occupy the Sr+2 site, dielectric and magnetic anomalies could be induced as the ionic radius of Sr+2 (0.144nm) is larger than Cu+2 (0.121nm). But on the other hand anti ferromagnetic spin ordering is being evolved, if Cu+2 ions occupy the Ti+4 sites. Even for the higher frequencies copper doped ST showed high dielectric constant. PbO is a toxic material and when doped to strontium titanate (ST) is found experimentally to be a glass ceramic material [4]. Glass ceramics have been commercially used at wide range and limited work has been done over the borosilicate glass ceramic system, in spite of its wide range of applications. The ferroelectric PST thin films have been termed as the candidate materials for the applications in various tunable microwave devices and in high density dynamic random access memories. On the other hand ferroelectric thin films have got much attention in manufacturing various functional devices for optical applications. No detailed report is available in the literature about the dielectric properties of PST ceramics. Both of the materials promote liquid phase sintering at low concentrations about 1-2 % only. Recently in case of bismuth oxide doped ST a novel microstructure was observed which is useful in understanding the grain boundary barrier layer capacitors (GBBLC) and efficient ferro-electric relaxations have been observed for the industrial applications when Bi2O3 doped with Ba0.8Sr0.2TiO3 ceramics [5].Yu Zhi et al [6] reported the low temperature and high temperature dielectric properties. In the recent literature Naidu et al. [2-4, 7, 8], Kumar et al. [9] and Maddaiah et al. [2, 10] investigated the effect of various elements (La, Mg, Mn, Cu, Zn & Bi) on electrical properties such as dielectric constant, loss, thermoelectric power, acconductivity and dc-conductivity of SrTiO3 electro ceramic material. In this study the author is © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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intended to make a novel comparative study of the structural, micro structural and dielectric properties of CuO, PbO and Bi2 O3 doped ST Ceramics to decrease the sintering temperature of strontium titanate which have not been discussed in earlier literature. Experimental Procedure The ceramic samples of CuO, PbO and Bi2O3 10% each doped individually with 90% SrTiO3 were prepared by solid state diffusion method. At the outset ST powders have been synthesized using the raw materials of SrCO3 (99.9% purity) and TiO2 (99.9% purity). The mixed powders were calcined at temperature 14000C for 13hrs and the shrinkage of compound was apparently identified. Latter ST was mixed separately with CuO, PbO and Bi2 O3 and ball milled for nearly 12 hrs. After wards these samples were calcined at 10500C, 9500C and 11000C respectively each for 13hrs and the pellets of thickness 0.14cm and radius of 0.62cm have been prepared. The powders and the pellets sintered at 11000C, 10000C and 12000C respectively for 4hrs were characterized using XRD (BRUKER X-Ray Powder Diffract Meter, CuKÎą) at room temperature and HIOKI 3532-50 LCR HiTESTER (Japan) for structural, surface morphological analysis and dielectric properties respectively. LCR controller over the temperature range from RT to 6000C operated at the frequencies from 42 Hz-5MHz having the heating rate of 0.50C/min used for dielectric properties. Results and Discussions In fig.1, we reported the comparison XRD spectra of pure and doped ST. Diffraction maxima were observed in the diffraction spectra which are corresponding to the cubic perovskite lattice of ST. The effect of copper ions on the lattice parameter of undoped ST was clearly observed in ref [2] at low concentrations i.e. at low concentration of copper addition to pure ST decreases the lattice parameter (a). Similar reports were achieved in the present investigation. The lattice parameter of pure ST was reported in ref [2] and in case of CuO (10%) doped ST (90%) â&#x20AC;&#x2DC;aâ&#x20AC;&#x2122; value was slightly decreased to 0.3893nm. Since the ionic radius of Cu+2 (0.121nm) is smaller than that of Sr+2 (0.144nm) [2]. Along with single perovskite phases some non-perovskite second phases have been detected that correspond to TiO2 rutiles and SrCu3Ti4O12 phases specified in fig.1. Furthermore the average crystalline size (DP=114.9nm) using Scherer formula and average dislocation density (Ď =8.03x1013(m-2) were established according to the following equations [11-14]. đ?&#x2018;&#x2DC;đ?&#x153;&#x2020;

Dp = đ?&#x203A;˝ đ??śđ?&#x2018;&#x153;đ?&#x2018; đ?&#x153;&#x192; Ď =đ??ˇâ&#x2C6;&#x2019;2 where k is a constant and is equal to 0.9, Î¸ is diffraction angle, Îť=0.154056 nm (CuKÎą) and Î˛ is full width half maxima. In the XRD pattern of undoped ST and PbO doped ST (referred as PST in fig.1), it can be seen that the two compounds exhibit cubic crystalline structure having single perovskite reflection peaks with the exception of few additional phases corresponding to the presence of PbTi3O7 (PT) and TiO2 (R) phases [15]. The huge enhancement in the intensity of diffraction lines depends on structure factor (F). At 2-theta angle 32.490 the maximum counts 9730 and similar miller indices (h k l) were noticed as (100), (110), (111), (200), (210), (211), (220) and (310) that of undoped ST. However, the lattice parameters were achieved as a=b=c=3.8930A0 and Îą= Î˛= Îł=900 and are in good consistent with literature data. Hence it is confirmed that the structure of present compound is cubic. Depends on obtained lattice parameters the practical value of unit cell volume (59.02x10 -24cm3) was calculated which is comparable to the unit cell volume of undoped ST as reported in JCPDC file 35-734. Furthermore the average crystalline size (DP=117.2nm). In XRD pattern of bismuth doped ST all peaks are in consistent with the cubic primary phases and Sr2Bi4Ti5O18 was detected as a secondary peak. The lattice constant was found as a=b=c=0.3895 nm.

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Table 1. Shows the XRD profile data of CuO doped SrTiO3 ceramics. 2θ

d-space (A0) CuST PbST BiST

ρx10-13(m-2)

Dp(nm) CuST PbST BiST

22.842 3.8930 3.8930 3.8831 110.1

106.5

8.25

30.89

8.82

32.492 2.7550 2.7550 2.7178 131.8 112.5 117.5

5.76

7.9

8.81

40.049 2.2506 2.2506 2.2485 129.8 130.7 114.3

5.94

5.85

7.63

46.56 1.9498 1.9498 1.9482 123.1 110.8 106.0

6.59

8.15

8.9

52.439 1.7441 1.7441 1.7435

86.9

56.9

CuST PbST BiST

34.4

70.7

13.24

84.5

20.01

57.865 1.5928 1.5928 1.5918 112.6 108.8

97.3

7.89

8.45

10.56

67.908 1.3795 1.3795 1.3792 113.3 108.1

87.6

7.79

8.4

13.03

79.0

8.85

12.8

16.02

77.26 1.2342 1.2342 1.2339 106.3

88.4

Fig. 1. XRD Spectrum of pure, CuO, PbO and Bi2O3 doped SrTiO3 ceramics.

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Fig. 2. FESEM micrographs of CuO, PbO and Bi2O3 doped SrTiO3 ceramics.

Fig. 3. Dielectric constant Vs temperature plots of (a) CuO, (b) PbO and (c) Bi 2O3 doped SrTiO3 ceramics. In case of copper doped ST permittivity and loss were decreasing with increase of frequency. These trends were approximately identical incase of undoped ST. At RT sample showed εr value of 802 which is almost four times the εr value of pure ST and low loss of 0.0046 at RT. In case of lead doped ST initially the permittivity (εr) is increasing gradually with increase of temperature up to Tc and later showing decreasing trend. Obviously, cubic to tetragonal structural transformation at the Curietemperature of Tc= 653K has been observed. This explicitly established a fact that addition of lead MMSE Journal. Open Access www.mmse.xyz

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oxide diminishes the Curie temperature of pure ST. Moreover, the lead addition cannot induce permittivity of pure ST at room temperature. The loss factors (tanδ) were noted as 0.00815 and 0.24837 at 0.1 kHz and 5 MHz respectively (at RT). But for the similar frequencies at 693K tanδ values were obtained sequentially as 1.9544 and 0.07543. Apparently, bismuth doped ST was unable to induce permittivity but showed loss of 0.00935 at RT. Due to the high dielectric constant and low loss established at RT, copper doped ST has got recognition as a candidate material for the applications in electronic devices such as phase shifters, oscillators, micro wave tunable circuits, resonators and charge stored capacitors [16-18].

Fig. 4. Dielectric loss Vs temperature plots of (a) CuO, (b) PbO and (c) Bi2O3 doped SrTiO3 ceramics. Summary. In conclusion of this work (i) some additional phases SrCu 3Ti4O12, PbTi3O7, SrBi3Ti5O18 and TiO2 rutiles were detected (ii) in this study low loss was obtained for all ST based dopants for device applications. Especially, copper doped ST induced the permittivity of pure ST. References [1] "Cupric Oxide Data Sheet". Hummel Croton Inc. 2006-04-21. Retrieved 2007-02-01. [2] M. Maddaiah, K. Chandra Babu Naidu, D. Jhansi Rani, T. Subbarao, Synthesis And Characterization of CuO-Doped SrTiO3 Ceramics, Journal of Ovonic Research 11 (2015) 99-106 [3] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, V. Narasimha Reddy and T.Subbarao, Structural and dielectric properties of CuO-doped SrTiO3 ceramics, AIP Conference Proceedings 1665 (2015) 040001 [4] K. C. Babu Naidu, T.S. Sarmash, M. Maddaiah, A. Gurusampath Kumar, D. Jhansi Rani, V. Sharon Samyuktha, L. Obulapathi, T.Subbarao, Structural and Electrical Properties of PbO-Doped SrTiO3 Ceramics, Journal of Ovonic Research 11 (2015) 79-84 [5] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, P. Sreenivasula Reddy, D. Jhansi Rani and T. Subbarao, Synthesis and Characterization of MgO- doped SrTiO3 Ceramics, Journal of The Australian Ceramic Society Volume 52 (2016) 95 – 101 MMSE Journal. Open Access www.mmse.xyz

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[6] K. Chandra Babu Naidu, T. Sofi Sarmash, V. Narasimha Reddy, M. Maddaiah, P. Sreenivasula Reddy and T. Subbarao, Structural, Dielectric and Electrical Properties of La2O3 Doped SrTiO3 Ceramics, Journal of The Australian Ceramic Society 51 (2015) 94 – 102 [7] S. Anil Kumar and K.Chandra Babu Naidu, Structural and Dielectric Properties of Bi2O3 Doped SrTiO3 Ceramics, International Journal of ChemTech Research 9 (2016) 58-63 [8] M. Maddaiah, A. Guru Sampath Kumar, L. Obulapathi, T. Sofi Sarmash, K. Chandra Babu Naidu, D. Jhansi Rani, T. Subba Rao, Synthesis and Characterization of Strontium Doped Zinc Manganese Titanate Ceramics, Digest Journal of Nano materials and Biostructures 10 (2015) 155-159 [9] K. Chandra Babu Naidu and W. Madhuri, Effect of Nonmagnetic Zn2+ Cations on Initial Permeability of Microwave-treated NiMg Ferrites, International Journal of Applied Ceramic Technology, 1–6 (2016), DOI:10.1111/ijac.12571 [10] K. Chandra Babu Naidu, W. Madhuri, Microwave processed NiMg ferrite: Studies on structural and magnetic properties, Journal of Magnetism and Magnetic Materials 420 (2016) 109–116 [11] D Jhansi Rani, A Guru Sampath Kumar, T Sofi Sarmash, K Chandra Babu Naidu, M Maddaiah, T Subba Rao, Effect of Argon/Oxygen Flow Rate on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films, Journal of the Minerals, Metals and Materials Society 68 (2016) 1647-1652 [12] V. Narasimha Reddy, K. Chandra Babu Naidu, T. Subba Rao, Structural, Optical and Ferroelectric Properties of BaTiO3 Ceramics, Journal of Ovonic Research 12 (2016) 185- 191 [13] Chandra Babu Naidu K., Madhuri W, Microwave assisted solid state reaction method: Investigations on electrical and magnetic properties NiMgZn ferrites, Materials Chemistry and Physics 181 (2016) 432-443 [14] M. Vasubabu, C.Suresh babu, R.Jeevan Kumar, Studies on dielectric behaviour of Myrtaceace and Mimosoideae family Indian wood species, International Journal of ChemTech Research Vol.9, No.02, 2016, pp 80-84 [15] D Kothandan, R. Jeevan Kumar, Investigations on Electrical and Thermal Properties of Rare Earth Doped BiZnSr Borate Glasses, Journal of The Australian Ceramic Society 52 (1) (2016) 156166. [16] A. Kiruthiga and T.Krishnakumar, Synthesis and Characterization of Microwave-assisted ZnO Nanostructures, International Journal of ChemTech Research Vol.8, No.7, 2015, pp 104-110 [17] Ping-an Fanga, Hui Gua, Hui Shena, Yuan-wei Songa, Ping-chu Wanga, Miran Cˇ ehb A novel interfacial microstructure in SrTiO3 ceramics with Bi2O3-doping Journal of the European Ceramic Society 24 (2004) 2509–2513 [18] Fathi Bahri, Hamadi Khemakhem, Dielectric propertiesofBi-dopedBa0.8Sr0.2TiO3 ceramic solid solutions Ceramics International 39 (2013) 7571–7575 Cite the paper T. Sofi Sarmash, V. Narasimha Reddy, T. Vidya Sagar, M. Maddaiah, T. Subbarao (2017). Structural and Dielectric Properties of CuO, PbO and Bi2O3 Doped SrTiO3 Ceramics. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.78.43.129

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Multiwalled Carbon Nanotubes (MWCNT) / Poly O-Cresophthalein Complexone Film (POCF) Modified Electrode for Determination of Cd (ll) Using Anodic Stripping Voltammetry 56 J. Jayadevimanoranjitham1, C. Lakshmi Devi1, S. Sriman Narayanan1,a 1 – Department of Analytical Chemistry, School of Chemical sciences, University of Madras, Guindy Campus, Chennai– 600 025, Tamil Nadu, India a – sriman55@gmail.com DOI 10.2412/mmse.97.37.377 provided by Seo4U.link

Keywords: multiwalled carbon nanotube, cadmium, POCF, stripping voltammetry.

ABSTRACT. This work describes about the anodic stripping voltammetric determination of trace amount of cadmium ions using Multiwalled Carbon Nanotube / Poly O-Cresophthalein Complexone Film (MWCNT/POCF) modified electrode. The proposed modified electrode was prepared by electropolymerization of O-Cresophthalein Complexone over the MWCNT on Paraffin Impregnated Graphite Electrode (PIGE).The surface morphology of MWCNT/POCF modified electrode was characterized by Scanning Electron Microscope (SEM) and Square Wave Voltammetry (SWV). A linear range of 18µg/L to 332µg/L with a detection limit of 6.2µg/L was obtained for the determination of Cd (ll) using MWCNT/POCF modified electrode. The modified electrode was found to be environment friendly mercury free electrode for sensitive of determination of Cd (ll).

Introduction. Heavy metals are highly toxic environmental pollutant which causes major effects to the human health even at lower concentration. Even though some of heavy metals used for various biological functions in human beings but they became toxic when they exceed certain threshold limits. Cadmium is one of the toxic heavy metal that enters the water bodies and is a major pollutant through various industrial and agricultural sectors [1]. Cadmium mainly targets the kidney but causes some health effects to other organs such as lung, liver. Cadmium stored in the kidney for longer period, mainly affects the proximal tubular cells of kidney which results in renal dysfunction. Due to prolonged exposure of air born cadmium human beings are affected by lung cancer [2]. Bones are degenerated to cadmium intake. So it is very important to develop simple and highly sensitive analytical methods for assessing environmental pollutants in soil, water, and air to improve the quality of environment and human life. Numbers of analytical techniques have been used to quantify the amount of Cd (ll). Anodic stripping voltammetry using modified electrode is a prominent analytical tool for determination of heavy metal ions because when comparing with other analytical techniques stripping voltammetry posses some of advantages such as insuit monitoring, less time consuming for sample preparation, high sensitivity and excellent reproducibility [3-5]. Basically electrochemical sensing of heavy metal ion using stripping voltammetry involves the usage of hanging mercury drop electrode [HMDE] and mercury film electrode [MFE] as working electrode, but due to the toxicity of mercury and difficulty in disposal of mercury electrodes, alternative methods without using mercury electrode have been developed using number of modifiers [6-8]. Here in we have developed mercury free electrode for the determination of Cd (ll) using multiwalled carbon nanotube and O-Cresophthalein Complexone as working electrode. Carbon nanotubes (CNTs) are recently used in stripping analysis because they have strong sorption properties, high mechanical © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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strength, high conductivity and high surface area [9]. O-Cresophthalein Complexone is a metal ion indicator and used for determination of metal ions [10]. Due to wide application of CNTs and metal chelating nature of O-Cresophthalein Complexone an attempt has been made to develop MWCNT/POCF modified electrode for the determination of Cd (ll). Experiment. The modified electrode was prepared by mechanically immobilizing MWCNT over the polished end of PIGE followed by electropolymerization of O-Cresophthalein Complexone over the surface of PIGE/ MWCNT electrode by dipping this electrode in 0.1M PBS pH 6 solution containing 0.1mM O-Cresophthalein Complexone dissolved in 0.1M NaOH. The resulted PIGE/ MWCT-POCF electrode was used for determination of Cd (ll). The determination of Cd (ll) involves preconcentration of metal ions towards the electrode surface by dipping the PIGE/ MWCT-POCF electrode in 0.1M ABS (pH 5) solution containing Cd (ll) and then solution was stirred which has resulted in the complex formation of Cd (ll) with POCF via four â&#x20AC;&#x201C;COO- group. Then this electrode was transferred to the fresh electrolyte 0.1M ABS (pH 5) solution to reduce the all the Cd (ll) to Cd (0) by applying a potential of -1.2V for 180s. The reduced metal ions were stripped by anodic stripping voltammetry using SQW from -1.2V to -0.3V in 0.1M ABS (pH 5). By measuring the peak current the quantity of Cd (ll) was measured. Regeneration of electrode is achieved by dipping the electrode in 0.1M EDTA (pH 5) solution for 120 sec. Fig.1 shows the scheme for preparation of modified electrode and determination of Cd (ll).

Fig. 1. Scheme for preparation of modified electrode and determination of Cd (ll). Results and discussion. The surface morphology of the modified electrode is characterized by SEM. Fig.2. Shows the SEM images of a) bare electrode b) MWCNT-POCF electrode c) MWCNT-POCF-Cd electrode d) EDX for MWCNT-POCF-Cd electrode. The SEM image of MWCNT-POCF shows the tube like structure for the presence of MWCNT and the polymer film is formed over the MWCNT. The white spherical shape in the Fig.2c show the presence of cadmium ions over the polymer film and the corresponding EDX spectrum confirms the presence of various elements in the electrode surface.

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Fig. 2. SEM image of a) bare electrode, b) MWCNT-POCF electrode, c) MWCNT-POCF-Cd electrode, d) EDX for MWCNT-POCF-Cd electrode. Determination of Cd (ll) by anodic stripping voltammetry. Under optimized condition the modified electrode was used for determination of Cd (ll) using square wave voltammetry. Fig.3 shows the SQW response of MWCNT-POCF modified electrode for Cd (ll) over the concentration range from 18µg/L to 332µg/L in 50 ml of 0.1M ABS pH 5 at the deposition time of 180s. From the figure we can see the linear increase in the peak current upon increasing the concentration of Cd (ll) with sensitivity of 0.0820µA/µg and a correlation coefficient of 0.9940 with a detection limit of 6.2µg/L.

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Fig. 3. a) Square wave voltammograms of different concentration of Cd (ll) in 0.1M ABS (pH 5), reduction potential of -1.2V, deposition time 180s., b) Corresponding calibration plot. Summary. A mercury free metal ion sensor using MWCNT-POCF modified electrode was successfully fabricated and used for determination of Cd (ll) in aqueous solution. The electrode was prepared by electropolymerization method. Since the POCF has more number of negatively charged ions, the metal ions easily forms complex.Then the metal ions were reduced by applying potential of -1.2V for 180s, this reduced metal was stripped to metal ions using anodic stripping voltammetry. On varying the concentration of metal ion the peak current is also increased linearly with the detection limit of 6.2µg/L. Hence the proposed modified electrode successfully used for determination of Cd (ll). Acknowledgements. The authors gratefully acknowledge university grants commission New Delhi, India for financial assistance through Rajiv Gandhi National Fellowship. References [1] Jarup L, Akesson A Current status of cadmium as an environmental health problem, Toxicol Appl Pharmacol. 2009, Aug 1, 238(3):201-8. DOI: 10.1016/j.taap.2009.04.020 [2] Contaminants in the Food Chain on a request from the European, Commission on cadmium in food. The EFSA Journal (2009) 980, 1-139. DOI:10.2903/j.efsa.2012 [3] Sukeri Anandhakumar, Jayaraman Mathiyarasu and Kanala Lakshimi Narasimha Phani, Anodic stripping voltammetric determination of cadmium using a “mercury free” indium film electrode Analyst, 2013, 138, 5674.DOI: 10.1039/c3an01070h [4] Saiwei Wu, Xiaolei Huang, Yuhua Wu, Liping Luo, Yuancheng Jin, Qun Li, Differential Pulse Anodic Stripping Voltammetry Detection of Cadmium with Nafion-Graphene Modified Bismuth Film Electrode Int. J. Electrochem. Sci., 10 (2015) 8255 – 8262. [5] Bang Lin Li, Zhi Ling Wu, Chang Hong Xiong, Hong Qun Luo, Nian Bing Li, Anodic stripping voltammetric measurement of trace cadmium at tin-coated carbon paste electrode, Talanta 88 (2012) 707– 710, Doi:10.1016/j.talanta.2011.11.070 [6] Deepak Singh Rajawa, Nitin Kumar and Soami Piara Satsangee Trace determination of cadmium in water using anodic stripping voltammetry at a carbon paste electrode modified with coconut shell powder, Journal of Analytical Science and Technology 2014, 5:19, DOI: 10.1186/s40543-014-00190. MMSE Journal. Open Access www.mmse.xyz

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[7] Bagheri H, Afkhami A, Shirzadmehr A, Khoshsafar H, Ghaedi H (2012) Novel potentiometric sensor for the determination of Cd2+ based on a new nano-composite. Int J Environ Anal Chem, DOI: 10.1080/03067 319.2011.6497 41 [8] Gil Ho Hwanga, Won Kyu Hana, Joon Shik Park b, Sung Goon Kanga, Determination of trace metals by anodic stripping voltammetry using a bismuth-modified carbon nanotube electrode, Talanta 76 (2008) 301â&#x20AC;&#x201C;308, DOI:10.1016/j.talanta.2008.02.039 [9] Tsai Y.C, Chen J.M, Li S.C, Marken F, Simple Cast-Deposited Multi-Walled Carbon Nanotube/NafionTM Thin Film Electrodes for Electrochemical Stripping Analysis Electrochem. Commun. 6 (2004) 917. DOI:10.1007/s00604-005-0364-1 [10] Brett Paull, Paul R. Haddad, Chelation ion chromatography of trace metal ions using metallochromic ligands, Trends in analytical chemistry, vol. 18, no. 2, 1999, DOI :10.1016/S01659936(98)00104-6 Cite the paper J. Jayadevimanoranjitham, C. Lakshmi Devi, S. Sriman Narayanan (2017). Multiwalled Carbon Nanotubes (MWCNT) / Poly O-Cresophthalein Complexone Film (POCF) Modified Electrode for Determination of Cd (ll) Using Anodic Stripping Voltammetry. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.97.37.377

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Spectroscopic Analysis of Gas Phase Astrophysical Molecule: Beryllium Monofluride57 R. Sindhan1, 3, P. Sriramachandran2, a, R. Shanmugavel2, S. Ramaswamy1, b 1 – Research Centre & PG Department of Physics, NMSSVN College, Madurai 625 019, Tamilnadu, India 2 – Physics Research Centre, VHNSN College, Virudhunagar 626 001, Tamilnadu, India 3 – Madurai Kamaraj University Constituent College, Thirumangalam 625 706, Tamilnadu, India a – srpsresearch2016@gmail.com b – sri_ramnivash@rediffmail.com DOI 10.2412/mmse.60.92.355 provided by Seo4U.link

Keywords: BeF, electronic transition moment, life time, vibrational temperature, Umbra.

ABSTRACT. The beryllium monofluride (BeF) is astrophysically significant molecule.The radiative transition parameters such as Franck-Condon (FC) factor, r-centroids, electronic transition moment, Einstein coefficient, band oscillator strength, radiative life time and effective vibrational temperature have been computed for A2 r  X 2 system of BeF molecule by the more reliable numerical integration procedure for the experimentally known vibrational levels using Rydberg-Klein-Rees (RKR) potential energy curves. The effective vibrational temperature of this system of BeF molecule was found to be nearly 5630 K. Hence, the radiative transition parameters as well as effective vibrational temperature help us to ascertain the presence of BeF molecule in the interstellar medium, S-stars and sunspots.

Introduction. Fluoride based beryllium are significant molecules in the field of astrophysics, astrochemistry and space science. The intensity distribution of the molecular band system of electronic states is controlled by the Franck-Condon (FC) factor. Franck-Condon (FC) factor are essential parameter for every molecular band system, this factor are used to calculation of the relative band intensities. The knowledge of r-centroids is useful in the discussion of the variation of the electronic transition moment with the internuclear separation and the band strengths. The evaluation of accurate FC factor and r-centroids of diatomic molecule is necessary for understanding the physical-chemical condition of the astrophysical and allied emitting source. Accurate values of FC factor [qv ' v " ] and r-centroids [r v ' v " ] provides direct information about radiative transition parameters (like electronic transition moment [R e (r v ' v" )] , band strength [Pv ' v " ] , oscillator strength [f v ' v" ] , Einstein coefficient [Av ' v" ] and radiative life time [ v ' ] ) and effective vibrational temperature of A2 r  X 2 band system of BeF molecule. Zun leu zhu et al. [1] have investigated A2 r  X 2

and B2  X 2 band systems of BeF molecule and its results are reported (such as spectroscopic parameters and molecular constant) by using the complete active space self-consistent-field method. The A2 r  X 2 system of BeF molecule some FC factor values[2], Einstein coefficient and radiative life time are available [3] by multireference single and double excitations configuration interaction approach. Jenkins [4] have experimentally investigated the rotational lines (R and Q) of the BeF bands are lie in the region 3140.8 Å to 2908.9 Å and these bands wavelength are λ00=3013.011 Å, λ01=3130.369 Å and λ10=2911.700 Å respectively. The dissociation energy is the © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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important parameter and this is confirm that the transition duration time of molecular band system. The experimental dissociation energy value is different to each other. And the values are 5.85 eV [5] and 6.26 eV [6]. Herzberg noted the dissociation energy is 5.4 eV [7] and 6.26 eV [8]. Previously, a number of lighter and heavier diatomic molecule [such as BeH, BeD, BeT [11], SrF [12]] have been detected in stellar spectra, Earth atmosphere, planets, interstellar source and sunspots Present investigations, the reliable values of FC factor and r-centroids for this band system of molecule have been evaluated by a numerical integration method and using molecular constants referred from literature [1] with RKR potential. These factors help us to compute the radiative transition parameters (like electronic transition moment, band strength, and radiative life time) and there by evaluated the effective vibrational temperature of the source [10]. The vibrational temperature and radiative transition parameters are help us to possible to presence of BeF molecules in the different layer of umbra and interstellar medium. Computation method. The intensity distribution of molecular band spectrum is proportional to the product of population, band strength and wavelength of molecular band for v ' v " electronic transition.

I v ' v" Nv 'v'4v" Pv ' v"

(1)

The FC factor is proportional to the electronic transition probability and it’s used to predict the intensity distribution of the molecular band and proper understand the physical and chemical condition of molecular band. The FC factor is defined as,

qv ' v"   v '  v"

(2)

where,  v ' and  v " are the eigen functions of respective upper (v’) and lower (v”) electronic states. The r-centroids are defined as internuclear separation between the v ' v " band and this value is unique. Thus,

r v ' v "

 v ' r  v"

(3)

 v '  v"

The potential energy curve is important to understand the intensity distribution of molecular band system. The potential energy curves of electronic states are constructed by using RKR potential at interval of 0.01 Å for the internuclear range 1.173 Å to 1.704 Å. The FC factors are computed by Bate’s [9] method of numerical integration according to detailed procedure provided [10]. The electronic transition moment of molecular band system is proportional to the population, photon energy, and intensity, FC factor. Thus,

 

Re r v ' v "

1/2

 I 4   N  v 'v" v 'v"   qv ' v "  1 v'

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(4)

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The oscillator strength is a dimensionless quantity and this is suggested the transition should be strong or weak. Thus, 2

fv ' v"  1.50 Av ' v" v ' v"

(5)

The radiative life time is an important quantity and this factor confirm that the formation of diatomic molecule. The life time is indirectly estimated with the help of Einstein coefficient. Thus,  1    Av ' v " 

 v'    v"

(6)



Therefore the effective vibrational temperature, graphical plot of log ( I4 ) v 'v" 

S v"



v 'v" 



verses

2 2  G (v' ) for A  r  X  band system of BeF molecule, where, G(v’) is vibrational quanta. The

least square fit method are used to obtained the straight line and its slope is equal to 0.625Bv / Tv . Results and discussion. The A2 r  X 2 system of BeF molecule, the difference in the internuclear separation is 0.025 Å. The Δv=0 sequence bands are most intense compared with Δv=±1 sequence and intensity are decreasing gradually band by band. The FC factor indicate that the (0,0) band is most intense band at 3088.82 Å. The region of this transition lies in the range of 2962 Å to 3203 Å. The r-centroids depend on the internuclear distance between the electronic states of the system. The variation of r-centroids versus wavelength is expected to be degraded towards red region and the variation should be linear. The r00 is slightly greater then (re'  re" ) / 2 , in this factor indicating that the potential energy curves for this band system are not fully anharmonic. The electronic transition moment with function of r-centroids has been evaluated and this is represented by Re r v ' v"  const.(1  0.787r v ' v" ) in the range of 1.212 Å< r v ' v " ”<1.625 Å. The electronic transition





moment slowly decreases with also decrease in r-centroids. The accurate value of FC factor and electronic transition moment help us well estimate the Einstein coefficient. The maximum value of oscillator strength are f 00  5.571 . For A2Πr state, the radiative life time for v’=0 of 24.04 ns and this state are slowly decreasing in v’=1,2,3 and after increasing up to v’=5. The estimated life time are compared with experimental values [3] and the values are tabulated in Table 1. The effective vibrational temperature of 5630 K for A2 r  X 2 system of BeF molecule was obtained the assumption of electronic transition moment as a function of r-centroids [10]. The effective rotational temperature value for A-X (1,1), (2,2) band system of beryllium monohydride is to be 4228 K, 4057 K and A-X (1,1) band system of BeD is to be 3941 K and A-X (2,2) of BeT to be 3243 K [11]. The rotational temperature value of BeH molecule is agree with the effective vibrational temperature of BeF molecule. Further, the effective rotational temperature of BeH, BeD and BeT molecular band system suggest that they are confirmed to be present in sunspot atmosphere of various heights of the cool regions. Hence, the radiative transition parameters as well as effective vibrational temperature help us to ascertain the presence of BeF molecule in the interstellar medium, S-stars and sunspots.

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Fig. 2. Graph showing the straight line is obtained by plotting of

  log   (Iλ 4 )v'v"  S v'v"  v"  v"

versus G(v' ) for

the A2 r  X 2 band system of BeF molecule. Table 1. Radiative transition parameter for A2 r  X 2 system of BeF molecules. Av 'v" v' , v"

0,0

v 'v" (Å)

I v 'v"

3088.82

93.50

qv 'v"

0.935 [0.882]

0,1

3203.27

6.50

rv 'v"

Re (rv 'v" )

(Å)

(a.u)

1.391

0.778

Pv 'v"

0.566

S v 'v"

1.000

0.065

2976.84

6.30

1.579

0.063

0.816

0.043

0.076

3082.99

81.10

1.212

0.811

1,2

3195.20

12.40

0.742

0.035

0.061

2,1

2973.03

11.50

0.494

0.873

0.818

0.083

0.147

0.115

3077.24

69.90

0.744

0.064

0.113

3187.24

17.80

1.417

0.178

3,2

2969.29

15.70

0.783

0.429

0.758

3,3

3071.58

59.70

0.597

2.667

24.04 [15.74]b

0.354

34.167

4.871

5.156

0.790

23.82 [15.93]b

4.913

0.651

29.826

0.120

0.212

7.497 [11.29]

1.233

[0.282]

0.820

0.157

0.410

4.237

[38.07]b 1.602

[0.246]

2.666

[11.52]b

[0.486]a 2,3

5.571

[8.1] 1.222

0.699

38.927

[0.208]a 2,2

(ns)

[47.78] 1.591

[0.192]

0.781

0.124

(x 10-2)

[6.6]b 1.403

[0.667]

 v'

[4.37]b

[0.113]a 1,1

f v 'v"

[59.03]

[0.109]a 1,0

(x 106 s1 )

0.747

0.088

0.155

6.773 [15.23]

1.431

0.786

0.369

0.652

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1.142 b

[16.12]b 0.896

25.799

23.68

3.651

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[0.339]a 3,4

3179.39

22.60

0.226

[29.03]b 1.614

0.823

0.153

0.270

[0.277]a 4,3

2965.62

19.00

0.190

9.645

1.462

[13.91]b 1.244

0.749

0.107

0.188

8.275

1.445

0.789

0.315

0.557

22.143

23.69 [16.45]b

1.092

[0.337]a 4,4

3065.99

50.60

0.506 [0.224]

4,5

3171.64

26.90

0.269

2962.01

21.50

[20.91] 1.625

[0.289] 5,4

0.825

0.183

0.323

0.215

1.256

0.751

0.121

0.214

[0.375]a 5,5

3060.49

4.20

0.420

11.627 [15.79]

3.122

1.754

9.459

23.78 [16.78]b

1.245

[20.51]b 1.461

0.792

0.264

0.466

[0.136]a

18.629 [14.72]b

2.617

35.60 [16.98]b

Note: aPelegrini et al [2]; bOrnellas et al. [3] v' , v" – transition band; v 'v" – wavelength (Å); I v 'v" – band intensity; qv 'v" – FC factor; rv 'v" –centroids;

Re (rv 'v" ) – electronic transition moment (a.u); Pv 'v" – band strength; S v 'v" – relative band strength;

Av 'v" – spontaneous emission rate (s-1); f v 'v" – absorption band oscillator strength;  v ' – radiative

lifetime (ns). Summary. The present work computes the radiative transition parameters of A2 r  X 2 band system, the FC factor and r-centroids which are mainly influence of intensity of vibrational band. The intensity of (0,0) band are found to be higher than diagonal array. The intensity of the band reflects the abundance of the molecule. Using intensity and wavelength of the bands, effective vibrational temperature is evaluated. The effective vibrational temperature of this band system is 5630 K. The f00  5.571 values confirmed that the transition should be strong. For A2Πr state, the radiative life time of v’=0 is 24.04 ns. Hence, the effective vibrational temperature and radiative life time help us to confirmed that the possible presence of BeF molecule in solar atmosphere. References [1] Zun Lue Zhu, Qing Peng Song, Su Hua Kou, Jian Hua Lang, Jin Feng Sun, Spectroscopic Parameter and Molecular Constant Investigations on Low-Lying States of BeF Radical, Int. J. Mol. Sci., 2012, 13, 2501-2514. DOI: 10.3390/ijms13022501. [2] M. Pelegrini, C.S. Vivacqua, O. Roberto-Neto, F.R. Ornellas, F.B.C. Machado, Radiative Transition Probabilities and Lifetimes for the Band Systems A2  X 2 of the Isovalent Molecules BeF, MgF and CaF, Braz. J. Phys., 2005, 35, 950–956. [3] F.R. Ornellas, F.B.C. Machado, O. Roberto-neto, A Theoretical Study of the Molecules BeF and BeF+ in their Lowest-lying Electronic States, Mol. Phys., 1992, 77, 1169–1185. DOI: 10.1080/00268979200103051. [4] F.A. Jenkins, Fine Structure of the Beryllium Fluoride Bands, Physical Review., 1930, 35, 315335. [5] D.L. Hildenbrand, E. Murad, Mass-spectrometric Determination of the Dissociation Energy of Beryllium Monofluoride, J. Chem. Phys., 1966, 44, 1524–1529.

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[6] M. Farber, R.D. Srivastava, Dissociation Energies of BeF and BeCl and the Heat of Formation of BeClF, J. Chem. Soc. Faraday Trans., 1974, 70, 1581–1589. [7] G. Herzberg, Molecular Spectra and Molecular Structure, Spectra and Diatomic Molecules, Van Nostrand Reinhold, New York, NY, USA, 1950, volume I, p. 402. [8] K.P. Huber, G. Herzberg, Molecular Spectra and Molecular Structure, Constants of Diatomic Molecules, Van Nostrand Reinhold, New York, NY, USA, 1979, volume IV, p. 76. [9] D.R.Bates, The intensity distribution in the nitrogen band systems emitted from the earth's upper atmosphere, Proc. R. Soc., 1949, A196, 217. DOI: 10.1098/rspa.1949.0025. [10] R. Shanmugavel, P. Sriramachandran, Astrophysically useful Radiative Transition Parameters for the e1  X 1 and 1   X 1 Systems of Zirconium Oxide, Astrophys. Space. Sci., 2011, 332, 257–262. DOI 10.1007/s10509-010-0516-6. [11] R. Shanmugavel, S.P. Bagare, N. Rajamanickam, Astrophysically Useful Parameters for Certain Band Systems of BeH, BeD and BeT Molecules, Serb. Astron. J., 2006, 173, 83-87. DOI: 10.2298/SAJ0673083S. [12] P. Sriramachandran, R. Shanmugavel, S.P. Bagare, N. Rajamanickam, Identification of SrF molecular lines in the spectrum of sunspot umbra, Astrophys. Space. Sci., 2009, 323, 41-49. DOI: 10.1007/s10509-009-0043-5. Cite the paper R. Sindhan, P. Sriramachandran, R. Shanmugavel, S. Ramaswamy (2017). Spectroscopic Analysis of Gas Phase Astrophysical Molecule: Beryllium Monofluride. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.60.92.355

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Study of Charge Density and Crystal Structure of co-doped LaCrO3 System58 N. Thenmozhi1, S.Sasikumar2, R. Saravanan2, Yen-Pei Fu3 1 – PG and Research Department of Physics, NMSSVN College, Nagamalai, Madurai - 625 019, India 2 – Research Centre and Post Graduate Department of Physics, The Madura College, Madurai - 625 011, India 3 – Department of materials Science and Engineering, National Dong-Hwa University, Shou-Feng, Hualien 974, Taiwan DOI 10.2412/mmse.99.30.568 provided by Seo4U.link

Keywords: X-ray diffraction, electron density, co-doping, scanning electron microscopy, magnetic property.

ABSTRACT. The co-doped lanthanum chromite system of (La0.8Ca0.2) (Cr0.81Co0.1Cu0.09)O3 sample has been prepared by high temperature solid state reaction technique. The synthesized sample has been characterized for structural, optical, morphological and magnetic properties by powder XRD, UV-vis, SEM/EDS and VSM. Structural analysis revealed that the prepared sample has orthorhombic structure with space group of Pnma. The bonding between the atoms has been analyzed using maximum entropy method (MEM). The bond lengths and mid bond electron densities have been estimated from the 1D electron density profiles. From the optical absorption spectra, the energy band gap of the sample has been calculated as 2.035 eV. From the SEM image, the average particle size of the synthesized sample is 235nm. EDS spectrum of the synthesized sample confirms its purity. Room temperature M-H curves obtained from VSM measurements exhibit predominant antiferromagnetic ordering of the prepared sample. The co-doped LaCrO3 compounds have been primarily used as cathode as well as inter-connector coating materials in solid oxide fuel cells (SOFC).

Introduction. Lanthanum chromite (LaCrO3), a perovskite rare-earth oxide material has been investigated for the past five decades due to their rich and interesting properties and essential technological applications. Since lanthanum chromite has high melting point of 2490 °C with high electronic conductivity, it is often used as electrodes in magneto hydrodynamic (MHD) generators [1] and has also been found for use as oxidation catalyst for soot combustion [2], electric heaters [3] and NOx sensors [4]. Lanthanum chromite is a p-type semiconducting material which exhibits properties like, good physical and chemical stability during the oxidation and reduction process, electro catalytic activity, high thermal expansion coefficient and high mechanical strength [5, 6]. Since the transition metal doped lanthanum chromite has the property of mixed ionic and electronic conductivity, they have been used for electrodes and interconnector materials in solid oxide fuel cell (SOFC) which is a solid electro chemical device, converts chemical energy into electrical energy [7]. Usually, LaCrO3 crystallizes in orthorhombic structure with Pnma space group. The transport properties of lanthanum chromites can be studied by the localized behaviour of the d-electrons [8]. Literature showed various preparation techniques to synthesis lanthanum chromites which include sol-gel method, hydrothermal processing, microwave combustion synthesis, pechini method etc. In the present work, (Co, Cu) doped La-Ca based chromites were prepared through solid state reaction method and we report on structural, optical, morphological and magnetic properties of the synthesized co-doped system. Experimental. Preovskite sample of (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 was prepared through solid state reaction method. Appropriate amounts of high purity (99.99%) of La2O3, CaCO3, Cr2O3, Co3O4 and CuO were mixed with distilled water for 12 h. After dried, these powders were ground and then calcined in air at 1000 °C for 4 h. Thereafter, the calcined samples were pelletized and dry pressed at

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100MPa. These pressed pellets were finally sintered out in air at 1500 °C for 6 h with a programmed heating rate of 5oC/min to get the required samples. To determine the phase purity and sample homogeneity, the sample was characterized by powder Xray diffraction (XRD) at room temperature by X-ray diffractometer (Bruker AXS D8 advance) with CuKα as the incident beam radiation. Optical band gap measurement was carried out using UVvisible spectrometer Cary 5000 (Varian, Germany). The morphological and elemental analyses were done for the prepared sample using scanning electron microscopy (SEM) (JEOL Model JSM 6390LV) equipped with an energy dispersive X-ray (EDS) spectrometer (JEOL Model JED – 2300). Magnetic parameters were taken using vibrating sample magnetometer (Lakeshore VSM 7410) at 300K. Results and discussion. Powder XRD and Rietveld refinement. Figure 1 shows the X-ray diffractogram of the synthesized polycrystalline sample (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3. Sharp XRD peaks with narrow full width at half maximum shows that the crystals are well crystallized. All the XRD peaks in figure 1 could be indexed to orthorhombic crystal lattice of LaCrO3 with JCPDS card number 33-0701. To investigate the structural properties in detail the XRD data is subjected to Rietveld refinement [9] technique using the software JANA 2006 [10]. During the refinement process, the cell parameters, background profile shape, peak shift and preferred orientation were refined and hence the difference between the observed XRD profile and theoretically generated profile is minimized. Refinement of the synthesized sample (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 was carried out in the orthorhombic setting of space group Pnma (space group number: 62) with four molecules per unit cell and the refined profile is presented in figure 2. For the orthorhombic structure, the Wyckoff position for La and Ca atoms is 4C (0.0267, 0.25, -0.004); for Cr, Co and Cu is 4b (0, 0, 0.25); for O1 apex atom is 4C (0.4905, 0.25, 0.0684); for O2 planar atom is 8d (0.2193, 0.5361, 0.2195) [11]. The orthorhombic unit cell of (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 obtained through VESTA is shown in figure 3. It consists of corner linked octahedra CrO6 in which the central Cr atom is surrounded by six oxygen atoms. The La atom is at the space between the octahedra. The refined structural parameters are given in table 1. With the substitution of Ca at La site and (Co, Cu) at Cr site, the volume of the unit cell is decreased when it is compared with the volume of the undoped lanthanum chromite (234.52Å3 from JCPDS # 33-0701). The reason is that the doped Ca2+ (1.34 Å) ions having smaller ionic radii replacing La3+ (1.36 Å) ions and also the doped Cu3+ ions (0.54 Å) [12] having smaller ionic radii replacing the Cr3+ (0.615 Å) [12] ions.

Fig. 1. Raw profile of (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3.

Fig. 2. Fitted profile.

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Fig. 3. The unit cell of obtained from VESTA.

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

Table 1. Structural parameters. Parameters

Values

a (Å)

5.4426(5)

b (Å)

7.6831(2)

c (Å)

5.4631(4)

α=β=γ (º)

Volume (Å3)

228.45(5)

Density (gm/cc)

6.41(8)

Rp (%)

7.03

Robs (%)

4.90

GOF

1.20

F(000)

393

Table 2. EDS elemental composition. Atomic (At %) La

26.64

6.71

23.47

2.61

2.38

31.47

Band gap determination. The optical energy band gap of the prepared compound (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 was determined from UV-visible absorption spectra. Tauc’s equation [13] relates the absorption coefficient (α) and the energy band gap of the material (Eg) as αhν=A (hνEg)n, where hν is the photon energy, A is the proportionality constant, n= 1/2 for direct band gap materials and n=2 for indirect band gap materials. A graph is drawn by taking (hν) along the X-axis and (αhν)2 along the Y-axis as shown in figure 4. From this Tauc plot, the extrapolation of the linear portion of the curve to X-axis, gives the energy band gap. The energy band gap obtained for the synthesized sample from Tauc plot is 2.035 eV. SEM/EDS analysis. The surface morphology of the synthesized sample was analyzed through its SEM image which is shown in figure 5. It shows the presence of the particles of different sizes which are heterogeneously distributed. The particle sizes were in the range of 230nm-240nm. Figure 6 represents the EDS spectra of the prepared co-doped sample. Peaks in EDS spectrum indicate the different elements (La.Ca, Cr, Co, Cu and O) present in the sample. The elemental composition in at% is given in table 2 and it confirms the purity of the sample.

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Fig. 4. UV-Visible plot.

Fig. 5. SEM image.

Fig. 6. EDS spectra. Magnetic property. Lanthanum chromite is G-type antiferromagnetic material with Neel temperature TN = 282K and at room temperature, it behaves as a poor electrical conductor [14]. The synthesized sample (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 was analyzed for magnetic studies using VSM. The M-H loop recorded at room temperature is shown in figure 7 and the magnetic parameters are

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given in table 3. The M-H loop does not show any hysteresis and the observed low value of magnetization indicates that the sample is attributed to antiferromagnetism due to Cr 3+ spins. Table 3. Magnetic parameters from VSM measurements. Parameters

values

Ms ×10-3 (emu g-1)

2.52

Hc (G)

473.36

Mr ×10-3 (emu g-1)

42.543

Fig. 7. M-H curve.

Fig. 8. Three dimensional electron density isosurface. Charge density analysis by MEM. The charge density distribution around La-O and Cr-O bonds of the synthesized sample (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 was analyzed using maximum entropy method (MEM) [15], which uses the cell parameters and structure factors extracted from Rietveld method [9]. MEM method is used to study about the bonding behaviour of any crystalline material. MEM computations were implemented by the software PRIMA [16]. For our calculation, the unit

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cell was divided into 48×64×48 pixels. The resultant electron density distribution in the orthorhombic unit cell was visualized using VESTA [17], the visualization software.

Fig. 9. 3D unit cells of (La0.8Ca0.2)(Cr0.87Co0.1Cu0.03)O3 with a) (101) and c) (020) planes shaded. Two dimensional electron density distribution on b) (101) and d) (020) planes for (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3. Figure 8 illustrates the three dimensional electron density distributions in the unit cell of the prepared sample with the iso-surface level 3.0 e/Å 3. In the 3D unit cell, the La, Cr amd O atoms are clearly seen and the picture confirms the orthorhombic phase of the synthesized sample. Figures 9a and 9c denote the 3-dimensional orthorhombic unit cell with (101) and (020) planes shaded. To analyze the bonding behaviour, the 2D electron density contour maps for these two significant crystallographic planes (101) and (020) were displayed as figures 9b and 9d. These maps are drawn in the range 0-1.0 e/Å 3 with the contour interval of 0.04 e/Å 3. From figure 9b, it can be observed that there is no charge sharing taking place between La and O2 atoms which means that the bond La-O2 has ionic nature. Figure 9d indicates that, there is a presence of bond charges along the path between Cr and O2 atoms which shows the bond Cr-O2 has covalent nature. To estimate the mid bond electron densities for the bonds, the 1D electron density profiles were drawn. Figures 10a and 10b are the 1D line profiles for La-O2 and Cr-O2 bonds respectively. The bond length and mid bond electron density values are given in table 4. The mid bond electron density for La-O2 bond is 0.4801 e/Å 3 and the bond length is 2.4462 Å . The mid bond electron density value for La-O2 bond confirms that the bond is less ionic in nature. The bond length for Cr-O2 bond is 1.9618 Å . The mid bond electron density value for Cr-O2 is 0.2786 e/Å 3 which confirms that the bond is less covalent in nature. Hence, for the prepared sample, the bond La-O2 is less ionic and the bond Cr-O2 is less covalent. The bond length values agree well with the reported values [18, 19]. The decrease in covalent character of Cr-O2 bond may attribute to the antiferromagnetic nature of the synthesized sample. Figure 10c shows the 1D map for O1-O2 bond. The mid bond density value for O1-O2 bond confirms that the bond has the ionic nature with partly covalent character.

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Fig. 10. One dimensional electron density profiles along a) La and O2 b) Cr and O2 c) O1 and O2 atoms in (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3. Table 4. Bond lengths and mid bond electron densities for La-O2, Cr-O2 and O1-O2 bonds for (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3. Bonding La-O2

Cr-O2

O1-O2

Bond length (Å)

Mid bond electron density (e/Å3)

Bond length (Å)

Mid bond electron density (e/Å3)

Bond length (Å)

Mid bond electron density (e/Å3)

2.4462

0.4801

1.9618

0.2786

2.7500

0.3661

Summary. Single phased (La0.8Ca0.2)(Cr0.81Co0.1Cu0.09)O3 ceramic sample was synthesized by conventional solid state reaction technique at 1500 ºC for 6 h. The powder X-ray diffraction pattern showed that the prepared sample has orthorhombic perovskite structure with space group Pnma. MEM charge density analysis reveals that the bond La-O2 is less ionic and the bond Cr-O2 is less covalent in nature. The optical energy band gap of the sample using UV-visible absorption spectrum is found to be 2.035 eV. Particles of different sizes are visualized through SEM image. Stoichiometry of the synthesized sample was confirmed by EDS spectral analysis. Room temperature VSM measurements confirm the antiferromagnetic behavior of the grown sample. Acknowledgements. We acknowledge SAIF, Cochin University, India for their help in the collection of X-ray diffraction data, UV-Visible spectra and SEM/EDS spectra. We acknowledge SAIF, IIT Madras, Chennai, for the VSM measurements. References [1] D. B. Meadowcroft, Some properties of strontium-doped lanthanum chromite, Brit. J. Appl. Phys., 2, 1225 (1969). DOI: http://dx.doi.org/10.1088/0022-3727/2/9/304 [2] S. Ifrah, A. Kaddomi, P. Gelin, G. Bergeret, On the effect of La-Cr-O phase composition on diesel soot catalytic combustion, Catal. Commun., 8, 2257 (2007). DOI: http://dx.doi.org/10.1016/j.catcom.2007.04.039 [3] A. Suvorov and A. P. Shevchik, A Heating Module Equipped with Lanthanum Chromite-Based Heaters, Refract. Ind. Ceram., 45, 196 (2004). DOI:10.1023/B:REFR.0000036729.24986.e3 [4] W. L. David, F. C. Montgomery, T. R. Armstrong, NO-selective” NOx sensing elements for combustion exhausts, Sens. Actuators B 111-112, 84 (2005). DOI:http://dx.doi.org/10.1016/j.snb.2005.06.043. [5] F. Heydari, A. Maghsoudipour, M. Alizadeh, Z. Khakpour and M. Javaheri, Synthesis and evaluation of effective parameters in thermal expansion coefficient of Ln0.6Sr0.4Co0.2M0.8O3−δ (Ln = MMSE Journal. Open Access www.mmse.xyz

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La,Nd and M = Mn,Fe) perovskite oxide, Bull. Mater. Sci. 38, 1009 (2015). DOI:10.1007/s12034015-0942-8 [6] G. Setz Luiz Fennando, H. Sonia Regina, Mello Castanho, Determining the Lanthanum Chromite Zeta Potential in Aqueous Media, Mater. Sci. Forum, 660-661, 1145 (2010). DOI:10.4028/www.scientific.net/MSF.660-661.1145 [7] M. Suzuki, H. Sasaki, A. Kajimura, Oxide ionic conductivity of doped lanthanum chromite thin film interconnectors, Solid State Ionics, 96, 83 (1997). DOI:http://dx.doi.org/10.1016/S01672738(97)00007-6 [8] Yen Pei Fu, Hsin-Chao Wang, Shao-Hua Hu, Kok-Wan Tay, Electrical conduction behaviors of isovalent and acceptor dopants on B site of (La0.8Ca0.2)CrO3-δ peroskites, Ceram. Int., 37 2127 (2011). DOI: 10.1016/j.ceramint.2011.02.028 [9] H.M. Rietveld, A Profile Refinement Method for Nuclear and Magnetic structures, J. Appl. Crystallogr. 2 65 (1969). DOI: http://dx.doi.org/10.1107/S0021889869006558 [10] V. Petricek, M. Dusek, L. Palatinus, Jana 2006, The Crystallographic Computing System, Institute of Physics, Prague, Czech Republic, (2006). [11] K.P. Ong, Peter Blaha, Ping Wu, Origin of the light green color and electronic ground state of LaCrO3, Phys. Rev. B, 77, 073102 1 (2008). DOI: https://doi.org/10.1103/PhysRevB.77.073102 [12] R.D. Shannon, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides, Acta Cryst., A 32, 751 (1976). DOI: https://doi.org/10.1107/S0567739476001551 [13] J. Tauc, R. Grigorvici, A. Vancu, Optical Properties and Electronic Structure of Amorphous Germanium, Phys. Status Solidi (b), 15, 627 (1966). DOI: http://dx.doi.org/10.1002/pssb. 19660150224 [14] J.P. Gonjal, R. Schmidt, J.J. Romero, D.U. Amador and E. Moran, Microwave-Assisted Synthesis, Microstructure, and Physical Properties of Rare-Earth Chromites, Inorg. Chem., 52, 313 (2013). DOI:http://dx.doi.org/10.1021/ic302000j [15] R. Shukla, J. Manjanna, A.K. Bera, S.M. Yusuf, and A.K. Tyagi, La 1-xCexCrO3 (0.0 ≤x≤1.0): A New Series of Solid Solutions with Tunable Magnetic and Optical Properties, Inorg. Chem. 48, 11691 (2009). DOI: 10.1021/ic901735d [16] A. D. Ruben, I. Fugio, Superfast program PRIMA for the Maximum Entropy Method, Advanced Materials Laboratory, National Institute for Material Science, Ibaraki, Japan (2004), 3050044. [17] K. Momma, F. Izumi, VESTA: a three-dimensional visualization system for electronic and structural analysis, J. Applied Crystallogr. 41 653 (2008) DOI:http://dx.doi.org/10.1107 / S0021889808012016 [18] C.S. Montross, Elastic Modulus Versus Bond Length in Lanthanum Chromite Ceramics, J. Eur. Ceram. Soc., 18, 353 (1997). DOI:http://dx.doi.org/10.1016/S0955-2219(97)00143-X [19] S. Natsuko, F Helmer, C. Hauback, Structural, Magnetic and thermal properties of La 1tCatCrO3, J. of Solid state Chem., 121, 202 (1996). DOIi:10.1006/jssc.1996.0029 Cite the paper N. Thenmozhi, S.Sasikumar, R. Saravanan, Yen-Pei Fu (2017) Study of Charge Density and Crystal Structure of co-doped LaCrO3 System. Mechanics, Materials Science & Engineering, Vol 9. DOI 10.2412/mmse.99.30.568

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Electrical Properties of Ni0.4Mg0.6Fe2O4 Synthesized by Conventional Solid-State Reaction Method59 K.T. Veeranjaneaya1, D. Ravinder1, 2, a 1 – Department of Physics, National college, Bagepalli, Chikkaballapura (district), Karnataka-561207, India 2 – Department of Physics, Osmania University, Hyderabad- 500 007, Telangana, India a – ketivi@gmail.com DOI 10.2412/mmse.28.98.879 provided by Seo4U.link

Keywords: ferrites, sintering, X-ray diffractometer, AC-electrical conductivity. ABSTRACT. Ni0.4Mg0.6Fe2O4 samples are prepared by conventional double sintering approach and sintered at 1300 oC/ 2 h. These ferrites are characterized using X-ray diffractometer. The diffraction study reveals that the present compound shows perfect single phase cubic spinel structure. In addition, the behavior of distinct electrical properties such as dielectric constant (ε'), dielectric loss (ε") and ac-conductivity (σac) as a function frequency as well as temperature is analyzed using the LCR controller.

Introduction. The field of ferrites is well focused due to their potential applications as storage devices, magnetic sensors, refrigeration, photo-catalysis, drug delivery systems, magnetic resonance imaging, transformers, and inductors, shielding devices, anode materials, spintronic and electronic devices. These applications are attributed to the various electrical and magnetic properties of ferrites [1-7]. Recently several researchers investigated electrical and magnetic properties of NiMg ferrites using various techniques such as citrate-gel [2, 3], self-combustion sol-gel [4], egg-white precursor [5], chemical co-precipitation [8, 9], self-combustion sol-gel [10] and microwave sintering techniques [1]. All these techniques well focused on reporting the various electrical and magnetic properties and these properties are dependent of grain size, cation distribution, sintering condition, sintering method, bulk density and purity of ferrites [1]. In view of this Berchmans et al. [2, 3] reported that the ferrite composition Ni0.4Mg0.6 Fe2O4 can be used as a green anode material as it showed a high electrical conductivity value of 0.6 S/cm. It is well known fact that the ac-conductivity (σac) is a dependent parameter of dielectric constant (ε'), dielectric loss (ε"), frequency and temperature [11, 12]. Hence, we focused report the effect of temperature and frequency on (ε'), (ε") and (σ ac) of Ni0.4Mg0.6Fe2O4 composition via conventional solid state reaction method. Experimental Procedure. Ni0.4Mg0.6 Fe2O4 is prepared by conventional double sintering method. The raw materials NiO, MgO and Fe2O3 are weighed and mixed according to the stoichiometric ratio. The resultant powders are grinded in agate motors for 15 h. Furthermore, the powders are pre-sintered at a temperature of 1200oC for 14 h. in conventional furnace. The pre-sintered samples are crushed into fine powder. The powder is mixed with polyvinyl alcohol (PVA) as a binder and pressed into pellets (10 mm diameter) applying 3 ton pressure. These are sintered at 1300oC for 2 h in a conventional furnace. The sintered samples are characterized using X-ray Diffractometer (Bruker XRay Powder Diffractometer, CuKα, λ = 0.15418 nm) for structural investigation. HIOKI 3532-50 LCR HiTESTER (Japan) is used for studying the electrical properties.

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Results and Discussion. The variation of intensity (I) as a function of two-theta (2θ) angle for Ni0.4Mg0.6 Fe2O4 is shown in Fig.1. The reflection planes indexed in diffraction pattern show the formation cubic spinel structure. These are in well agreement with the standard JCPDS file number: 74-1913. The (311) plane shows the maximum intensity of 8000 among all cubic phase. The average crystallite size (D) of (311) plane is (96 nm) calculated using the Scherrer formula [13, 14]:

Fig. 1. XRD pattern of Ni0.4Mg0.6Fe2O4.

Fig. 2. SEM photos of Ni0.4Mg0.6Fe2O4.

The lattice constant is evaluated using a standard formula: a = (h2+ k2+ l2)1/2. The attributed value is of 0.8376 nm which is almost in close agreement with the reported lattice constant 0.839 nm by Naidu et al. [1]. The x-ray density ρx is calculated by an equation: ρx= 8M/Na3 where M is the molecular weight, N is the Avogadro’s number (6.023x1023 atoms/mole) and ‘a’ is the lattice parameter computed. The result showed that it is order 4.925 g/cm3. The bulk density ρ b is evaluated by using the Archimedes principle and it is found to be 4.023 g/cm3. Furthermore, the porosity is calculated using the relation P = 1-(ρb/ρx) and it is of 18.3 %. The low percentage of porosity expresses a fact that the ferrite sample is of high pure in nature. It is obvious from Fig. 2 that the spherical shaped grains are uniformly distributed within the 10 micron area of the spot on the pellet surface. The average grain size (Ga) is found to be 2.68 μm using linear intercept method [15]. Fig.3 shows the variation of dielectric constant as a function of temperature at different frequencies. It is seen from the figure that the ferrite composition performs a steady trend during 300 to 500 K temperatures for the selected frequencies. This can be happened due to unavailability of ferrous ions at octahedral B-sites [2]. In addition, the high value of dielectric constant is established at lower frequency and it is low at higher frequencies. The Maxwell-Wagner interfacial or space charge polarization is also responsible for this manner [19]. The similar behavior is observed in the literature [16-18]. The ferrite expresses a small step like increase of dielectric constant at 700 K for 50 kHz and 0.1 MHz frequencies. This is because of jumping of charge carriers at that particular temperature. The loss is also performing the similar trend as that of dielectric constant as shown in Fig. 4. In over all the ferrite composition reveal low value of dielectric constant and loss at higher frequencies. This may be useful for low noise device applications [20, 21].

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Fig. 3. Temperature Vs. dielectric constant.

Fig. 4. Temperature Vs. dielectric loss.

Fig. 5 shows the temperature and frequency dependence of ac-conductivity of present ferrite composition. The lnĎ&#x192; versus 103/T plots as shown in Fig.6 are drawn to find the ac-activation energies of ferrite composition at selected frequencies. In the lnĎ&#x192; versus 10 3/T plots two slopes are observed. There are different reasons behind performing two slopes or activation energies. Manjula et al. [22] reported that two slopes are because of change of conduction mechanism before and after Curietransition temperature (Tc). Islam et al [23] and Hiti [24] revealed that the slope of gradient line must change on passing through Tc due to change of exchange interaction between inner and outer electrons at Curie-transition temperature. The activation energies corresponding to the two slopes are evaluated and listed in Table.1. It is seen that ac activation energies are decreasing with increasing of frequency which may be due to increase of ac-conductivity. The activation energies in paramagnetic region (E 1) are higher than those in ferri magnetic region (E 2) (Table.1). Moreover, the change of activation energies can be attributed to the change of conduction mechanism from polaron to hopping as reported by Gabal et al. [5]. The lower activation energies (E 2) are attributed to magnetic disordering owing to limited availability of charge carriers [6].

Fig. 5. Temperature Vs. ac-conductivity.

Fig. 6. Arrhenius plots of Ni0.4Mg0.6Fe2O4.

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Table 1. The two region activation energies at selected frequencies. Frequency 50 kHz 0.1 MHz 0.5 MHz 1 MHz 3 MHz

E1 (eV) (I) 0.439 0.410 0.382 0.318 0.293

E2 (eV) (II) 0.271 0.259 0.211 0.174 0.146

The variation of logarithm of ac-conductivity as a function of logarithm of angular frequency at selected temperatures is shown in Fig.7. It is understood from logσ versus logω plots that the total acconductivity is the combination of two terms [6]: σac (ω, T) = σdc (T) + σac (ω)

(2)

where the first term is (DC-electrical conductivity) temperature dependent and independent of frequency. The exponent values show that ‘n’ values are achieved to be 0.592, 0.551, 0.398, 0.356, 0.284 & 0.270 for 308, 373, 473, 573, 673 & 773 K respectively.

Fig. 7. Frequency dependence of ac-conductivity. Summary. Ni0.4Mg0.6Fe2O4 ceramic samples are prepared by conventional double sintering technique. The low dielectric constant and low loss obtained for the present composition is useful for low noise device applications. Two different activation energies reveal the change of conduction mechanism from polaron to hopping conduction. References [1] K. Chandra Babu Naidu, W. Madhuri, Journal of Magnetism and Magnetic Materials 420 (2016) 109–116 [2] L. J. Berchmens, R. K. Selvan, P. N. S. Kumar, C. O. Augustin, Journal of Magnetism Magnetic Materials 279 (2004) 103-110 [3] L. J. Berchmens, R. K. Selvan, C. O. Augustin, Materials Letters 58 (2004) 1928-1933

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[4] Z. V. Mocanu, M. Airimioaei, C. E. Ciomaga, L. Curecheriu, F. Tudorache, S. Tascu, A. R. Iordan, NN. M. Palamaru, L. Mitoseriu, Journal of Material Science 49 (2014) 3276-3286 [5] Chandra Babu Naidu K., Madhuri W, Materials Chemistry and Physics 181 (2016) 432-443 [6] K. Chandra Babu Naidu and W. Madhuri, International Journal of Applied Ceramic Technology, 1–6 (2016), DOI:10.1111/ijac.12571 [7] H. Moradmard, S. F. Shayeshtech, P. Tohidi, Z. Abbas, M. Khalegi, Journal of Alloys and Compounds 650 (2015) 116-122 [8] M. Naeem, N. A. Shah, I. H. Gul, A. Maqsood, Journal of Alloys and Compounds 487 (2009) 739-743 [9] Mirela Airimioaei, Mircea Nicolae Palamaru, Alexandra Raluca Iordan, Patrick Berthet, Claudia Decorse, Lavinia Curecheriu and Liliana Mitoseriu, Journal of American Ceramic Society 97 (2014) 519–526 [10] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, P. Sreenivasula Reddy, D. Jhansi Rani and T. Subbarao, Journal of The Australian Ceramic Society 52 (2016) 95 – 101 [11] K. Chandra Babu Naidu, T. Sofi Sarmash, V. Narasimha Reddy, M. Maddaiah, P. Sreenivasula Reddy and T. Subbarao, Journal of The Australian Ceramic Society 51 (2015) 94 – 102 [12] V. Narasimha Reddy, K. Chandra Babu Naidu, T. Subba Rao, Journal of Ovonic Research 12 (2016) 185- 191 [13] M. Maddaiah, A. Guru Sampath Kumar, L. Obulapathi, T. Sofi Sarmash, K. Chandra Babu Naidu, D. Jhansi Rani, T. Subba Rao, Digest Journal of Nano materials and Biostructures 10 (2015) 155-159 [14] M. Maddaiah, K. Chandra Babu Naidu, D. Jhansi Rani, T. Subbarao, Journal of Ovonic Research 11 (2015) 99-106 [15] M.R. Bhandare, H.V. Jamadar, A.T. Pathan, B.K. Chougule, A.M. Shaikh, Journal of Alloys and Compounds 509 (2011) L113–L118 [16] K. Chandra Babu Naidu, T. Sofi Sarmash, M.Maddaiah, V.Narasimha Reddy and T.Subbarao, AIP Conference Proceedings 1665 (2015) 040001; doi: 10.1063/1.4917614 [17] K. C. Babu Naidu, T.Sofi Sarmash, M. Maddaiah, A. Gurusampath Kumar, D. Jhansi Rani, V. Sharon Samyuktha, L. Obulapathi, T.Subbarao, Journal of Ovonic Research 11 (2015) 79-84 [18] D Kothandan, R. Jeevan Kumar, Journal of The Australian Ceramic Society 52 (2016) 156-166 [19] S. Anil Kumar, K. Chandra Babu Naidu, International Journal of ChemTech Research 9(1) (2016) 58-63 [20] S. Prathap, K. Chandra Babu Naidu, and W. Madhuri, AIP Conference Proceedings 1731 (2016) 030019; doi: 10.1063/1.4947624015 [21] R. Manjula, V.R.K. Murthy, J. Sobhanadri, Journal of Applied Physics 59 (1986) 2929–2931 [22] R. Islam, M.A. Hakim, M.O. Rahman, H. Narayan Das, M.A. Mamun, Journal of Alloys and Compounds 559 (2013) 174–180 Cite the paper K.T. Veeranjaneaya, D. Ravinder (2017). Electrical Properties of Ni0.4Mg0.6Fe2O4 Synthesized by Conventional Solid-State Reaction Method. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.28.98.879

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Synthesis and Characterization of PbZrTiO3 Ceramics60 T. Vidya Sagar1,a, T. Sofi Sarmash1, M. Maddaiah1 , T. Subbarao1 1 – Materials Research Laboratory, Dept. of Physics, Sri Krishna Devaraya University, Anantapur – 515 003, India a – tvidyasagar83@gmail.com DOI 10.2412/mmse.52.81.553 provided by Seo4U.link

Keywords: lead zirconate titanate, dielectric constant, diffraction, ferroelectric material.

ABSTRACT. Lead zirconate titanate (PZT) ceramic powders were prepared via conventional solid-state reaction method. The prepared samples were sintered at 900oC for 2 h. The sintered materials were characterized for structural analysis. The diffraction pattern reveals the pure phase formation of perovskite PZT structure. The morphology is analyzed by scanning electron microscope and average grain size is evaluated to be of 3.3 μm. The frequency and temperature dependence of electrical properties such as dielectric constant and dielectric loss was studied using LCR controller. In addition, the ferroelectric behavior was investigated by P-E loop tracer.

Introduction. Lead titanate is a ferroelectric ceramic material. It shows distinct applications in various fields and is used for non volatile memories, medical ultrasound imaging and actuators and data storage devices [1, 2]. The well populated applications of ferroelectric materials are observed in the fields of dielectrics for capacitor applications. In particular, these materials are candidates for ferroelectric thin film technology. The perovskite materials will have a general chemical formula of the type ABO3 [2]. Many ferroelectric materials such as; barium titanate (BaTiO 3), lead titanate (PbTiO3), lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), have this perovskite type structure. These materials can work as good dielectric materials. In addition, the barium titanate, strontium titanate, strontium copper titanate, strontium lanthanum titanate, strontium lead titanate, strontium zinc manganese titanate, strontium magnesium titanate and strontium bismuth titanate are investigated recently for the dielectric and ferroelectric properties by several researchers [3-9]. In the current study, the structure, morphology, dielectric and ferroelectric behaviour are discussed for PZT ceramics. Experimental Procedure. In this study the precursors are chosen as PbO, ZrO2 (99.6% purity, Sigma Aldrich), TiO2 (99.4% purity, Sigma Aldrich) to prepare the ferroelectric PZT ceramics. Initially, the raw materials are weighed and mixed uniformly according to their stoichiometric ratio. The mixed powder is ball milled for approximately 12 h using ball miller (Retsch PM200. Furthermore, the uniformly grounded powder is pre-sintered at 700oC for 12 hr. The pre-sintered powder is again grounded for nearly 2 hr. The pellets of radius 0.58 cm and thickness 0.282 cm are prepared after applying 2 ton pressure using hydraulic press. The pellets are sintered at 850 oC for 2 hr in conventional furnaces. Further, the pellets are characterized using XRD at room temperature (Bruker X-Ray Powder Diffract Meter, CuKα = 0.15418 nm), SEM (Hitachi: S-4700), LCR controller (Hioki 3532-50) and P-E loop measurement (Marine India) for structural, surface morphological, dielectric and ferroelectric properties respectively. Results and Discussions.

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Structural Analysis. The diffraction pattern of PZT ceramic powder is shown in Fig.1. It can be understood from figure that the formed single crystalline phases that belong to cubic perovskite structure of pure lead zirconate titanate. The maximum intense plane is noticed at the diffraction or two-theta angle of 32.254o. The value of lattice parameters â&#x20AC;&#x2122;câ&#x20AC;&#x2122; of PZT ceramic composition were found to be 4.131 Ă&#x2026; where as â&#x20AC;&#x153;a = bâ&#x20AC;? is 4.088 Ă&#x2026; conforming the tetragonal perovskite structure. Furthermore, the average crystalline size (D) is calculated as 41.2 nm using the Scherer formula [1013].

Fig. 1. PZT perovskite structure.

Fig. 2. SEM image of PZT. Surface Morphology. The Scanning Electron Microscope (SEM) provides the surface morphology of powder specimen. It is seen from Fig. 2 that all the grains are of almost spherical in shape. The average grain size (Ga) is found to be 3.3 Âľm using linear intercept method using the following equation [14].

Ga=

1.5 đ??ż đ?&#x2018;&#x20AC;đ?&#x2018;

(1)

where L is the test line length, N is the number of intersecting grains and M is the magnification. SEM image of the PZT sample prepared is shown in Fig. 2. It contains well defined grains of spherical in shape. Moreover, an apparent porosity is observed to be very small. MMSE Journal. Open Access www.mmse.xyz

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Fig. 3. The Dielectric constant versus temperature plot.

Fig. 4. The Dielectric loss versus temperature plot.

Dielectric Properties. The variation of dielectric constant (ε') and loss (ε") of PbZrTiO 3 is shown in Fig.3 and Fig. 4 respectively as a function of both frequency (100 Hz- 1 MHz) and temperature (300573 K). It is understood from the figures that the dielectric constant and loss were slowly increasing with increase of temperature up to 573 K and further a sharp increasing trend in both the cases was observed. The sharp increase is attributed to the interfacial or space-charge polarization effect. Similar trend is observed in the literature [15-18]. In addition, ε' and ε" were decreasing with increase of frequency. This was happened due to in effective space-charges at the grain boundary interface. At room temperature for frequency ~ 1 MHz the present specimen showed dielectric constant of ~15. The loss was also showing the similar trend as that of permittivity in all respects. But interestingly, loss versus temperature plot shows dielectric relaxations with increase of temperature. The relaxation is shifted towards the right. These relaxations are generally formed due to the presence of oxygen vacancies with temperature. The high loss of 14 is attributed at 1 MHz frequency. This kind of high ε' and high ε" values noticed at room temperature were most suitable for filter, charge stored capacitors and absorber applications. Ferroelectric properties. The ferroelectric behavior of PZT is investigated with the help of P-E loop tracer. While doing measurement the pellet is connected parallel to 2 µF capacitor for compensation. Fig. 5 depicts the ferroelectric hysteresis loops of PZT under an applied frequency of 600 Hz at an operating voltage of 600 V. It is understood from Fig.5 that the sample shows a well-behaved hysteresis loop distorted into ‘banana’ shape performed at distinct temperatures such as 303K.. The response of dipoles per unit field is in general regarded as polarization. It is an observed fact that the saturation polarization (Ps) and remanance polarization (Pr) of PZT at all temperatures is found to be constant value of ≈ 21.33 μC/cm2 and coactivity field (Ec) is 0.79 Kv/Cm.

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Fig. 5. PE loop of PZT Sample. Summary. Lead zirconate titanate (PZT) ceramic powders were prepared via conventional solid-state reaction method. The diffraction pattern reveals the pure phase formation of perovskite PZT structure. The average crystallite diameter is of 41.2 nm. The average grain size is evaluated to be of 3.3 micrometer. The high dielectric constant and high dielectric loss was observed for dielectric absorbers applications. The P-E loop analysis showed the highest Ps of 21.3 µC/Cm2 coactivity field (Ec) is 0.79 Kv/Cm. References [1] K.Chandra Babu Naidu, T.Sofi Sarmash, M.Maddaiah, A. Gurusampath Kumar, D. Jhansi Rani, V. Sharon Samyuktha, L. Obulapathi, T.Subbarao,” Structural and electric properties of PbO- doped SrTiO3 Ceramics” Journal of Ovonic research 11 (2015) 79 - 84. [2] V. Narasimha Reddy, T. Sofi Sarmash, K. Chandra Babu Naidu, M. Maddaiah, T. Subbarao, Structural and Optical Properties of BaO-ZnO-TiO2 Ternary System, Journal of Ovonic Research 12 (2016) 261-266. [3] K.Chandra Babu Naidu, T.Sofi Sarmash, V. Narasimha Reddy, M. Maddaiah, P. Sreenivasula Reddy, T.Subbarao, Structural, dielectric and electrical properties of La 2O3 doped SrTiO3 ceramics,” Journal of The Australian Ceramic Society, 51 (2015) 94 – 102. [4] K. Chandra Babu Naidu, T.Sofi Sarmash, M.Maddaiah, P.Sreenivasula Reddy, D. Jhansi Rani T. Subbarao,” Synthesis and Characterization of MgO doped SrTiO 3 Ceramics”, Journal of The Australian Ceramic Society 52 (2016) 95 – 101. [5] K. Chandra Babu Naidu, T. Sofi Sarmash, V.Narasimha Reddy, M. Maddaiah and T. Subbarao, Structural and Dielectric Properties of CuO doped SrTiO 3 Ceramics”, American Institute of Physics proceedings 1665 (2015) 040001; doi: 10.1063/1.4917614. [6] M. Maddaiah, A. G. Kumar, L. Obulapathi, T. S. Sarmash, K. Chandra Babu Naidu, D. J. Rani, T. S. Rao,” Synthesis And Characterization Of Strontium Doped Zinc Manganese Titanate Ceramics “ digest journal of nanomaterials and biostructures, 10 (2015) 155-159. [7] M.Maddaiah, K.Chandra Babu Naidu, D. Jhansi Rani, T. Subbarao,“Synthesis and Characterization of CuO-Doped SrTiO3 Ceramics”, Journal of Ovonic Research 11 (2015) 99 - 106. [8] S. Anil Kumar and K.Chandra Babu Naidu, Structural and Dielectric Properties of Bi 2O3 Doped SrTiO3 Ceramics”, International Journal of ChemTech Research 9 (2016) 58-63.

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[9] V. Narasimha Reddy, K. Chandra Babu Naidu, T. Subba Rao, Structural, Optical and Ferroelectric Properties of BaTiO3 Ceramics, Journal of Ovonic Research 12 (2016) 185- 191 [10] D Jhansi Rani, A Guru Sampath Kumar, T Sofi Sarmash, K Chandra Babu Naidu, M Maddaiah, T Subba Rao, Effect of Argon/Oxygen Flow Rate on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films, Journal of the Minerals, Metals and Materials Society 68 (2016) 1647-1652. [11] K. Chandra Babu Naidu and W. Madhuri, Microwave Processed NiMg Ferrites: Studies on Structural and Magnetic Properties, Journal of Magnetism and Magnetic Materials 420 (201) 109116. [12] K. Chandra Babu Naidu and W. Madhuri, Effect of non-magnetic Zn2+ cations on initial permeability of microwave treated NiMg ferrites, International Journal of Applied Ceramic Technology 13 (2016) 1090-1095. [13] S. Prathap, K. Chandra Babu Naidu, and W. Madhuri, Ferroelectric behaviour of Microwave sintered iron deficient PbFe12O19-Î´, AIP Conference Proceedings 1731 (2016) 030019; doi: 10.1063/1.4947624 [14] K. Chandra Babu Naidu and W. Madhuri, Microwave Assisted Solid State Reaction Method: Investigations on Electrical and Magnetic Properties NiMgZn Ferrites, Materials Chemistry and Physics 181 (2016) 432-443. [15] K. Chandra Babu Naidu, S. Roopas Kiran and W. Madhuri, Microwave Processed NiMgZn Ferrites for Electromagnetic Interference Shielding Applications, IEEE Transactions on Magnetics (2016), DOI: 10.1109/TMAG.2016.2625773 [16] K. Chandra Babu Naidu, W. Madhuri, Microwave Processed Bulk and Nano NiMg Ferrites: A Comparative Study on X-band Electromagnetic Interference Shielding Properties, Materials Chemistry and Physics 187 (2017) 164-176. [17] K. Chandra Babu Naidu, W. Madhuri, Effect of Microwave Heat Treatment on Pure Phase Formation of Hydrothermal Synthesized Nano NiMg ferrites, Phase Transitions (2016), doi:10.1080/01411594.2016.1277220 Cite the paper T. Vidya Sagar, T. Sofi Sarmash, M. Maddaiah, T. Subbarao (2017). Synthesis and Characterization of PbZrTiO3 Ceramics. Mechanics, Materials Science & Engineering, Vol 9. 10.2412/mmse.52.81.553

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Effect of Multiple Laser Shock Peening without Coating on Al-2024-O Alloy for Automotive Applications 61 Yash Jain1, Sandeep Varin1, S. Prabhakaran2, S. Kalainathan2 1 – School of Mechanical Engineering, VIT University, Vellore – 632 014, India 2 – Centre for Crystal Growth, VIT University, Vellore - 632 014, India DOI 10.2412/mmse.65.57.424 provided by Seo4U.link

Keywords: laser shock peening without coating (LSPwC), hardness, X-ray diffraction, roughness, residual stress, surface morphology.

ABSTRACT. The present work discusses the influence of surface compressive residual stress induced by multiple laser shock peening without coating process using low energy Nd: YAG laser with the fundamental wavelength. Laser shock peening without absorbent coating (LSPwC) was employed to Al-2024 in order to improve its surface microstructure and mechanical properties. The compressive residual stress measurements are accomplished according to X-ray diffraction sin2Ψ method. The surface morphology and roughness analysis were carried out using atomic force microscope and roughness profilometer respectively. Also, the microstructure analysis was performed using an optical microscope and scanning electron microscope. The Vickers micro-hardness revealed the improvement of surface and sub-surface hardness after multiple laser shock peening without coating process using low energy laser.

Introduction. Laser shock peening is a recently developed advanced surface modification technology which has been very effective in improving strength, wear, hardness, roughness and corrosion resistance of metallic materials. It is cold deformation process where pulses hit the surface through high power intensity and shock waves are generated. Laser shock peening (LSP) utilizes high energy laser pulses to impact the surface of the metallic material covered with a transparent confinement layer (usually water). When a laser pulse of sufficient intensity is imparted on the material, the absorbent layer is vaporized. The vapor absorbs the remaining laser energy and is heated and ionized into a high pressurized plasma. The transparent confinement layer amplifies the plasma pressure which propagates into the metallic material as a shock wave. In turn, shock wave will lead to plastic deformation which will lead to compressive stresses being induced in the surface layers of the metallic material, provided the plasma pressure is of sufficient magnitude to exceed the elastic limit of the metal. Due to the shock waves thus generated, the dislocation density considerably increases and therefore the resistance offered for external load also increases. The increasing compressive stress value will significantly increase the mechanical properties of the surface layer such as hardness, strength, wear and roughness compared to the conventional shot peening, Laser shock peening (LSP) can induce far deeper compressive residual stresses, better surface finish and uniform distribution of intensity across the surface. LSP also improves the crack growth resistance post foreign object damage (FOD) with delayed crack initiation i.e. LSP decreases the crack growth rate to a substantial amount. Aluminum alloys are widely used in automotive and aerospace industries because of their light weight and high strength to weight ratio. Considerable research has been carried out to examine the effects of LSP on the mechanical properties of aluminium alloys. Most of the research showed that the mechanical properties improved significantly for aluminium alloys due to the compressive residual © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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stresses after surface modification technique. The objective of this work is to examine the effects of LSPwC, change in microstructure, microhardness of Al-2024 alloy. EXPERIMENT AND PROCEDURE Experimental material. The chemical composition of Al-2024 alloy used in this work is given in the table below. The hot rolled sheet was cut into work pieces of dimensions 150x150x100mm by CNC EDM machine. The samples are polished using different grades of Si paper and disc polishing for uniform scratch less surface. Heat treatment of the sample was performed in a muffler furnace at a temperature 883*C for 4 hours. After heat treatment, water quenching of the sample was done for about 5-10 minutes. Table 1. Chemical composition. Al

90.794.7

3.84.9

1.21.8

0.30.9

(Max)0.1 (Max)0.5 (Max)0.5 (Max)0.15 (Max)0.25

Laser Shock Peening without Coating procedure. The LSP was conducted using generally Nd: YAG laser and the shock waves were generated. When the power density of the laser pulse is sufficiently high, then the shock waves are generated on the metal target. These shock waves propagate through the metal target and compressive residual stresses are being induced on the metal surface due to plastic deformation. During LSP, shock waves were induced using a Q switched repetition rate laser of 10Hz with a fundamental laser beam wavelength of 1064nm, pulse energy and pulse duration were 350mJ and 10ns respectively. In this process, the metal target surface is mirror polished and water is used as a confinement layer. LSPwC process is being carried on the decarburized surface which acts as an ablative surface. A smooth and uniform surface is created for multiple LSPwC. The thickness of the confinement layer (water) is kept 1-2mm by employing water jet setup. Characterization method. The residual stress measurements are performed using X- ray diffraction according to the sin2Ψ method using X’pert Pro system (PANalytical, Netherlands) at an operating voltage of 45 kV and current of 40 mA using CuKα-radiation with PRS X-ray detector. Scanning Electron Microscope (ZEISS EVO 18, Germany) is used to study surface morphology. The surface roughness profile (Martalk) is determined using surface profilometer (Stylus Method). The microhardness distribution of the sample was determined using a Vickers micro-hardness tester. A cross section of the specimen was prepared given by (ASTM: E384 standard) for hardness testing and hardness distribution was acquired under a constant load of 1.96N(200g). Atomic force microscope investigates surface attributes for both laser treated and untreated Al-2024 specimen by Nanosurf EasyScan2 (Switzerland) with constant static force operating type controlled by software version 3.1.0.22, firmware version 3.1.3.13, controller S/N 023-06-154 with head type EZ2-AFM and cantilever type ContAl-G. Results and Discussion Residual stress analysis. After LSPwC, high compressive residual stress is induced. Severe plastic deformation takes place due to shock waves generated which tends to increase the compressive residual stress. It was observed Al-2024 LSPwC treated specimen at surface stress has been increased to -126 MPa(maximum)

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Table 2. Compressive residual stress analysis. Specimen

Surface residual stress(MPa)

1. LSPwC

-126±16

2. Un-peened

71±3

Surface characteristics analysis. The surface morphology of the specimen was measured by scanning electron microscope. Both were investigated at 20μm scale bar, wide varieties of changes was seen.Variation in patterns were observed b/w un-peened and LSPwC. Grain size deformation took place after LSPwC which induces grain factors such as dislocation density and twinning boundary. Pores/ pits were observed in un-peened specimen. LSPwC treated specimen has showing decrement in number of pits/ pores due to compressive residual stress within surface and subsurface. Solidification patches was observed in laser treated specimen.

Fig. 1. SEM surface morphology image of un-peened and peened Al 2024 specimen Surface roughness analysis. Using profilometer by stylus method. The surface roughness was scrutinized for both LSPwC and unpeened Al-2024 specimens. The investigation states some amount of roughness has been escalated in LSPwC specimen compared to un-peened specimen. The increase in surface roughness is due multiple laser beam interactions which resulted in generation of shock waves which increases the dislocation density. The surface roughness (Ra) increased from 0.29 μm before treatment to 7.22 μm after LSP treatment.

Fig. 2. Roughness profile of un-peened Al-2024.

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Fig. 3. Roughness profile of LSPwC Al-2024. Atomic force microscopic analysis. Atomic force microscope (AFM) 3D topography of un-peened and LSPwC specimen is presented in fig. 4 respectively. It is evaluated that larger depths and areas are observed in LSPwC due to lower overlapping rate. Area roughness was detected in LSPwC treated region.

Fig. 4. AFM 3D topography of un-peened Al-2024.

Fig. 5. AFM 3D topography of LSPwC Al-2024.

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Micro-hardness analysis. The micro-hardness of the specimen(Al-2024) was measured using Vickers micro-hardness tester. The hardness of the specimen was obtained under a constant load of 1.96N(200g). It was observed that the micro-hardness of the metallic material increased from before treatment to after LSP treatment. The strength of the material Al-2024 greatly increased as a result of LSPwC. After LSP, plastic deformation of the specimen occurred resulting in an increase in the number of dislocation density and pinning of dislocation takes place. Thus, the micro-hardness of the material increased as result of high dislocation density and grain refinement. Summary. LSPwC can induce greater compressive residual stress thereby improvising the resistance offered for crack growth initiation. The surface roughness after laser treatment possesses visible changes within the surface and subsurface due to value increased to 7.22 μm after LSPwC. The micro-hardness has greatly increased in LSPwC specimen due to grain refinement and refined grain characteristics formation due to multiple shocks over surface and sub-surface. Grain refinement took place due to high pressure shocks within the surface and sub-surface which induces grain attributes thus ultimately enhances mechanical characteristics. References [1] Sathyajith, S., S. Kalainathan, and S. Swaroop. "Laser peening without coating on aluminum alloy Al-6061-T6 using low energy Nd: YAG laser." Optics & Laser Technology 45 (2013): 389-394. [2] Kalainathan, S., and S. Prabhakaran. "Recent development and future perspectives of low energy laser shock peening." Optics & Laser Technology 81 (2016): 137-144. [3] Prabhakaran, S., and S. Kalainathan. "Compound technology of manufacturing and multiple laser peening on microstructure and fatigue life of dual-phase spring steel." Materials Science and Engineering: A 674 (2016): 634-645. [4] Fu Zhao, William Z. Bernstein a “Environmental assessment of laser assisted manufacturing: case studies on laser shock peening and laser assisted turning” Journal of Cleaner Production 18 (2010) 1311e1319. [5] L. Zhang, J.Z. Lu, “Effects of different shocked paths on fatigue property of 7050-T7451 aluminium alloy during two-sided laser shock processing” Materials and Design 32 (2011) 480–486. [6] S. Baragetti, G. D Urso, “Aluminium 6060-T6 friction stir welded butt joints: fatigue resistance with different tools and feed rates” Journal of Mechanical Science and Technology 28 (3) (2014) 867~877. [7] Omar Hatamleh, Jed Lyons, “Laser and shot peening effects on fatigue crack growth in friction stir welded 7075-T7351 aluminium alloy joints” International Journal of Fatigue 29 (2007) 421–434. Cite the paper Yash Jain, Sandeep Varin, S. Prabhakaran, S. Kalainathan (2017). Effect of Multiple Laser Shock Peening without Coating on Al-2024-O Alloy for Automotive Applications. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.65.57.424

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Influence of Multiple Laser Shock Peening without Coating on Ti-6Al-4V Alloy for Aircraft Applications 62 Sandeep Varin1, Yash Jain1, S. Prabhakaran2, S. Kalainathan2 1 – School of Mechanical Engineering, VIT University, Vellore – 632 014, India 2 – Centre for Crystal Growth, VIT University, Vellore - 632 014, India DOI 10.2412/mmse.69.60.586 provided by Seo4U.link

Keywords: laser shock peening without coating (LSPwC), residual stress, hardness, roughness.

ABSTRACT. The current research proposes multiple laser shock peening without coating (LSPwC) process for aircraft titanium Ti-6Al-4V alloy using low energy Nd: YAG laser. The low energy of 350 mJ in at the fundamental wavelength 1064 nm is utilized for the laser surface modification process. The compressive residual stress measurements are accomplished according to X-ray diffraction sin2Ψ method. The surface morphology and surface roughness profiles were characterized using atomic force microscope and roughness profilometer respectively. The surface microstructure is examined by scanning electron and optical microscopes. Further, the mechanical properties of laser shock depth hardened layers were systematically analyzed through Vickers microhardness tester.

Introduction. Laser shock peening is a nonconventional surface modification technique. Laser peening uses impulsive pulse of high energy density that laser ablation induces shock waves which triggers compressive residual stress due to plastic deformation of material than conventional shot peening thus enhances the properties such as increase in hardness, roughness, prevent crack growth, increase in fatigue life, increase in corrosion resistance. Laser shock peening can be done by two ways low energy or high energy. This paper is completely followed low energy with focused beam by using a converging lens. Material was confined with aqueous (water) medium. Plasma pressure generation takes place as the beam strikes the surface hence, plasma has the tendency to not escape the water. Water acts as confinement layer [1 - 4]. Laser Shock Peening without Coating (LSPwC) generally implements laser (Nd: YAG) for generation of impulsive beam by the use of converging lens which has been projected on the surface of Ti-6Al- 4V. The surface with no ablative layer was confined by water medium. As the beam strikes the surface high temperature plasma generates which was confined by the aqueous medium and the portion of energy propagates as a shock wave in to the metal. Hence, once the plasma pressure exceeds the dynamic yield strength of the metal plastic deformation starts induces compressive residual stress [3, 4]. The generated compressive residual stress within the surface till certain depth concluded grain refinement and dislocations. Each spot produces a patch on the surface and the shape matches the output laser source. Due to repeated cycles-high strain/ stress rates produces that lead to significant microstructural changes [2, 5]. Titanium alloys have many applications in aircraft as it possesses high strength, low density, good corrosion resistance properties, and less weight. The coating of titanium powder metallurgy gives superior corrosion resistance paired with high strength and low density. Rapid/multiple laser shocks over surface of titanium promises greater depth of residual stress. Titanium has 2 phases alpha (hcp) and beta (bcp) which makes it heat treatable and weld-able. Presence of Alpha/Beta transformation in titanium assures a wide variety of microstructure and properties changes through surface © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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modification technique-Laser shock peening. The surface modification technique credits the manufacturer with the range of price and weight characteristics of components for both airframes and engines [1 - 6]. Experiments and Characterizations. Specimen preparation. Cold working was used during the laser shock peening technique on Ti-6Al4V rectangular piece of area (15x15x3) mm has been cut by the wire (Electrical Discharge Machine) EDM machine into 4 pieces. Microstructure has been observed by polishing the surface with grit surface range (600-2000) grains. Heat treatment took place in muffler furnace for 4-hours at temp 890° C. Leading by water quenching for 5-10 mins. Laser Shock Peening without Coating (LSPwC) process. Laser shock peening took place at ambient conditions. Generally, Nd: YAG laser terminates laser selection process as it possesses characteristics best suitable for the operation during experiment with wavelength 1064nm. The energy consumption by the laser was 350mJ with a gap of 10ns for each pulse. The cycle rate was constraint at 10 Hz but frequency increment can boost up the process by avoiding effects. Multiple and rapid shots over the surface has created a black colour patch (circumspect as laser peened region). The surface of material` was covered by a very thin layer of water (1-2 mm) which acts as confinement layer and has tendency to confine plasma. Overlapping rate of laser shots on the surface of titanium alloy Ti-6Al-4V was 75%. Characterization method. Residual stress measurements were done on laser peened and un-peened by Sin2 Ψ method using X’pert Pro system (PANalytical, Netherlands) at an operating voltage of 45 kV and current of 40 mA using Cu Kα-radiation with PRS X-ray detector. Roughness was measured from surface profilometer (MarTalk) by electronic stylus method. Micro-Hardness test was done by Vickers hardness tester using constant indentation load condition, Cross sectional mounting for micro-hardness was done as given by ASTM: E384 standard. Scanning Electron Microscope (ZEISS EVO 18, Germany) was used for measuring surface characteristics of both un-peened and laser peened region of Ti-6Al-4V. Atomic force microscope was used for measuring surface integrity of both un-peened and LSPwC treated specimen by Nanosurf EasyScan 2 (Switzerland) with static force operating mode controlled by software version 3.1.0.22, firmware version 3.1.3.13, controller S/N 023-06-154 with cantilever type-ContAl-G and head type-EZ2-AFM. Results and Discussions. Residual stress analysis. Compressive residual stress during LSPwC is due to thermal-mechanical behaviour at surface and subsurface grains. Multiple laser shocks on surface generates high shock wave results in severe plastic deformation which induces greater compressive residual stress. This analysis indicates that excessive shocks over surface would not escalates residual stress due to plastic deformation saturation of material [2-6, 7- 9]. Increase in compressive residual stress offers resistance to crack growth initiation. Compressive residual stress generated in laser treated specimen is much higher comparatively un-peened specimen of Ti-6Al- 4V, so was measured at surface is -176 MPa (Maximum). Un-peened specimen has tensile stress of 204.7 MPa within the surface. Scanning electron microscopic analysis. Surface characteristics were investigated by scanning electron microscope. Both the Ti-6Al-4V LSPwC and un-peened specimen were observed at scale bar of 10 μm. Analysing un-peened specimen shows micro-pores. Analysing laser peened specimen shows grain refinement on the surface which induces refined grain boundary, grain boundary dislocations features. Microstructure variation was easily identified in laser treated specimen [1, 6, 711].

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(a)

(b)

Fig. 1. (a) and (b) SEM surface morphology image of un-peened and LSPwC Ti-6Al-4V. Surface roughness analysis. Using Stylus method profilometer, Surface roughness has been observed. The Ra (arithmetic average of the all values of the profiles) has increased from 1.97 to 3.02 Îźm compared with un-peened surface. The irradiation of laser on surface increases surface roughness enhancing the mechanical property such as wear or friction for significant applications [1-3, 6, 10, 11]. . (a)

(b)

Fig. 2. Roughness mapping of (a) un-peened and (b) LSPwC Ti-6Al-4V. Atomic force microscopic analysis. Atomic Force Microscope was used to observe surface integrity of Ti-6Al- 4V in both LSPwC and un-peened specimen. Area roughness was observed and enhanced MMSE Journal. Open Access www.mmse.xyz

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due to various refined grain characteristics in LSPwC specimen. Twinning deformation was observed in LSPwC sample. Depth of laser treatment over surface can easily be identified.

(a)

(b)

Fig. 3. AFM images of (a) un-peened and (b) LSPwC Ti-6Al-4V. Micro-hardness investigation. Using Vickers micro-hardness test, Hardness of LSPwC and unpeened Ti-6Al-4V have measured at constant indentation load of 50 gf at every 50 μm depth. The average hardness value of treated Ti-6Al-4V compared with un-peened has been increased measured till 750 μm. Increase in dislocation density increases the hardness. Laser shock pressure impact decreases on depth leads to low plastic deformation within the surface hence, low dislocation [1,3,6,10-13].

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Fig. 4. Vickers micro-hardness profile of Ti-6Al-4V. Summary. LSPwC increased the compressive residual stress within the surface and sub-surface due to plastic deformation which enhances surface characteristics of material. Hence, it was observed in LSPwC surface the compressive residual stress increased to -176MPa (max.). This process has increased the hardness of the surface due to increase in grain density which induces grain boundary features within the surface when measured till 750 μm. The roughness for laser peened surface was observed and it has increased from 1.972 to 3.0231 μm. Microstructures changes were observed in SEM images. Variations in microstructure have been scrutinized. Grain refinement, dislocation density, twinning deformation was seen. These variations induce changes in mechanical properties within the laser peened region. References [1] Altenberger "On the effect of deep-rolling and laser-peening on the stress-controlled low-and high-cycle fatigue behavior of Ti–6Al–4V at elevated temperatures up to 550 C." International Journal of Fatigue 44 (2012): 292-302. [2] Kalainathan, S. "Recent development and future perspectives of low energy laser shock peening." Optics & Laser Technology 81 (2016): 137-144. [3] Prabhakaran, S. "Compound technology of manufacturing and multiple laser peening on microstructure and fatigue life of dual-phase spring steel." Materials Science and Engineering: A 674 (2016): 634-645. [4] Liucheng Zhou “Deforming TC6 titanium alloys at ultrahigh strain rates during multiple laser shock peening” Materials Science & Engineering A578(2013)181–186. [5] B.K. Panta “Studies towards development of laser peening technology for martensitic stainless steel and titanium alloys for steam turbine applications.” Materials Science & Engineering A587(2013)352–358. [6] Xiangfan Nie n “Experiment investigation of laser shock peening on TC6 titanium alloy to improve high cycle fatigue performance” Materials Science & Engineering A594(2014)161–167. [7] Weiju Jia “Effect of laser shock peening on the mechanical properties of a near-α titanium alloy” Materials Science & Engineering A606(2014)354–359 [8] Veronica Mara Cortez Alves de Oliveiraa “Short-term creep properties of Ti-6Al-4V alloy subjected to surface plasma carburizing process” J Mater Res Technology 2015; 4:359-66. [9] S. Prabhakaran “Warm laser shock peening without coating induced phase transformations and pinning effect on fatigue life of low-alloy steel” Materials and Design 107 (2016) 98–107. MMSE Journal. Open Access www.mmse.xyz

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[10] Mahfujur Rahmana, “Structural and tribological properties of the plasma nitride Ti-alloy biomaterials: Influence of the treatment temperature” Surface & Coatings Technology 201 (2007) 4865–4872. [11] Y.W. Fanga,“Effects of laser shock processing with different parameters and ways on residual stresses fields of a TC4 alloy blade” Materials Science & Engineering A 559 (2013) 683–692. [12] Ramkumar "Influence of laser peening on the tensile strength and impact toughness of dissimilar welds of Inconel 625 and UNS S32205." Materials Science and Engineering: A 676 (2016): 88-99. Cite the paper Sandeep Varin, Yash Jain, S. Prabhakaran, S. Kalainathan (2017). Influence of Multiple Laser Shock Peening without Coating on Ti-6Al-4V Alloy for Aircraft Applications. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.69.60.586

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Analytical Quality by Design – A Legitimate Paradigm for Pharmaceutical Analytical Method Development and Validation63 Balaji Jayagopal1, Murugesh Shivashankar1, a 1 – Department of Chemistry, School of Advanced Sciences, VIT University, Vellore-14, Tamil Nadu, India a – mshiavshankar@vit.ac.in DOI 10.2412/mmse.96.97.276 provided by Seo4U.link

Keywords: AQbD, CMA, CQA, DOE, CMM, QBD.

ABSTRACT. The apprehension and criticism on the quality and reliability of pharmaceutical products has augmented substantially, ensuing the regulatory bodies avowing the necessity of systematic principles for drug development. ICH instituted series of guidelines such as Q8, Q9, Q10 and Q11, all accentuating on implementation of systematic approaches of Quality by design (QBD) and Process Analytical Techniques (PAT). Quality by design has earned plentiful civility by formulation developers, the approach with sound scientific knowledge and early risk assessment is been accepted as an integral and imperative part of dosage form development, relishing the benefits of risk assessments on early stage and design space on the latter stage of product life cycle. However, the idea, reference, guidance and convention of practicing QBD in analytical discipline is limited, this article pronounces the ideologies and methodology of practising analytical QBD (AQBD) in analytical method development, dissolution test development and stability testing and validation design. The milestones of QBD such as Critical material attributes (CMA), Quality target product profile (QTPP), Critical quality attributes (CQA), Critical method parameters (CMP) and guidance for effective Design of experiments (DOE) differing from the conventional one factor at a time (OFAT) methodology are well explained. The software resources available for designing and interpretation of experiments, the statistical outcomes, its significance in establishing the control strategy and design space are well explained.

Introduction. The quality issue in pharmaceutical industries has become a very serious and domineering topic with China, Mexico, Canada and India rank in the first four places among the countries that received warning letters and import alerts from US FDA. Serious measures have been taken by pharma companies across world to put in more quality control measures in place. The manufacturing of pharmaceutical products used for achieving desired therapeutic aids for treatment of diverse ailments are considered as highly regulated since the past few decades. Poor manufacturing standards and their quality is being a worry for the industries and the regulatory agencies despite of the continuous contribution by the pharmaceutical industries in new drug discovery and innovations. The need for systematic approaches has been fingered mandatory both by the regulatory agencies and the manufactures. An article in, the wall street journal on September 2002 was an eye opener for the federal agencies on systematic approaches for drug manufacturing and quality control which compared the manufacturing standards of pharmaceutical industries with chips and laundry soap makers stated that the pharmaceutical industries are far behind in the quality aspects than the chips and soap makers [1]. The inevitable name “Juran”. Wherever there is a conversation on quality the name Juran is inevitable. Joseph M. Juran who have been called as the “father” of quality, a quality “guru” is a Romanian immigrant became the world well known expert in quality control has extended the philosophies of quality from the ancient conventional statistical practice to the todays so called quality management [2]. Juran is the man behind the quality of Japanese, suggests the need of managerial processes that focus on quality. The three managerial processes explained by Juran comprises of © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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quality planning, quality control and quality improvement, these three processes are combined called as Juran’s Triology [3]. The term Quality by design was first coined by Juran in his well-known publishing “Juran on Quality by design”. Juran supposed that quality could be strategic, and that most quality problems relate to the way in which quality was strategized [4,5]. Definition and Principle. QbD a systematic approach, begins with predefined aims, and smearing systematic understanding and risk managing approaches for drug development [6,7]. Quality by design is a methodical approach, braced by an extensive variety of statistical, economic, planning, psychological and other tools for risk assessment, establishing a design space, control strategy and recurrent improvement to upsurge method robustness, to close the quality gaps and shut down the hatchery of failures [5].

Fig. 1. AQBD lifecycle. Table 1. Conventional approach versus QBD approach. Parameter

Traditional

AQBD

Approach

Based on trial, error and understanding approach

Based on systematic approach

Performance

Performance is guaranteed by product testing and validation

Quality is constructed in the Robustness and reproducibility of the method built in method development stage

FDA submission

Including only data for submission

Submission with product knowledge and assuring by analytical target profile

Reliability

Method are based on batch trail and validation report.

Based on method performance to ATP criteria

Method

Method is frozen and discourages changes

Method flexibility with MODR and allowing continuous improvement

Targeted response

Focusing on reproducibility, ignoring variation

Focus on robust and cost effective method

Advantage

Limited and simple

Replacing the need of revalidation and minimizing OOT and OOS

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Benefits of implementing AQbD. Thorough understanding of attributes of the method. Enhanced knowledge sharing, development of high performance methods, dynamic control strategy leads to greater operative elasticity, efficient regulatory oversight, regulatory filing based on science and automatous rationale, saves significant resources as testing is only real-time, improved time to reach market, reduced consumer-generic scepticism, excellent returns on investment, limited product recalls and rejects, decreased post-approval changes. Regulatory prospective on QBD. The systemic approach to process and product design (QbD) concept was first accepted by FDA in 2004 and its view was published in ‘pharmaceutical cGMPs for 21st century – a risk based approach’[8]. In the same year FDA printed “Guidance for Industry PAT — A Framework for Innovative Pharmaceutical Development, Manufacturing, and Quality Assurance” in 2004. The outline is created on procedure thoughtful to facilitate novelty and riskbased regulatory inferences by manufacturer and the Agency [9]. Subsequent to that in 2005 FDA requested the New drug applicants were requested to submit chemistry manufacturing control (CMC) demonstrating Qbd.[10] The guidelines for QbD aspects were well explained by regulatory bodies through ICH guidelines such as Q8, Q9, Q10 explains about pharmaceutical development, quality risk assessment and pharmaceutical quality systems respectively explains the requirements and prospect of regulatory agencies on quality of product. AQbD and QbD. There are enough lights thrown on formulation development QBD point of view whereas either illustrations or guidance available for analytical QBD is very limited. The QBD philosophy in pharmaceutical formulation development emphasis on developing quality products with robust process techniques, the analytical QBD ensures robust analytical methods developed during product development and the unique quality of the product was ensured throughout the shelf life. Analytical QBD begins with predefined objectives. The elements of AQBD are Quality target method profile (QTMP), Identifying the critical method attributes (CMVs), affecting the Critical analytical attributes (CAAs) for accomplishing enhanced method performance such as robustness, ruggedness and leaving a scope for continual improvement within the design space. AQbd decreases the variability and enables to take timely decision and in turn taking control over the product information. This provides confidence on the product quality and facilitates the analysis of raw materials, finished products, stability samples, biological samples and to benefitted beyond the conventional ICH procedures. AQbD gets on board with Formulation QbD upon quality risk assessment studies like Basic risk management simplification methods (flowcharts, check sheets, Supporting statistical tools etc.), Failure Mode Effects Analysis (FMEA), Failure Mode, Effects and Criticality Analysis (FMECA), Hazard Analysis and Critical Control Points (HACCP), Preliminary Hazard Analysis (PHA), Hazard Operability Analysis (HAZOP), Fault Tree Analysis (FTA), Risk ranking and filtering and Design of Experiments (DOE) guided multi factor screening and design space design studies for ensuring the method performance [11,12,13]. Elements of QBD. Employment of AQbD rest on the target measurement which encompasses the product dossier in the form of ATP (analytical target profile, is the correspondent of QTPP in process design) and CQA (Critical quality attributes), followed by considerate on selection of suitable analytical technique, risk assessment for method and material variables, method scouting using DoE, generate method operable design space (MODS) and validation process for model, control strategy and continual improvement focussing the life cycle management [14,15]. Analytical target profile (ATP). ATP is the equivalent of QTPP in process design, it the foremost step in AQbD, it’s the goal setting process in the approach of developing the method. The ATP says about the set of attributes defining which moiety will be quantified, in which product, by what technique, over what concentration range along with the desired performance characteristics, The Specifications, acceptance limits should be connected to the proposed purpose of the analytical method [16]. Various aspects of methods with respect to HPLC/GC method such as phases selection, instrument requirement, sample characteristics, standard and sample preparation, procedural requirements such as sonication, centrifugation, mechanical shaking, diluent selection based on MMSE Journal. Open Access www.mmse.xyz

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solubility and pH of mobile phase/ diluent considering the pKa of the analyte shall be targeted based on the product and molecular known facts [17]. The literature survey performed as a primary task in conventional method development is also an integral part of ATP in AQbD. The method performance expectations such as precision, accuracy, range, detection limit, quantification limit, specificity, linearity, robustness, and ruggedness shall be assumed as predefined targets. A comprehensive knowledge of the envisioned purpose of the method must be developed from the understanding of moiety, its degradant, process impurities and the degradation pathways, sensitivity of drug to acid, base, oxidation, light, temperature, humidity and finally the critical quality attributes(CQAs)for the product [18]. Table 2. Formulation QbD Vs Analytical QBD [12]. Formulation Qbd/ FBD

Analytical QbD

Steps

Element

Objective

Element

Objective

Quality target profile (QTPP)

Define the type of drug delivery system, dosage form, dosage design, pharmacokinetics, stability expectations of formulation

Analytical Quality profile

Defines what to quantify and how to quantify.

Critical quality attributes (CQA)

Define the physical attributes, identification, Assay, Dissolution, Impurity profile requirements and other quality expectations

Critical quality attributes (CQA)

Separation, identification, accuracy, precision, robustness, ruggedness requirements

Critical process parameters (CPP)

Identifying the process parameters which could have impact on quality such as critical load level, agitation level, temperature, pH

Critical Method attributes (CMA)

Identifying method parameters which could have impact on the performance of the method, such as buffer pH, column temperature, injection volume, organic concentration etc.,

Critical Material attributes (CMC)

Evaluating the criticality type and grade of raw materials used in formulation

Critical Material attributes (CMC)

Evaluating the reagents, reagent grades and concentrations used in the analysis.

Design of Experiments (DOE)

Nested or factorial design to identify a centre process and create a design space

Design of Experiments (DOE)

Nested or factorial design identify a centre method and create a method design space

Process validation

Establishing practical proof that a process is reliably bringing quality products

Method validation

Establishing practical proof that the method is reliably bringing quality results

Control Strategy

Ensuring the product production with desired quality

Control Strategy

Ensuring the method performance with accepted results

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Table 3. ATP for API and Finished dosage forms [15]. ATP elements

Target

Justification

Target sample

Active ingredient or Finished drug product

Developing a analytical method to for quantification of certain molecule in Active ingredient/FP it can be the active moiety or any other contents

Method type

Reverse phase or Normal phase

Based on the molecule polarity the type of method shall be targeted

Instrument requirement

HPLC, GC, Potentiometer

Based on the availability of chromophores, volatility and other structural and molecular nature of the moiety the method shall be explained.

Sample characteristics

Solid, Liquid, Powder for oral suspension, suppositiories, extended release tablets

The sample extraction technique shall be targeted, the necessity of sonicator, mechanical shaker, centrifuge, filters could be defined.

Standard and Preparation

Diluent

Justified based on the solubility and pKa of the drug

Assay of APPI/FP/In process samples

The profiling begins with target of developing common method quantifying API, FP, In-process analysis, Stability samples, Uniformity of dosage unit’s analysis.

sample

Method application

Critical Quality attributes. A chemical, biological, physical, microbiological properties that must be inside a proper limit or dispersal to ensure the desired product excellence [19]. In case of process related CQA the drug products quality traits such as assay, Dissolution, chromatographic purity, uniformity of dosage units, residual solvents, water content, microbial limits, viscosity in case of creams, suspensions, emulsions and medicament in soft gelatin capsules are considered as critical quality traits. Whereas in case of AQbB considering a HPLC method development as typical example, tailing of peak, Theoretical plate count, resolution between impurities and between impurities and main analyte, peak purity, capacity factor, LOQ and LOD achievement shall be considered as critical quality attributes. In case of dissolution method development, the sink condition requirements based on the solubility of drug, developing a method without cone formation, cross linking of gelatin which retards the release of upon storage of hard gelatin and soft gelatin capsules shall be considered as CQA, In pharma R & D’s which work on generic market, the development of dissolution media to compare the dissolution profile with that of the reference listed drugs the profile comparison the mathematical approach such as F1 or similarity factor and F2 or dissimilarity shall be considered as CQA[20]. Identify a CQA based on the extreme of harm to patient safety and efficacy as a result of analytical result falsification. Identify a CQA before considering risk control and don’t change because of risk management. Primary method scouting. With the CQA goals defined, method scouting can begin, classically with the literature survey, physical and chemical properties of the moiety, flowcharts and decision trees to guide the analyst to begin with among the choices. Automation in scouting experiments is ideal procedure. For example, a well-organized and complete experimental plan based on methodical, scouting of three crucial components of a reversed phase HPLC method (column, pH and organic modifier) shall be chosen and finalised [21]. The product of the method scouting will be a basic method which satisfies all the ATPs defined prior for the method. Risk Assessment. Risk assessment is generally understood that hazard is well-defined as the mixture of the possibility of occurrence of harm and the severity of it [22]. In aid of explaining risk assessment three questions are often helpful. 1. What could go wrong? MMSE Journal. Open Access www.mmse.xyz

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2. What is the probability it may go wrong? 3. What are the severities? Some of the well-recognised risk assessment tools in AQbD are FMEA, Ishikawa cause and effect analysis or Fish bone diagram and prioritization method [23]. FMEA assessment could be performed using a simple spread sheet where the failure type, impact, severity, causes and corrective action with measures could be assessed. An FMEA uses few measures to assess a failure: 1) the severity on analytical result, 2) frequency and 3) Ease of detection. Evaluator must set on a rating between 1 and 10 (1 = low, 10 = high) for the severity, occurrence and detection level for each of the failure modes. After rating the a risk priority number (RPN) could be calculated. RPN shall be calculated by: RPN = severity x occurrence x detection One of the most communal choice to achieve a structured risk assessment is to custom a Ishikawa fishbone diagram or cause-and-effect diagram to recognize possible aspects that may affect the method performance. Fishbone diagrams classes risks in to those related to material, methods, measurements, instrumentation and other factors [24]. Table 4 (a). Typical FMEA for a RP HPLC assay method. Method

Failure Type

Potential Impact

SEV

Potential Causes

OCC

Detection Mode

Outline method procedure, step or product being analyzed

Define could go incorrect (based on the Critical method parameter and Critical material attributes assessment)

evaluate the impact on the crucial output variables.

Evalute the severity to the result?

What reasons the key input to go incorrect?

Frequency of occurence

Existing control prevent failure

Assay method to quantify the content of API in the drug product by RP HPLC method

Placebo peak and analyte peak merged

Resolution between placebo peak and main analyte will reduce

Assay method to quantify the content of API in the drug product by RP HPLC method

Bad peak shape with tailing.

(1 = low, 10 = high)

DET

RPN

Ease of Detectability

Risk priorit y numbe r

(1 = low, 10 = high)

baseline hump at retention time of main peak will be observed

(SEV x OCC x DET) pH of buffer (Critical method attribute)

Grade of reagent eg., ammonium acetate used for mobile phase

pH mentioned in the procedure 5

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Reagent grade mentioned in the procedure

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Table 4 (b). Typical FMEA for a RP HPLC assay method. Recommended Actions

Responsibil ity

Target Date

Action Taken

SEV

OCC

DET

Actions taken or to be taken for decreasing the occurrence of the cause or facilitating the detection?

Person responsible for the recommend ed action?

Target date executing the recommended action?

Actual actions implemented.

How severe is the effect to the result?

How frequently is this likely to occur?

How easy is it to detect?

(1 = low, 10 = high)

perform DOE considering pH as critical method attribute and create a design space.

Analyst

perform DOE considering different reagent grades as critical material attribute and create a design space.

Analyst

10 days

pH range clearly defined in procedure

set of suitable reagent grades identified and clearly mentioned in the procedure

RPN Risk priority number

(1 = low, 10 = high)

(SEV x OCC x DET)

Fig. 2. Ishikawa diagram showing the cause and effect analysis for a Related substances method by RP HPLC method. Critical material attributes and Critical method attributes. A material or method attribute is critical when a genuine change in that parameter can pointedly influence the quality of the output. Identifying the critical materials such as chromatographic columns, reagents, solvent, material grade and critical method attributes like pH of the mobile phase, column temperature, concentration of organic modifier are part of risk assessment process. Understand and control the variability of the material and method attributes to meet the Analytical target profile by mapping the material and method variables to CQAâ&#x20AC;&#x2122;s.

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Fig. 3. Understand and control the variability of the material and method attributes to meet the Analytical target profile. Design of experiments. The tertiary class of risks recognized from the Fishbone Analysis or FMEA or other risk assessment analysis contains instrumental parameters, method variables, material variables those can be itemized and explored with help of Design of Experiments approach (DoE). It can be determined with one variable at time design or multi variables designs and their relations and responses. Multifactorial design provides a chance to screen number of conditions in minimum experiments, then the critical method variables were identified with aid of statistical data and the method operable design space [25]. There are many sorts of DOE design tools and principles stated. Full factorial design for two or three factors study for small studies. A D-optimal type custom DOE design for factors more than 3, when the design space is constrained and the method space contains variables that are not feasible or are impossible to run [26]. Fractional factorial design or Taguchi methods, to achieve reduced variation, prioritizes criticality of variables from high to low [27,28]. Plackett-Burman method (screening few critical factors from large group of variables). Pseudo-Monte Carlo Sampling (pseudorandom sampling) method, use random number generation algorithm [11,29]. Establishment of design space. Method operable design region (MODR) is the multidimensional space establishment based on outcome of the results of DOE upon statistical computation. A change in method within the MODR can provide suitable method performance meeting the ATP. Usually the centre point method of the design space will be finalised and will be validated, further the changes within the established design space is not considered as a change and revalidation with respect to that change is redundant. Control Strategy. In product AQbD, control strategy is designed to ensure the instant method performance meeting the required ATP. Control strategy is consequent from various data collected during method development phase, statistical data obtained during DoE, MODR, robustness studies, forced degradation studies, stability studies, compatibility studies and method verification process. The capability of the methodology to meet the ATP is well predicted with aid of the above-mentioned data. The control strategy need not be different from the conventional procedure it can be as simple as providing caution notes on the standard testing procedures such as precaution comments like usage of particular grade of reagents, method sensitivity with respect to pH, organic ratio in mobile phase [30]. Continuous Method Monitoring. CMM is the final stage of AQbD. Life cycle management if done by monitoring the method performance over a period to guarantee that the pre-defined ATP is met. Monitoring can be done by using control charts to keep a track on the method performance parameters. This continuous monitoring enables the scientist to proactively identify any out of trend, out of specification results. References [1] Abboud, L., & Hensley, S. (2003). New prescription for drug makers: Update the plants. The Wall Street Journal. 3-9. MMSE Journal. Open Access www.mmse.xyz

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[2] Juran, J.M. (2002). Product Inspection Guides. Retrieved from Skymark website: http://www.skymark.com/resources/leaders/juran.asp [3] Juran, J., & Blanton, A. G. (1999). Juran’s Quality Handbook. NY: McGraw Hill. [4] Juran, J.M. (1992). Juran on Quality by Design: The New Steps for Planning Quality into Goods and Services. NY: The Free Press. [5] Early, J. F. (2013, February 14). Quality by Design, Part 1. Quality Digest. Retrieved from Qualitydigest website: http://www.qualitydigest.com/inside/quality-insider-article/quality-designpart-1.html [6] Bhupinder, S.B. (2014). Quality by Design (QbD) for Holistic Pharma Excellence and Regulatory Compliance. Pharma Times, 46(08), 26-33. [7] Department of Health and Human Services USFDA. (2007). Pharmaceutical Quality for the 21st century A risk-based approach progress report. Retrieved from FDA website: http://www.fda.gov/AboutFDA/CentersOffices/OfficeofMedicalProductsandTobacco/CDER/ucm12 8080.htm [8] Vogt, F.G., & Kord, A.S. (2011). Development of Quality-By-Design Analytical methods. Journal of Pharmaceutical sciences, 100(3), 797-812. [9] Department of Health and Human Services USFDA. (2004). Pharmaceutical CGMPs for the 21st century - A risk-based approach Final report. Retrieved from FDA website: http://www.fda.gov/downloads/drugs/developmentapprovalprocess/manufacturing/questionsandans wersoncurrentgoodmanufacturingpracticescgmpfordrugs/ucm176374.pdf [10] Department of Health and Human Services USFDA, CDER, CVM, ORA. (2004). Guidance for Industry PAT — A Framework for Innovative Pharmaceutical Development, Manufacturing, and Quality Assurance. Retrieved from FDA website: http://www.fda.gov/downloads/Drugs/Guidances/ucm070305.pdf [11] Sangshetti, J.N., Deshpande, M., Zaheer, Z., Shinde, D.B., & Arote, R. (2014). Quality by design approach: Regulatory need. Arabian Journal of Chemistry. Retrieved from sciencedirect website: http://www.sciencedirect.com/science/article/pii/S1878535214000288 [12] Peraman, R., Bhadraya, K., & Yiragamreddy, P.R. (2015). Analytical Quality by Design: A Tool for Regulatory Flexibility and Robust Analytics. International Journal of Analytical Chemistry, 2015. Retrieved from hindawi website: https://www.hindawi.com/journals/ijac/2015/868727/ [13] ASME. B89.7.3.1-2001. (2001). Guidelines for decision rules: considering measurement uncertainty in determining conformance to specifications. [14] Eurachem. (2007). Use of uncertainty information in compliance assessment. Retrieved from eurachem website: https://www.eurachem.org/index.php/publications/guides/uncertcompliance [15] Beg, S., Sharma, G., Katare, O.P., Lohan, S., & Singh, B. (2015). Development and Validation of a Stability-Indicating Liquid Chromatographic Method for Estimating Olmesartan Medoxomil Using Quality by Design. Journal of Chromatographic Science, 53(7), 1048-1059. [16] Rozet, E., Lebrun, P., Michiels, J.F., Sondag, P., Scherder, T., & Boulanger, B. (2015). Analytical Procedure Validation and the Quality by Design Paradigm. Journal of Pharmaceutical statistics, 25(2), 260-268. [17] Karmar, S., Garber, R., Genchanok, Y., George, S., Yang, X., & Hammond, R. (2011). Quality by Design (QbD) based development of a Stability Indicating HPLC Method for Drug and Impurities. Journal of chromatographic science. 49(6), 439-446.

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[18] Karmarkar, S., Miller, R., Yang, X., & Garber, R. (2009). Design of Forced Degradation Experiments to Demonstrate Specificity of Stability Indicating Methods for Pharmaceutical Injection Products. Presented at the LC-GC Pham Sep Conference. Philadelphia, PA. [19] International Conference on Harmonisation (ICH) Tripartite Guideline. (August 2009). ICH Q8(R2). [20] Gohel, M.C., Sarvaiya, K.G., Shah, A.R., & Brahmbhatt, B.K. (2009). Mathematical Approach for the Assessment of Similarity Factor using a New scheme for Calculating Weight. Indian Journal of Pharmaceutical Sciences, 71(2), 142-144. [21] Li, Y., Terfloth, G.J., & Kord, A.S. (2009). A Systematic approach to RP-HPLC method development in a pharmaceutical QbD environment. Americal Pharmaceutical review, 12, 87-95. [22] International Conference on Harmonisation (ICH) Tripartite Guideline. (November 2005). ICH Q9. [23] Kumamoto, H., & Henley, E. (1996). Probabilistic risk assessment and management for engineers and scientists. (2nd ed.). Piscataway, NJ: IEEE Press. [24] Ishikawa, K. (1985). What is total quality control? The Japanese way. Englewood Cliffs, NJ: Prentice-Hall, pp 63–64. [25] Raman, N.V.V.S.S., Mallu, U.R., & Bapatu, H.R. (2015). Analytical Quality by Design Approach to Test Method Development and Validation in Drug Substance Manufacturing. Journal of Chemistry, 2015. http://dx.doi.org/10.1155/2015/435129 [26] Thomas, A.L. (2014). Design of Experiments for Analytical Method Development and Validation. BioPharm International, 27(3). Retrieved from Biopharm International website: http://www.biopharminternational.com/design-experiments-analytical-method-development-andvalidation [27] Roy, R. K. (2001). Design of Experiments Using the Taguchi Approach : 16 Steps to Product and Process Improvement. Bk&Cd-Rom edition. John Wiley & Sons. [28] Giunta, A. A., Wojtkiewicz, S.F., & Eldred, S. M. Overview of modern Design of experiments for computational simulations. American Institute of Aeronautics and Astronautics. Retrieved from research gate website: https://www.researchgate.net/publication/216756600_Overview_of_modern_design_of_experiment s_methods_for_computational_simulations [29] Control Strategy Case Studies. Retrieved from ICH website: http://www.ich.org/fileadmin/Public Web Site/Training/GCG - Endorsed Training Events/APEC LSIF JCCT workshop Beijing China Dec 08/Day 2/Control Strategy Case Studies.pdf. [30] Drug product and delivery, SSCI, Crystallization Expert. (2014). Retrieved from ssci-inc website:http://www.ssciinc.com/DrugSubstance/PATandPharmaceuticalQualityByDesign/tabid/86/ Default.aspx. Cite the paper Balaji Jayagopal, Murugesh Shivashankar (2017). Analytical Quality by Design – A Legitimate Paradigm for Pharmaceutical Analytical Method Development and Validation. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.96.97.276

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Effect of Laser Shock Peening Without Coating on Surface Morphology and Mechanical Properties of Nickel-20064 Aniket Kulkarni1, Siddarth Chettri1, S. Prabhakaran1, S. Kalainathan1,a 1 – Laser Materials Processing Laboratory, Centre for Crystal Growth, VIT University, Vellore - 632 014, India a – kalainathan@yahoo.com DOI 10.2412/mmse.55.5.304 provided by Seo4U.link

Keywords: Nickel-200 specimen, X-Ray diffraction, AFM, peening process.

ABSTRACT. This paper delineates the after effects of low energy Laser shock peening without coating on Nickel-200 specimen. Comparative study of X-Ray Diffraction analysis of the treated specimen with untreated specimen suggests the presence of compressive residual stress and grain refinement. The residual stress analysis was carried out using the sin2 Ψ method of X-ray Diffraction. The results of which indicate compressive residual stress values have increased. The AFM results tell us that there is a considerable increase in the surface roughness after the laser peening process. There is a grain refinement which is also supported by AFM, XRD data. The hardness profile of the material was increased by a substantial amount. The crystalline size and the micro-strain have been calculated for peened and unpeened samples using the Scherrer’s equation from the X-ray diffraction data.

Introduction. Surface is the outermost layer of the material which is in contact with other materials hence, it is essential for us to know the properties of the surface and upgrade them for streamlining of the mechanical properties of the surface to guarantee the long life of the materials. It is highly important to know about the surface because most of the cracks are generated on the surface of the material and then propagate within the material thus giving birth to fatigue. Where ever may the material be used, fatigue weakens the material thus ultimately leading to failure of the material [1]. Laser processing of materials in liquid media has been gaining importance in recent years. The effects of laser shock peening on the material have been extensively studied by Sano et al [2]. Laser shock Peening (LSP) has been extensively examined for its signiﬁcant increment in both the fatigue strength and the life time of metal, which along these lines takes care of the issue of high cycle fatigue (HCF) breaking of aircraft engines, by creating an substantial residual compressive stress on the surface of metal through the action of a laser shock peening. The residual compressive stress generated due to Laser shock peening process can have a large impact on coating mechanical properties and durability. Compressive residual stresses at the surface hinder the development of surface-started cracks to which enormously increases the life-time of the material. The likelihood of producing residual tensile stress on the overhead of surface of the sample is a major disadvantage of the laser shock peening without coating technique which is because of the higher sweltering effect, the surface dissolving and resolidification occur a couple of microns on the metal surface [3]. The fundamental principle behind laser shock peening with material in water confinement can be clarified as takes after. At the point when a laser pulse is focused around a target material which is submerged in water, the material surface layer vaporizes immediately [1]. The energy of the laser pulse is constantly taken by the water vapour for the entire pulse duration. This procedure changes over the vapour to high temperature plasma. The water layer keeps the profoundly extending plasma towards the material surface which in turn incites an exceptional shock wave of high pressure [3, 4]. © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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Experiments and methods. Laser shock peening without coating (LSPwC). A specimen of dimensions 4cm × 2cm × 2mm were prepared by cutting a 30 mm thick Nickel -200 sheet by Electric Discharge Machining (EDM) wire cutting. The mechanical properties of the base material is given in table 1. The specimen was highly polished to mirror finish before treating the specimen with LSPwC technique. The process of LSPwC was carried out using a Q-Switched Nd:YAG laser operating with a fundamental wavelength of 1064nm was used as a laser source. The parameters for LSPwC process is provided in table 2. The full width at half maximum (FHWM) was 10 ns with a repetition rate of 10 Hz, which was carried to the target material by using a dichroic mirror and a Plano convex lens of focal length 300mm. A confinement layer is produced on the surface of the sample by a layer of water on work piece by water jet arrangement. The lens is protected from the water spilling during the time of peening by an electric drier which is placed near the lens. The specimen is fixed in a holder which is computer controlled, making the specimen move in the X and Y direction during the irradiation of the laser pulse. The laser pulse density (Np) of the laser can be controlled by controlling the velocity of the transitional stage. The pulse density was kept constant in this experiment [1]. Table 1. Laser shock peening without coating parameters. Pulse

Pulse

Repetition

Power

Pulse

Spot

Energy

duration

rate

density

diameter

350 mJ

10 ns

10 Hz

6.96 GWcm-2

800 pulses cm-2 0.8 mm

Characterization procedure. The sample is subjected to X-ray diffraction (XRD). Crystallographic analysis was carried out using Scherrer’s formula:

T

K  cos 

(1)

where T is crystallite size,  is the wavelength of X-ray,  is the Full width half maxima and  is the glancing angle [5]. One needs to set up an exceptionally close surface of the cross-sectional thin thwart so as to comprehend the genuine changes created by LSP. The depth wise compressive stress estimations are taken as indicated by the X-beam diffraction sin2 Ψ technique. The X-ray beam of 4 mm2 at the diffractive edge of 44° is measured by X′pert Pro framework (PAN alytical, Netherlands) [6] at a working voltage of 45 kV and current of 40 mA utilizing Cu Kα-radiation with PRS X-beam locator. The electrolyte polishing progressive layer removal procedure is received for depth examination of compressive residual stress. It is proceeded by applying 80% methanol and 20% perchloric acid solution by controlling the voltage (18V) with steady electro polishing time duration. The surface roughness profile measured utilizing surface profilometer [1] (MarTalk). According to ASTM: E384 standard, the transverse cross-sectional examples are utilized to quantify Vickers micro hardness estimations with a steady load of (50gf) was applied for 10 sec duration. The chemical composition of the Nickel 200 is given in table no. 3.

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Table 3. Chemical composition of Nickel-200. Alloy

Max

0.15

0.35

0.01

0.35

0.25

0.40

99.0

Results and Discussions XRD analysis. The presence of major peak at 44° of 2θ angle indicates the existence of retained austenite in both the peened and unpeened sample [5, 7]. There is also a shift in the peak in the treated sample, indicating that the LSPwC treatment results in the induced lattice strain. The crystallite size was calculated using Scherrer’s formula and is found to be reduced significantly after the LSPwC treatment, hence indicating grain refinement.

(a)

(b)

Fig. 1. XRD analysis of unpeened and laser shock peened nickel 200 specimens. (a) Indexed graph (b) Magnified image. AFM analysis and surface roughness. The topographical analysis of the sample that underwent LSPwC was done using Atomic Force Microscope (AFM). Sampling area of 2µm × 2µm and sampling length was set as 0.5mm for the measurements. Owning to deterioration of the surface quality most of the structural component failure starts at the surface. The surface integrity of treated sample and as well as the untreated sample was evaluated as surface roughness and surface topography. The surface topography of the sample surfaces is shown in the figure (Fig.2). From the above figure it can be observed that after LSPwC, the valleys are more in unpeened sample. The laser shot indentation is the main reason for the suppression of peak to valley. Thus from AFM surface topography [1] it can be seen that the laser peened sample surface shows more surface roughness than unpeened sample surface. Laser Peening without Coating prompts higher surface roughness contrast with conventional laser peening[9].

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(a)

(b) Fig. 2. AFM Surface morphologies of (a) unpeened and (b) laser shock peened nickel 200 specimens. Residual stress analysis. The Residual stress measurement of the peened and unpeened sample was investigated by X-ray diffraction sin2ѱ method, where ‘ѱ’ is the angle between the normal to the surface and the normal to the diffraction plane. The residual stress was measured in the sigma-x direction. It was observed that the laser peened surface showed higher compressive residual stress compared to that of the unpeened surface [1]. The initial value of the residual stress is due to the manufacturing process and thus residual stress was induced in the sample [8]. The residual stress at the surface as well as at depth of 50 microns has increased by a substantially large amount which is reflected in table 3.

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Table 3. Residual Stress data. Nickel 200

Surface (MPa)

50 Microns (MPa)

Unpeened

-32.6

-17.6

Peened

-323.4

-436.0

Table4. Residual stress measurement parameters. Characteristic X ray

CuKα

X ray tube Voltage

20KV

X ray tube Current

5mA

Diffractive plate

222

Diffraction angle 2θ

76°

X ray irradiated area 2 mm X ray detector

PSSD

Micro-hardness analysis.

Fig. 4. The Vickers microhardness profile for unpeened and LSPwC nickel specimens. The micro-hardness test was carried out using Vickers-micro-hardness tester for both the peened and the unpeened sample and their results were compared and it wa s observed that the laser peened sample showed an increased in the micro -hardness value of compared to that of unpeened sample value. Fig.4 indicates clearly that there is improvement in the hardness values till a depth of 900 microns [10]. Summary. Laser peening without coating studies on Nickel 200 showed an improvement in the surface stress from -32.6 MPa to a maximum of -323.4 MPa. The micro hardness test confirmed that the LSPwC process resulted in work hardening as well as the increase in the depth of hardened layer. Increase in the surface roughness was reported after the laser peening process the surface roughness analysis reported an increase in the surface roughness MMSE Journal. Open Access www.mmse.xyz

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after laser peening indicating an increase in the corrosion resistance of the mater ial. More confirmation study is required to identify the improvement in fatigue and wear resistance. Low energy Nd:YAG laser is feasible to perform Laser Shot Peening.When using low energy laser, peening without sacrificial coating is more beneficial to induce higher magnitude compressive stress. Depending on the material properties the higher surface roughness may cause deterioration in corrosion resistance, this can be investigated further. Acknowledgments. The authors would like to thank IIT Bombay for providing equipment for Residual Stress analysis and VIT for providing the facilities and constant support, and also would like show our gratitude to our guide Prof.S.Kalainathan, for providing us with the opportunity to carry out this project. References [1] S. Sathyajith,S.Kalainathan, S.Swaroop “Surface modification of 17 -4 PH stainless steel by laser peening without protective coating process” Surface & Coatings Technology 278, 2015, 138–145. [2] Yuji SANO, Koichi AKITA, Kiyotaka MASAKI, Yasuo OCHI Igor ALTENBERGER and Berthold SCHOLTES “Laser Peening without Coating as a Surface Enhancement Technology” JLMN-Journal of Laser Micro/Nanoengineering Vol. 1 (3), 2006. [3] S. Kalainathan, S.Prabhakaran “Recent development and future perspectives of low energy laser shock peening” Optics & Laser Technology 81(2016), 137 –144. [4] S. Prabhakaran, S. Kalainathan “Warm laser shock peening without coating induced phase transformations and pinning effect on fatigue life of low -alloy steel” Materials and Design 107 (2016) 98–107. [5] Xizhang Chen, JingjunWang, YuanyuanFang, BruceMadigan, GuifangXu, Jianzhong Zhou “Investigation of microstructures and residual stresses in laser peened Incoloy 800H weldments” Optics & Laser Technology 57, 2014, 159–164. [6] Majumdar, Jyotsna Dutta, Evgeny L. Gurevich, Renu Kumari, and Andreas Ostendorf. "Investigation on femto-second laser irradiation assisted shock peening of medium carbon (0.4% C) steel." Applied Surface Science 364,2016, 133-140. [7] P.Mukherjee, A.Sarkar, P.Barat, T.Jayakumar,S. ahadevan and Sanjay K. Rai “Lattice Misfit Measurement in Inconel 625 by X-Ray Diffraction Technique”. 2006 [8] S. Sathyajith, S. Kalainathan “Effect of laser shot peening on precipitation hardened aluminum alloy 6061-T6 using low energy laser” Optics and Lasers in Engineering 50, 2012, 345–348 [9] Gill, Amrinder S., Abhishek Telang, and Vijay K. Vasudevan. "Characteristics of surface layers formed on inconel 718 by laser shock peening with and without a protective coating." Journal of Materials Processing Technology 225, 2015, 463-472. [10] Li, Yinghong, Liucheng Zhou, Weifeng He, Guangyu He, Xuede Wang, Xiangfan Nie, Bo Wang, Sihai Luo, and Yuqin Li. "The strengthening mechanism of a nickel-based allo y after laser shock processing at high temperatures." Science and Technology of Advanced Materials 2016. Cite the paper Aniket Kulkarni, Siddarth Chettri, S. Prabhakaran, S. Kalainathan, S. Kalainathan (2017). Effect of Laser Shock Peening Without Coating on Surface Morphology and Mechanical Properties of Nickel200. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.55.5.304

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Characterization of Cr Doped CuGaS2 Thin Films Synthesized By Chemical Spray Pyrolysis N. Ahsan1,a, S. Kalainathan1,2, N. Miyashita1, T. Hoshii3, Y. Okada1 1 – Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Japan 2 – Centre for Crystal Growth, VIT University, Vellore, India 3 – School of Engineering, Tokyo Institute of Technology, Tokyo, Japan a – ahsan@mbe.rcast.u-tokyo.ac.jp DOI 10.2412/mmse.53.55.304 provided by Seo4U.link

Keywords: density functional theory, thin films, intermediate band solar cells, spray pyrolysis, CuGaS2.

ABSTRACT. Addition of an impurity or intermediate band in a semiconductor can extend its optical functionalities to novel application such as intermediate band solar cells (BSCs). For this purpose, the optical and electronic characterization were performed on Chromium (Cr) doped (1-4%) chalcopyrite CuGaS2 (CGS) thin films synthesized by chemical spray pyrolysis technique on glass substrates. The structural and chemical characterization studied in the past confirmed that the prepared films are in tetragonal chalcopyrite structure with polycrystalline nature [1]. In the present study, electronic transitions studied by photo-modulated reflectance (PR) measurements showed widened bandgaps when Cr was added, and agrees well with our calculation based on density functional theory (DFT). Native defect-related transitions typically observed within the bandgap of the host CGS semiconductor were reduced in the Cr added films. This observation is consistent with photo-luminescence (PL) spectra measured at room temperature. An additional signature of an impurity band emerged in the PR transitions for Cr-added samples. Analysis of spin-resolved density of state calculation suggests that the IB originates from spin-polarized bands.

Introduction. Addition of an intermediate band (IB) such as an impurity band can extend the functional limit posed by the conventional two-band character of semiconductor materials. For example, the concept of intermediate band solar cells (IBSC) makes use of an intermediate step to excite electrons from the valence band (VB) to the conduction band (CB) by two-step photon absorption (TSPA) of long wave-length photons that otherwise transpire through the material [2]. Detailed balance calculation predicts conversion efficiency of 65.1% for a three band solar cell (e.g. VB, IB, CB) under maximal solar concentration which is much higher than the conventional solar cell consisting two bands (e.g. VB and CB) [3]. The key operational demonstration of TSPA both at low [4] and room temperature [5-7] has been presented in a few IB systems of thin films and nanostructures despite much enhancement is needed in the magnitude of the TSPA driven current for practical application. The quest for three band system have been spanned over various IB materials in recent years such as thin films of highly mismatched alloy (HMA) III-V dilute nitrides and II-VI oxides [5,8-10], deep impurity doped hosts [6], and nanostructures using quantum dots [11], quantum rings [12], etc. Key factors that drive IB formation process are different in each approach, and consist of host electronic structures, structural dimensionality, nature of the impurity atoms, etc. In HMA thin films, isoelectric impurities atoms with much different affinity and size in III-V and II-VI hosts modifies electronic structures remarkably with distinct three band features [13-15]. Low-dimensional structures such as QD array produce distinct mini-bands due to quantum-size effect [2]. Fabrication of large number in density and stacks of QD array can promote the needed optical absorption for IR-generated currents. In order to improve the IBSC efficiency, host materials with much wider band gap such as AlGaAs or InGaP are required [16]. MMSE Journal. Open Access www.mmse.xyz

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For solar cells, Cu-based chalcopyrite semiconductors attract research interests mainly due to their higher absorption coefficients suitable for thin-film application. Of particular, the direct bandgap of CuGaS2 or ‘CGS’ in short lies in the green region of the visible spectrum at room temperature [17]. It can be a suitable IB host since its bandgap of 2.4eV is relatively wide, and can accommodate impurity or IB bands sufficiently deep to avoid thermal escape of photo-generated carriers staying at the IB bands. Doping of transition metals in CGS has been predicted to be a potential candidate for IB solar cells [18]. Earlier reports for doping of transition metals such as Fe [19], V [20], Mn [21], Cr [22], Zn, Ti [23] to the CGS hosts have been predicted for the creation of IB. The valency match and the less distortion in lattice make the transition and rare earth elements to a suitable dopant for a chalcopyrite lattice. Recently, we have reported that chemical spray pyrolysis deposition technique can be employed fabricating Cr doped CGS thin films on glass substrates maintaining polycrystalline qualities [1]. The addition of chromium didn’t produce any observable lattice changes in X-ray diffraction, presumably due to similar ionic radii and electron affinity. The pyrolysis technique is employed to extend its application to cost effective large scale production. In this paper, at first, we study the optical properties using photo-modulated reflectance (PR) and photoluminescence (PL) characterizations at room temperature. Next, electronic band structure and density of state analysis are performed based on density functional theory (DFT). Sub-bandgap transitions in PR and modification in PL in Cr added CGS thin films have been discussed in terms of the calculation. Experimental. Thin films were synthesized by chemical spray pyrolysis technique on glass substrates. The precursor solution for the host CGS synthesis consists 0.1 M of copper acetate, gallium chloride and of thiourea dissolved in deionised water. For Cr doping, the molar concentration of chromium chloride was varied between (1-4 wt%). The follow-on mixture solution was deposited on glass substrates by the chemical spray pyrolysis technique. Temperature of the glass substrates was maintained at 250 ºC. Obtained thin film were single phase as confirmed by X-ray diffraction, and presence of Cr ions were characterized by X-ray photoelectron spectroscopy. Details of the synthesis and physical characterization is published elsewhere [1]. Photo-modulated reflectance (PR) spectroscopy was performed at room temperature utilizing a mechanically chopped 405 nm line of a 15 mW solid-state laser. The applied laser intensity for PR measurements was kept constant at 33 mW/cm2. Details of the PR system is explained elsewhere [6]. Photo-luminescence (PL) spectroscopy was performed at room temperature utilizing 405 nm line of a 30 mW solid-state laser. In order to improve the PL signals by suppressing wave-guiding effect of the glass substrate, PL signal collection was made under total reflection condition monitored by reflectivity from glass in a secondary photo detector. The electronic structures were calculated based on density functional theory (DFT) of siesta code using GGA exchange-correlation functionals [24]. Photo-modulated reflectance (PR) characterization. PR spectra of the samples are shown in Figs. 1. The structures in the high energy regions are related to the host bandgap Eg (VB→CB) transitions. The Eg values and width (Г) od the transitions were retrieved using a third derivative low electric field model [25], which are 2.47 eV and 0.22eV for the present CGS film without Cr addition. The Eg and Г values are 2.87 eV and 0.03 eV for 1% Cr, and 2.87 and 0.09 eV for 4% Cr-added samples, respectively. The high width values Г indicate the presence of compostional and spatial inhomogeniety in the thin films. On the other hand, Cr addition extend the bandgaps of the host material from 2.47 eV to 2.87 eV. The long tails below the bandgaps are commonly observed in materials when compsitional inhomogeneity is promiment. Inside the host bandgap, as shown in Fig. 1(a), there appears two addtional transitons E D1 and ED2 involving defect bands of CGS native defects. With Cr addtion, transiton strength of both of the defect bands in Fig. 1(b) are much suppressed. This leads to an overall improvement of the PR background in the bandgap region, and observation of PR transitons EIB below the Eg location in the Cr added thin films in Fig. 1(b). This transiton feature

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(VB→IB) indicates the emergence of an impurity band (IB) inside the gap. The energy position EIB is around 2.25 eV.

R/R ( a.u.)

CuGaS2 Fit

ED1

ED2

Eg 1.2

1.4

1.6 1.8 2.0 2.2 2.4 Photon Energy E ( eV)

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Fig 1. Room temperature PR spectra of CuGaS2 thin films without and with Cr impurities. PR features are assigned to two native defects ED1 and ED2 at low energy region, and an impurity bands EIB and bandgaps Eg at high energy region. Least squares fits are drawn for the bandgaps. Photoluminescence (PL) studies. Fig. 2 shows the PL spectra for CGS thin films with different level of Cr dopants. The sharp line at about 1.53 eV is grating-scattered light of the diode-pumped laser (405 nm or 3.06 eV). Another narrow peak at 1.91 eV also originates from the scattered light. Although in standard case optical filters are set to cancel scattered light out, such a measure was not taken in the present experiments in order to allow PL detection from hosts’ high bandgaps. At low energy region, the 1.53 eV line overlapped with a native defect peak, assigned ED1 in PR, and only faintly observed in the CGS without Cr. In the mid energy region, the broad and strong PL peak at the energy around 1.8 eV matches well with the PR assigned peak ED2. This PL signals, in accordance with past reports on MOVPE grown samples [26], can be attributed to a defect band due to low Cu/Ga ratios (<0.84). A similar band is also observed in thin films produced under S-poor conditions, and annealing under S-overpressure has been shown effective to remove the defects [27]. In the present spectra, the ED2 locations are nearly constant with minor red-shifts by around 20 meV in the Cr added samples. The PL intensities of the defect bands are observed reduced with increasing Cr in consistent with a similar trend in PR transition strengths of the defects, and can be attributed to a partial passivation of the native defects due to Cr addition. At the high energy region in Fig. 3, weak PL signals can be observed at around 2.33 eV for the CGS thin film without Cr, and nearly matches with PR assigned Eg peak although around 100 meV away at 2.43 eV. This slight difference can be ascribed to the presence of long low-energy tails observed in PR. Past report show that PL signals often are generated from tail states where strong photo-carrier trapping and re-trapping occur, and give rise to S-shape behaviour in temperature-dependent PL peak traces [28]. An improvement in material homogeneity can reduce this gap. The Cr-added samples did not produce Eg related PL at photon energy up to 2.6 eV beyond which the direct beam of excitation laser affects PL background significantly, and perhaps buries the Eg signals of Cr added samples underneath. The inset of Fig. 2 shows the enlargement of the PL magnitude at the high energy region in which response from the IB band expected. Weak peaks can be observed for the Cr added samples nearly at the host Eg location. Since PR analysis also suggests about the presence of the EIB nearby, it is difficult to differentiate the assignment of the peaks. MMSE Journal. Open Access www.mmse.xyz

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ED2

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Fig.2. Room-temperature PL spectra for the thin films with different Cr contents. PL peaks are assigned to transitions two native defects ED1 and ED2 at low energy region, and bandgaps Eg at high energy regions. The inset 2 shows the enlargement of the PL magnitude between 2.2 – 2.6 eV in which response from the IB band expected. Band structure analysis. In order to analyse the electronic structure, band structures were calculated by first principles theoretical calculations based on density functional theory (DFT). The 2×2×1 super-cell considered in the present work is a 64-atom system consisting four units of conventional 16-atom chalcopyrite tetragonal cells stacked along the x- and y-axes. The corresponding symmetry of the super-cell is the space group 81: P4̅ . In the supercell, one Ga atom was replaced with the Cr atom accounting to the impurity concentration is about 1.56% in total, and 6.25% in Ga sites (or, x = 0.0625). This value is comparable to that used in the present experiments. Calculations have been performed with the SIESTA code [24], an ab initio periodic density-functional method, self-consistent in the local density approximation. Norm-conserving, nonlocal pseudopotentials and linear combination of atomic orbitals have been used. The exchange-correlation effects of the valence electrons were described through the generalized gradient approximation (GGA), within the Perdew-Burke-Ernzerhof (PBE) functional. The Monkhorst-Pack scheme was set 6×6×6 for the pure case, and 3×3×3 for the doping cases for Brillouin zone sampling. In order to get accurate results, we optimized atomic coordinates, which were obtained by minimizing the total energy and atomic forces. The relaxation run was considered converged when the force on the atom was less than 0.04 eV/Å. Before relaxation, experimental values of CGS lattice constants were set, a=5.3512 Å and c/2a0.98 [29]. Then we calculated the electronic structures for each optimized model. Fig. 3 show the band structures along the high symmetrical directions of the Brillouin zone for the CGS and Cr doped crystals. As observed, the band structure of Cr-doped CGS is nearly same to the non-doped one, except that the band-gap is widened and an intermediate band appears in the bandgap. More importantly, the Fermi level exists inside the intermediate band. This suggests that the IB band is partially filled, which is a key requirement in order to realize an operational IBSC via TSPA process. The lowest band gap between the VB and CB is located at Г point, and it’s a direct bandgap with a value of 0.64 eV for the non-doped and 0.88 for the Cr-doped crystals. Although experimental values of our CGS is around 2.4 eV [1], such an underestimation of the calculated bandgaps is an inherent feature of the DFT method.

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Fig 3. The bulk electronic band structure for CuGaS2 (left) and CuGaCrS2 (right) in the DZ-GGA calculations after dynamical relaxation. Spin orientation was set random. The Fermi level of the compound has been set at the energy zero. The diagram is displayed in the main directions of the corresponding first Brillouin zone. Density of states analysis (DOS). The IB band was confirmed by analysing the DOS of the Cr doped CGS. Spin resolved total density of states (DOS) over all atomic orbitals are shown in Fig. 4. The Fermi level has been set at the energy zero. The partially filled IB mainly contains up-spin states while the down spin states maintains the conventional two-band character. These situations fulfil a key requirement in order to realize efficient two-step photon absorption (TSPA) process. There is another spin-band around 0.40 eV below the conduction band (CB). The PR retrieved EIB location is of similar order deeper from the CB, and can be ascribed to the spin-band in Fig. 4. However, further verification is needed to confirm the origin. Because a wide separation of the IB band can limit the thermal excitation of IB electrons and can promote photo-excitation via TSPA, this upper IB band can be made optically active for TSPA if suitable filling of the band can be designed.

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Fig 4. Spin resolved total density of states (DOS) over all atomic orbitals in CuGaS2 with Cr doping. The Fermi level has been set at the energy zero. Summary. The key finding of the present study is the observation of sub-band gap optical response for Cr doped CGS thin films, and its assignment to an intermediate band by means of theoretical band structure evolution. Acknowledgement. This work is supported by New Energy and Industrial Technology Development Organization (NEDO), and Ministry of Economy, Trade and Industry (METI), Japan. Parts of this work was performed under the JSPS fellowship for research program in Japan, and supported by Hirose International Scholarship Foundation, Japan. References [1] S. Kalainathan, N. Ahsan, T. Hoshii, and Y. Okada, "Tailoring of Intermediate Band in CuGaS2 Thin film via Chromium doping by facile chemical Spray Pyrolysis technique," Materials Science in Semiconductor Processing, vol. submitted. [2] Y. Okada, N. J. Ekins-Daukes, T. Kita, R. Tamaki, M. Yoshida, A. Pusch, et al., "Intermediate band solar cells: Recent progress and future directions," Applied Physics Reviews, vol. 2, p. 021302, 2015. [3] A. Luque and A. Martí, "Increasing the Efficiency of Ideal Solar Cells by Photon Induced Transitions at Intermediate Levels," Phys. Rev. Lett., vol. 78, pp. 5014-5017, 1997. [4] A. Martı´, E. Antolı´n, C. R. Stanley, C. D. Farmer, N. Lo´pez, P. Dı´az, et al., "Production of Photocurrent due to Intermediate-to-Conduction-Band Transitions: A Demonstration of a Key Operating Principle of the Intermediate-Band Solar Cell," Phys. Rev. Lett., vol. 97, p. 247701, 2006. [5] N. Ahsan, N. Miyashita, M. M. Islam, K. M. Yu, W. Walukiewicz, and Y. Okada, "Two-photon excitation in an intermediate band solar cell structure," Appl. Phys. Lett., vol. 100, p. 172111, 2012. [6] N. Ahsan, N. Miyashita, M. M. Islam, K. M. Yu, W. Walukiewicz, and Y. Okada, "Effect of Sb on GaNAs Intermediate Band Solar Cells," IEEE J. Photovolt., vol. 3, pp. 730-736, 2013. [7] Y. Okada, T. Morioka, K. Yoshida, R. Oshima, Y. Shoji, T. Inoue, et al., "Increase in photocurrent by optical transitions via intermediate quantum states in direct-doped InAs/GaNAs straincompensated quantum dot solar cell," Journal of Applied Physics, vol. 109, p. 024301, 2011. MMSE Journal. Open Access www.mmse.xyz

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[8] T. Tanaka, K. M. Yu, A. Levander, O. Dubon, L. Reichertz, N. Lopez, et al., "Demonstration of ZnTe1-xOx Intermediate Band Solar Cell," Jpn. J. Appl. Phys., vol. 50, p. 082304, 2011. [9] T. Tanaka, M. Miyabara, Y. Nagao, K. Saito, Q. Guo, M. Nishio, et al., "Photogenerated Current By Two-Step Photon Excitation in ZnTeO Intermediate Band Solar Cells with n-ZnO Window Layer," IEEE J. Photovolt., vol. 4, p. 196, 2014. [10] N. Lo´pez, L. A. Reichertz, K. M. Yu, K. Campman, and W. Walukiewicz, "Engineering the Electronic Band Structure for Multiband Solar Cells," Phys. Rev. Lett., vol. 106, p. 028701, 2011. [11] R. Oshima, A. Takata, and Y. Okada, "Strain-compensated InAs/GaNAs quantum dots for use in high-efficiency solar cells," Appl. Phys. Lett., vol. 93, p. 083111, 2008. [12] J. Wu, D. Shao, Z. Li, M. O. Manasreh, V. P. Kunets, Z. M. Wang, et al., "Intermediate-band material based on GaAs quantum rings for solar cells," Appl. Phys. Lett., vol. 95, p. 071908, 2009. [13] W. Walukiewicz, W. Shan, K. M. Yu, J. W. A. III, E. E. Haller, I. Miotkowski, et al., "Interaction of Localized Electronic States with the Conduction Band: Band Anticrossing in II-VI Semiconductor Ternaries," Phys. Rev. Lett., vol. 85, p. 1552, 2000. [14] J. Wu, W. Walukiewicz, K. M. Yu, J. W. Ager, E. E. Haller, I. Miotkowski, et al., "Origin of the large band-gap bowing in highly mismatched semiconductor alloys," Phys. Rev. B, vol. 67, p. 035207, 2003. [15] W. Shan, K. M. Yu, W. Walukiewicz, J. Wu, J. W. A. III, and E. E. Haller, "Band anticrossing in dilute nitrides," J. Phys.: Cond. Mat., vol. 16, p. S3355, 2004. [16] Y. Dai, M. A. Slocum, Z. Bittner, S. Hellstroem, D. V. Forbes, and S. M. Hubbard, "Optimization in wide-band-gap quantum dot solar cells," 43rd IEEE Photovoltaic Specialists Conference (PVSC), pp. 0151 - 0154, 2016. [17] W.-J. Jeong and G.-C. Park, "Structural and electrical properties of CuGaS2 thin films by electron beam evaporation," Solar Energy Materials & Solar Cells, vol. 75, pp. 93 –100, 2003. [18] A. Martí, D. F. Marrón, and A. Luque, "Evaluation of the efficiency potential of intermediate band solar cells based on thin-film chalcopyrite materials," J. Appl. Phys., vol. 103, p. 073706, 2008. [19] K. Sato and T. Teranishi, "Effect of Delocalization of d-Electrons on the Optical Reflectivity Spectra of CuGa1-xFexS2 and CuAl1-xFexS2 Systems," Jpn. J. Appl. Phys., vol. 19, pp. 101 - 105, 1980. [20] P. Palacios, K. Sánchez, J. C. Conesa, J. J. Fernández, and P. Wahnón, "Theoretical modelling of intermediate band solar cell materials based on metal-doped chalcopyrite compounds," Thin Solid Films, vol. 515, pp. 6280 –6284, 2007. [21] Y.-J. Zhao and A. Zunger, "Electronic structure and ferromagnetism of Mn-substituted CuAlS2, CuGaS2, CuInS2, CuGaSe2, and CuGaTe2," Phys. Rev. B, vol. 69, p. 104422, 2004. [22] P. Palacios, I. Aguilera, P. Wahnón, and J. C. Conesa, "Thermodynamics of the Formation of Tiand Cr-doped CuGaS2 Intermediate-band Photovoltaic Materials," J. Phys. Chem. C, vol. 112, pp. 9525 - 9529, 2008. [23] Y. Seminóvski, P. Palacios, and P. Wahnón, "Intermediate band position modulated by Zn addition in Ti doped CuGaS2," Thin Solid Films, vol. 519, pp. 7517 - 7521, 2011. [24] J. M. Soler, E. Artacho, J. D. Gale, A. García, J. Junquera, P. Ordejón, et al., "The SIESTA method for ab initio order-N materials simulation," Journal of Physics: Condensed Matter, vol. 14, p. 2745, 2002. [25] D. E. Aspnes, "Third-derivative modulation spectroscopy with low-field electroreflectance," Surf. Sci., vol. 37, pp. 418–442, 1973.

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[26] J. R. Botha, M. S. Branch, P. R. Berndt, A. W. R. Leitch, and J. Weber, "Defect chemistry in CuGaS2 thin films: A photoluminescence study," Thin Solid Films, vol. 515, pp. 6246-6251, 2007. [27] G. MassĂŠ, "Luminescence of CuGaS2," J. Appl. Phys., vol. 58, pp. 930 - 935, 1985. [28] N. Ahsan, N. Miyashita, K. M. Yu, W. Walukiewicz, and Y. Okada, "Improving multiband character of GaNAs," Submitted. [29] A. H. Romero, M. Cardona, R. K. Kremer, R. Lauck, G. Siegle, C. Hoch, et al., "Electronic and phononic properties of the chalcopyrite CuGaS2," Phys. Rev. B, vol. 83, p. 195208, 2011. Cite the paper N. Ahsan, S. Kalainathan, N. Miyashita, T. Hoshii, Y. Okada (2017). Characterization of Cr Doped CuGaS2 Thin Films Synthesized By Chemical Spray Pyrolysis. Mechanics, Materials Science & Engineering, Vol 9. doi:10.2412/mmse.53.55.304

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Deposition and Characterisation of Zinc Telluride as a Back Surface Field Layer in Photovoltaic Applications Srimathy N.1, A. Ruban Kumar1,a 1 – School of Advanced Sciences, VIT University, Vellore. 632014, India a – arubankumar@vit.ac.in DOI 10.2412/mmse.32.15.18 provided by Seo4U.link

Keywords: thermal evaporation, XRD, AFM, Raman spectroscopy, cubic structure.

ABSTRACT. Zinc Telluride films developed by Thermal evaporation technique has wide application in photovoltaic and optoelectronic applications. ZnTe films at 423K and 473K were deposited onto glass substrates and annealed at 573K. Structural studies were carried out by XRD technique and Morphological study was done by AFM which in turn shows the high intensity peak at annealed condition. Optical properties was studied by UV-VIS spectrometer to find the energy distribution and thereby, bandgap is calculated, which ranges from 1.89eV to 2.42eV. Raman analysis was done to find the phonon distribution and molecular longitudinal modes.

Introduction. Zinc Telluride is an interesting II–VI p-type semiconductor material for its application for photovoltaic and optoelectronic applications. It is highly transparent towards visible region with a band gap ranging from 2.4 to 2.6 eV. Because of these high stability propertiesThe inability of the other types of solar cells can be defined due to other losses in efficiency say, surface recombination, disqualified solar spectrum and other factors. These factors can be overcome by using efficient direct band gap semiconductors with optimized bandgap [2]. Commercially, it is proven that Thermal evaporation is the user-friendly and easy handling technology for Zinc Telluride deposition for various reasons. Since the distance between the substrate and the source can be adjustable, the thickness can be monitored and stabilized for various applications. Experimental Description. Zinc Telluride is red- brownish polycrystalline powder with the purity of 99.999%, loaded with the tungsten boat for evaporation. The chamber is maintained with the base pressure of approx. 10-5 torr. Once the source attains the melting temperature of the Zinc Telluride, Evaporation starts and the film get deposited into the glass substrate. Here the substrate temperature is maintained at 423K. The evaporation was done for 15 min, and the thickness of the film was measured using the quartz crystal monitor attached to the thermal evaporation chamber. Unique thickness can be maintained by fixed deposition charge and time. The deposition process depends on the various factors such as the substrate temperature, nature of the source material, melting point of the source material and the base vacuum pressure. The thickness was maintained at 300 nm for both the temperatures. Now the samples were annealed at 573K in an inert atmosphere , here, Argon atmosphere for 5hr under vacuum. The entire procedure is repeated, only changing the substrate temperature to 473K. The deposition procedure and the thickness is maintained the same with the only difference of the substrate temperature, followed by same annealing procedure. The samples are then investigated with various characterization techniques before and after annealing for comparison. XRD (X-Ray Diffraction) technique (XRD, Brucker D8 Advance, Cu Kα radiation, λ= 1.5406 Å), was used to analyse the structural properties of ZnTe. The surface properties was studied by Atomic force microscopy (AFM). Optical properties like Transmission and Reflection was measured using UV-VIS spectrometer which in turn, the absorption coefficient, α, can be calculated [4]. MMSE Journal. Open Access www.mmse.xyz

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where d is the thickness of the film, R and T represent the reflection and transmission coefficients from the reflection and transmission spectrum respectively. Results and discussion Structural Properties. XRD is an important analytical tool to find the structural properties of any material. Bruker X-ray diffractometer is used for this study, which is operated with 40kV and 10 mA, with the azimuthal distribution of copper with a wavelength of λ = 1.540 Å .The sample holder was rotated inside with a speed of 1 deg/min placed vertically. A graph was plotted with the intensities versus azimuthal angle. Typical XRD patterns obtained shows that the ZnTe films show the (Cubic) Zinc Blende structure which is an essential characteristic for the back surface layer to find its application in Photovoltaic. The interplanar spacing with corresponding diffraction intensities were calculated by Bragg’s Equation [5]

where dhkl represents the interplanar spacing, hkl, the corresponding miller indices. The results obtained are compared with the standard, JCPDS 04-0850 file data.The orientation of the XRD peaks are found to be in (111) planes, with the additional peaks in (222) and (220) planes. After Annealing, the peaks were found to be more prominent compared to the initial peaks. It is clearly seen from the Figure 1.

Fig. 1. XRD patterns for ZnTe at 423K and 473K, before and after annealing. MMSE Journal. Open Access www.mmse.xyz

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The patterns clearly show that the intensity of peaks increases after annealing. This shows that the temperature annealing cleanses the surface contamination and hence providing a promising BSF layer [6]. Thus, a peak at 2Î¸ at 450, was observed to show that the Cubic Telluride crystals with Zinc Blende structure. This peak shows that the telluride crystals are found huge in the film which is due to the annealing treatment. Because of the diffusing character of Telluride crystals, the Zinc acts as a host to accept the crystals to form a uniform thin film layer. Usually Zinc Telluride films at low temperatures have high dislocation density and formation of strain in films, which is not observed in Films deposited at higher temperatures. The annealing at 573K, has capability of decreasing the trend of strain and thus increases the crystallites formation. Also, the size of the crystallites varies as the temperature increases. ZnTe films have the capability of aligning themselves to the nature of heat treatment and processing. Physical Properties.The surface morphology of the ZnTe films was determined by Atomic Force Microscopy (AFM). The method used to analyse the surface properties of ZnTe was by Non-contact method, wherein the points of contact of probe will not contact the surface of the film. Here, ZnTe films developed at 423K and 473K with their corresponding annealed films were investigated. Usually, ZnTe films at 300 to 400 nm thickness, are highly minced, with pointed grain size. The effects of temperature dependence of the films were evaluated with their annealing behavior[7]. Film deposited at 423K exhibits an average roughness of about 4.23nm, and at 473K, it is 5.76nm. After annealing, it is observed that the large grains of the film protrude due to the temperature absorption. Hence, this shows the high intense peaks of the film at higher temperatures. The average roughness was found to be 4.01nm at 423K and 4.98nm at 473K respectively. Figure.2, 3, 4 & 5 shows the AFM images of ZnTe films deposited at 423K and 473K before and after annealing respectively. It is clearly shown that there were large crystallites of the film in annealed films after heat treatment in Argon atmosphere [8]. This is due to the fact the process of reduction occurs in the films when annealed at 573K. It is clear from the earlier publications that the film has the capability absorbing higher temperatures which in turn does not affect the actual properties of the film. Hence such prominent behavior of ZnTe films have wide application towards the Photovoltaic properties. It is also clear from the AFM images that as the substrate temperature increases the density of the film increases and the intensity of the peaks become highly fixed to exhibit their structural behavior suitable for the solar applications.

Fig. 2. AFM image of ZnTe deposited at 423K before annealing.

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Fig. 3. AFM image of ZnTe deposited at 423K after annealing.

Fig .4. AFM image of ZnTe deposited at 473K before annealing.

Fig. 5. AFM image of ZnTe deposited at 473K after annealing.

Optical Properties. Semiconductor with the 1.85eV to 2.5eV can be used in photovoltaic application, which is an essential property for the film, as BSF layer. Transmission and absorption spectra was obtained from the Shimadzu, UV-VIS spectrometer. It is clear that the films before annealing treatment exhibits were highly transparent compared to the films after annealing [9]. It is clear from the Figure.6 and Figure.7 that the transmission spectra of the film deposited at 423K and 473K, before and after annealing, which is highly discrete with sequential format.

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Fig. 6. Transmission Spectra of ZnTe film deposited at 423K, and 473K before annealing.

Fig. 7. Transmission Spectra of ZnTe film deposited at 423K, and 473K after annealing.

The decrease in transmission spectra of films after annealing was due to the fact that there was a change in stoichiometry and structural improvement in the films due to the high absorption of temperature. It is clearly shown from the results of transmission spectra of the film. The swanpoel method [10] was used to calculate the absortion coefficients of the film from the reflection measured [11]. Also, the Bandgap is also measured from the following formula: α⋅ hυ = Aa (hυ− Eg )1/ 2 where hυ represents the energy of the incident photon, Eg represents the energy band gap. It is found to be in the range of 1.89eV to 2.42eV. It is an important property for a film to exhibit its performance, as a BSF layer [12]. Raman spectroscopy. Raman is proved to be one of the useful tool for the spectroscopic analysis of the thin films. As ZnTe films are one of the promising films for the photovoltaic applications, it is essential for the film to exhibit Raman properties [13]. Due to various factors such as molecular vibration, material stress and its structural disorder, there can be variation of Raman spectra of the film deposited at different temperatures [14]. It is clear from the images that the annealing affect of the films exhibit good Raman scattering at both elastic and inelastic modes of spectra. Any mismatch in the lattice structures as well as molecular distribution can be overcome by annealing at higher temperatures. There is also a possibility of heating effect of high power laser density which in turn can damage the film under investigation [15]. MMSE Journal. Open Access www.mmse.xyz

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Fig. 8. Raman Spectra of ZnTe at 423K and 473K before and after annealing respectively. It is clear from the images that the ZnTe films exhibit the Raman Spectra at 205cm-1, 410cm-1 and 620cm-1 respectively. These longitudinal mode of phonon is identical for the photovoltaic application for its application as a BSF field. The Raman spectra obtained from both the films are due to the Telluride bands that exists in the ZnTe films which is due to the 205cm-1 longitudinal phonon mode [16]. Thus the results of Raman spectroscopy helps in better understanding of the phonon level distribution of molecules in the film. It is clearly depicted that the Films annealed at higher temperatures have good quality of performance as a BSF layer inside the photovoltaic thin films [17]. Still, this Raman spectra does not profile the complete analysis of films, further study at different intensities of study is required to map the behavior of such thin films. Summary. The study shows that the annealed films at higher temperatures exhibit a good BSF layer, compared to the film properties before annealing. XRD studies clearly shows that Cubic Zinc Blende structure and which is an essential structure for a molecule as a BSF layer. AFM results also depicted a prominent high intensity peaks of annealed film than a non- annealed film [18]. Absorption spectra and the bandgap thus calculated ranges from 1.89eV to 2.42eV, which is the most optimistic character for a BSF layer in thin film solar cells. Raman spectroscopy yielded very unique information about the phonon properties and the surface molecular composition of the ZnTe before and after annealing. This investigation shows that the annealed ZnTe exhibits better BSF layer properties compared to the non-annealed ZnTe films. Still further characterisation studies can provide better information, which will be investigated further. Acknowledgement. Authors would like to thank Mr. Sanjith for his kind support and Mrs. Sunita for the facilities provided for this study. I like to gratefully acknowledge their presence in this study. References [1] Nazar Abbas Shah, Waqar Mahmood, Thin solid Films, “Physical properties of sublimated zinc telluride thin films for solar cell applications”. DOI: 10.1016/j.tsf.2013.03.088 [2] T. L. Chu, Shirley S. Chu, F. Firszt, and Chuck Herrington, Journal of Applied Physics, “Deposition and properties of zinc telluride and cadmium zinc telluride films”. DOI: http://dx.doi.org/10.1063/1.336514 [3] Michael Neumann-Spallart, Christian Kiinigstein , Thin Solid Films, “Electrodeposition of zinc telluride”. DOI: http://dx.doi.org/10.1016/0040-6090(95)06641-1 [4] M. Rusu, I. Salaoru, M. E. Popa, G. I. Rusu, Intern.J. Mod. Phys. B18, 1287 (2004). DOI:10.1.1.518.6368...

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[5] B. D. Cullity, Elements of X-ray Diffraction, Addison-Wesley, Reading, Massachusetts 356, (1979). [6] H. Venghaus, P.J.Dean, Phy.Rev.B, “Shallow-acceptor, donor, free-exciton, and bound-exciton states in high-purity zinc telluride” DOI: https://doi.org/10.1103/PhysRevB.21.1596 [7] M. R. H. Khan, J. Phys D Appl. Phys. 27, 2190 (1994). DOI: 10.1088/0256-307X/24/10/072 [8] W. I. Tao, M. Jurkovic, I. N. DOI: http://dx.doi.org/10.1063/1.126297

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[11] J. C. Manifacier, J. Gasiot, J. P. Fillard, L. Vicario,Thin Solid Films 41, 127 (1977); 37, 329 (2002) DOI: 10.1.1.518.6368&rep=rep1&type=pdf [12] A. Kaneta, S. Adachi, J. Phys. D: Appl. Phys. 33 (2000) 901. DOI: 10.1143/JJAP.31.3907/meta [13] A. Pistone, A.S. Arico, P.L. Antonucci, D. Silvestro, V. Antonucci, Solar Energy Mater. Solar Cells 53 (1998) 255. DOI: 10.5772/50964 [14] M.A. Bozzini, M.A. Baker, P.L. Cavallotti, E. Cerri, C. Lenardi, Thin Solid Films 361y362 (2000) 388. DOI: http://dx.doi.org/10.1016/S0040-6090(99)00771-3 [15] A.S. Arico, D. Silvestro, P.L. Antonucci, N. Giordano, V. Antonucci, Adv. Perform. Mater. 4 (1997) 115. DOI: 10.4028/www.scientific.net/AMM.535.688 [16] A. Mondal, B.E. McCandless, R.W. Birkmire, Solar Energy Mater. Solar Cells 26 (1992) 181. DOI: http://dx.doi.org/10.1016/0927-0248(92)90059-X [17] B.D. Cullity, Elements of X-ray diffraction, 2nd ed., Addition–Wesley Publishing Inc, 1967, p. 356. [18] U. Pal, S. Saha, A.K. Chaudhuri, V.V. Rao, H.D. Banerjee, J. Phys. D: Appl. Phys. 22 (1989) 965. DOI: 10.1088/0022-3727/22/7/014/meta

Cite the paper Srimathy N., A. Ruban Kumar (2017). Deposition and Characterisation of Zinc Telluride as a Back Surface Field Layer in Photovoltaic Applications. Mechanics, Materials Science & Engineering, Vol 9. doi:10.2412/mmse.32.15.18

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Phtotocatalytic Degradation of Methyelene Blue by Cu Doped TiO2 Thin Films under Visible Light Irradiation Vidhya Rajendran1,a, Gandhimathi Rajendran2, Neyvasagam Karuppathevar 3,b 1 – Department of Physics, V.V.V College for women, Virudhunager-626001, India 2 – Department of Physics, AMET University, Kanathur, Chennai-603112, India 3 – Department of Physics, The Madura College, Madurai-625011, India

a – vidhya3vc@gmail.com b – srineyvas@yahoo.co.in DOI 10.2412/mmse.81.84.608 provided by Seo4U.link

Keywords: Cu-TiO2, thin films, XRD, SEM, UV-Visible, phtotocatalytic activity.

ABSTRACT. Pure TiO2 and Copper doped TiO2 thin films of various concentrations (0.02–0.05 mol %) have been successfully deposited onto glass substrate by sol-gel dip coating technique and annealed at 400ºC for 3 hours. The XRD results showed the presence of anatase phase for all the films and the crystallite size decreases with increasing doping concentrations. The morphological observations and compositional analysis were recorded with SEM and EDX. The UVVisible study showed that the optical band gap energy decreases with increasing Cu content. It was also found that copper doping shifted the absorption edge of TiO2 toward a visible regime depicting the possible modification in the electronic band structure. The photocatalytic activity was evaluated by monitoring the degradation of methyelene blue under visible light illumination. It was found that the percentage of degradation was higher in 0.05mol% Cu-TiO2 when compared with other films. The efficiency of the Cu-TiO2 thin film was preserved even after the extended usage of the films which sustains the reusability nature of Cu-TiO2 films.

Introduction. Titanium dioxide (TiO2) has been extensively studied because of its excellent phtotocatalytic activity, chemical stability, non toxicity, optoelectronic property and low cost. However, the wide band gap and intense electron-hole pair recombination limit its efficiency in photo electro chemical applications. Tailoring the band structure of TiO 2 is an effective method for widening its optical absorption range and improving its visible light phtotocatalytic activity [1, 2]. Catalytic activity of TiO2 is dependent on its phase structure, crystallite size, specific surface area and pore structure. Doping additives were found successful in altering the photo electrochemical properties of TiO2 [3, 4]. In particular, doping metal impurity in TiO2 matrix has been found remarkable as the way it exploits the better photo catalytic activity [5, 6]. Cu is a potential metal dopant for phtotocatalytic mechanism since the visible light absorption of TiO2 can be enhanced by the adding Cu [7]. Here the efforts have been made to prepare Cu doped TiO 2 film because the film shaped photocatalysts are convenient to use and recyclable. There are numerous methods to prepare Cu doped TiO2 thin film but the sol-gel method shows more advantages over other methods [8]. By carrying out this method in solution, we can modify the few desired structural characteristics like compositional homogeneity, grain size, surface morphology and porosity is possible with this technique. Methyelene blue is a harmful material existing in liquid coming from industries. Exposure to methyelene blue causes various health issues such as increased heart beat rate, vomiting, shock, jaundice and tissue necrosis in human being. Cu doped TiO2 thin film can be used to photo degrade the methyelene blue in waste water. In this work, pure TiO2 and Copper doped TiO2 thin films with various Cu concentrations (0.02-0.05 mol %) were prepared by sol-gel technique. The structural and optical properties of the samples were reported. The phtotocatalytic activity of prepared films was evaluated by methyelene blue degradation under visible light irradiation. MMSE Journal. Open Access www.mmse.xyz

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Experimental methods. The pure TiO2 and Cu doped TiO2 thin films were prepared by sol-gel method. Titanium tetra isopropoxide (Merk 95%) precursor was dissolved into ethanol and the mixture was stirred at room temperature for 15 minutes. To this mixture acetic acid was added as a chelating agent and stirred for 15 minutes. Titanium tetra isopropoxide, ethanol and acetic acid were used in the molar ratio of 1.5:10:0.3. In the process of copper doping, copper II nitrate trihydrate was dissolved in ethanol in the respective molar ratio (Cu/TiO2 = 0.02, 0.03, 0.04 and 0.05 mol%) was mixed with TiO2 gel and stirred in a magnetic stirrer for two hour for uniform dispersion. The CuTiO2 sol were deposited on glass substrates by dip coating process at room temperature with the drawing speed of about 1.5 mm/s. The coated samples were dried at 100ºC for 10 minutes and the process was repeated to obtain the desired thickness. The pure TiO 2 was also synthesized using the same procedure without the addition of copper precursor and all are annealed at 400ºC for 3 hour. Results and discussions. Structural analysis.

Fig. 1. XRD pattern of Cu-TiO2 films with various Cu doping concentrations. The XRD pattern of pure and Cu doped TiO2 thin films with different concentrations are shown in Fig.1. Both undoped and Cu-doped TiO2 films show pure anatase phase with strong peak (1 0 1) at 2θ=25.5º which is in agreement with JCPDS card no 89-4203 [9]. However, no peaks related to Cu impurities are found due to the low doping concentrations of Cu or the Cu metal ions have been well dispersed into the TiO2 matrix in the form of small cluster [10]. The crystallite size of as-synthesized samples were estimated from Scherrer’s equation using the full width at half maximum of the (1 0 1) peak of anatase TiO2. It was perceived that the crystallite size decreases with the increased Cu proportions [11] as the stress created by the difference in ionic radii of Ti4+ (0.75Å) and Cu2+ (0.87Å). Furthermore a large number of dislocations were initiated when Cu ions occupying interstitial sites within Ti lattice which led to decrease in crystallize size [12]. Surface morphological analysis. The microstructure and chemical composition of Cu-TiO2 thin films were characterized using SEM and EDX. Fig.2 shows the SEM and EDX images of 0.04mol% Cu-TiO2 thin films. The SEM image illustrates a few localized agglomerations with cracked patterns [13]. The crack formation was possibly by the repeated process done to make thicker coatings of films

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(7-layered) [14]. The energy dispersive spectrum (EDX) exposes the presence of titanium, copper and oxygen in appropriate proportions.

Fig. 2. SEM and EDX spectrum of Cu-TiO2 (0.04mol %) thin film. Optical Analysis

Fig. 3. Absorption spectra of Cu-TiO2 films with various Cu doping concentrations. The UV-visible absorption spectra of pure TiO2 and Cu-TiO2 films are shown in Fig.3. It was viewed that the pure TiO2 shows UV light absorption as it requires maximum energy for the transition of electrons from the top of the valence band to the bottom of the conduction band (wide band gap). Conversely Cu-TiO2 demonstrates enhancement in visible light absorption as Cu doping creates new electronic levels and reduces the band gap energy requirement. Accordingly the absorption edge of MMSE Journal. Open Access www.mmse.xyz

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TiO2 was shifted towards visible light region [15]. Widening the absorption edge to the visible region can upraise the phtotocatalytic activity reasonably [16]. Phtotocatalytic activity. Phtotocatalytic activity of TiO2 and Cu doped TiO2 thin films was analyzed by examining the degradation of aqueous solution of methyelene blue (MB) under visible light irradiation using 500-W halogen lamp. In order to carry out the process, 3Âľml of the methyelene blue was mixed with 30ml water in a 50-ml beaker. The thin films were soaked into this and kept under visible light irradiation for 0,1,2,3 and 4 hour. After that the 5ml of the degradation solution was taken to measure the absorbance using Schimadzu-1800 UV-Vis spectrometer.

Fig. 4. Optical absorption spectra of degradation of MB dye for Cu-TiO2 thin films. Fig. 4 show the absorbance spectra of degraded MB with different time periods (3 hr and 4hr) of pure TiO2 and Cu-TiO2 thin films. It was observed that the doped TiO2 films depict enhanced catalytic activity than undoped film. The interpretation is that due to illumination, the generated electron-hole pair is transferred to the surface of photo catalyst which excites electrons of the pollutant to the conduction band of TiO2 [17, 18]. Here Cu doping delays electron-hole recombination and thus by promotes the photo induced interfacial charge-transfer between Cu ion and TiO2 energy levels. This leads to the production of more reactive species.

Fig. 5. (a) Percentage of degradation of MB (b) Reusability of the film. MMSE Journal. Open Access www.mmse.xyz

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The produced OH and O2- radicals oxidize and decompose the molecules of MB photo reactor. As a result, the characteristic color of MB dye was degraded with time. The photo catalytic mechanism is influenced by the degradation time too. Hence the absorption peaks corresponding to the MB decreases further to a minimum value with increase in time. The percentage of degradation of MB is shown in Fig. 5a. The 0.05 mol% Cu doped TiO2 thin films show the highest percentage of degradation (92%) than that of pure TiO2 (68%). This is attributed to that the smaller particle size of 0.05 mol% Cu-TiO2 compared to that of pure TiO2 as the photo bleaching process rely upon particle size, crystallinity and surface area. Also, the larger surface area facilitates the films to have more adsorption site and enhances the surface contact between photo reactor MB and Cu-TiO2 catalyst. Consequently fast degradation process has taken place under visible light irradiation. Thus with 0.02 to 0.05 mol% stochiometric range, Cu dopant promotes the reaction rate and increases decolorisation efficiency appreciably. One of the important features of thin film catalyst is its reusability. This catalyst could be easily recovered by cleaning with water and reused without loss of its catalytic activity [19]. Hence to calculate Cu-TiO2 catalyst stability, the film was undergone with 6 cycles of photo degradation in MB dye under visible light irradiation. Here, we report the reusability of 0.05 mol% of Cu-TiO2 thin film. After each cycle, the film was washed with distilled water, dried in air and reused in same conditions. The catalytic efficiency was evaluated in each cycle. It was noticed that it maintains its excellent catalytic efficiency even after 6 cycles with a small loss which is shown in Fig. 5b.The CuTiO2 thin film (0.05mol %) was preferred for testing the reusability since it showed the improved catalytic performance than all other prepared films in degradation of dyes. Summary. Pure TiO2 and Cu doped TiO2 with different concentrations were deposited on glass substrates by sol-gel dip coating technique. The presence of anatase phase and decreasing crystallite size with the increasing Cu ratio were spotted from the recorded XRD pattern. The morphology study reveals that the surface of the film was comprised with agglomerated flakes like structure and the existence of Cu, Ti and O elements are confirmed from EDX measurements. Copper doping shifted the absorption edge of TiO2 towards the visible light region. The TiO2 thin film doped with 0.05 mol % Cu exhibits strong photo catalytic activity thus by drawing higher percentage of methyelene blue degradation. The aptness of the Cu-TiO2 thin film as a photo catalyst with the repeated usages was found to be excellent. References [1] H. Pan,Y.W. Zhang,V.B. Shenoy and H. Gao, Effects of H-, N-, and (H, N)-Doping on the PhotocatalyticActivity of TiO2, J. Phys. Chem. C, 2011, 115(24), 12224-12231. DOI: 10.1021/jp202385q. [2] M. Khan,W. Cao and M. Ullah, Ab initio calculations for theelectronic and optical properties of Y-doped anatase TiO2, Phys. Status Solidi B, 2013,250(2), 364-369. DOI: 10.1002/pssb.201248174. [3] X.Cheng,X.YuandZ.Xing,Characterization and mechanism analysis of Moâ&#x20AC;&#x201C;N-co-doped TiO2 nano-photocatalyst and its enhanced visible activity J.ColloidInterf.Sci.,2012,372(1), 1-5. DOI: 10.1016/j.jcis.2011.11.071. [4] Y.Ma,M.Xing,J.Zhang,B.TianandF.Chen,Synthesis of well ordered mesoporous Yb, N co-doped TiO2 with superiorvisible photocatalytic activity, Micropor.Mesopor.Mater.,2012, 156, 142-152. DOI:10.1016/j.micromeso.2012.02.010. [5] C. Su, L. Liu, M. Zhang, Y. Zhang and C. Shao, Fabrication of Ag/TiO2 nanoheterostructures with visible light photocatalyticfunction via a solvothermal approach, Cryst.Eng.Comm., 2012,14, 3989-3999. DOI: 10.1039/C2CE25161B. [6] I.E.Saliby,L.Erdei,H.K.ShonandJH.Kim,Development of visible light sensitive titania photocatalysts by combinednitrogen and silver dopingJ.Eng.Chem.,2011,17(2),358363.DOI:10.1016/j.jiec.2011.02.039 MMSE Journal. Open Access www.mmse.xyz

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[7] F. Bensouici , M. Bououdina , A. A. Dakhel , R.Tala-Ighil , M.Tounane , A.Iratni , T. Souier , S. Liu , W. Cai,Optical, Structural and Photocatalysis Properties ofCu-Doped TiO2 Thin Films, Appl. Surf.Sci., 2016. DOI:10.1016/j.apsusc.2016.07.034. [8] C. He, Y. Yu, X. Hu and A. Larbot, Influence of silver coating on the photocatalytic activity of titania film, Appl. Surf.Sci., 2002, 200, 239-247. DOI:10.1016/S0169-4332(02)00927-3. [9] H.E. Swanson, E. Talge, Standard X-ray diffraction patterns, J. Res. Nat. Bur.Stand 1951. [10] Z. Oman and B. Harry,Synthesis of Nanostructured Copper-doped Titaniaand Its Properties, Nano-Micro Lett., 2013,5(1), 26-33. DOI:10.3786/nml.v5i1.p26-33. [11] P. Dharmarajan, A. Sabastiyan, M. Yosuvasuvaikin, S. Titus and C. Muthukumar, Photocatalytic Degradation of Reactive Dyes in Effluents Employing Copper Doped Titanium Dioxide Nanocrystals and Direct Sunlight, Chem Sci. Trans, 2013, 2(4), 1450-1458. DOI:10.7598/cst2013.575. [12] Biswajitchoudhury,Munmun Deyand Amarjyotichoudhury, Defect generation, d-d transition, and band gapreduction in Cu-doped TiO2 nanoparticles, International Nano Letters, 2013, 3:25. DOI: 10.1186/2228-5326-3-25. [13] P. Malliga, J. Pandiarajan, N. Prithivikumaran, K. Neyvasagam, Influence of Film Thickness on Structural and Optical Properties of Sol â&#x20AC;&#x201C; Gel Spin Coated TiO2 Thin Film, IOSR Journal of Applied physics, 2014, 6, 22-28. e-ISSN: 2278-4861. [14] Mustafa Erol, OrkutSacakoglu, Omer mermer, Erdalcelik, Degradation of Contaminated Industrial Waste Water using Sol-Gel Derived Ru-doped TiO2 Photocatalytic Films, Ekoloji 2013, 22, 13-22. DOI: 10.5053/ekoloji.2013.882 [15] J. Zhu, Y. Zhang, X.S.Zhao and A.K. Ray, Photodegradation of Benzoic Acid over Metal-Doped TiO2, Ind. Eng. Chem. Res., 2006, 45, 3503-3511.DOI: 10.1021/ie051098z. [16] Matillah khan, Sahar Ramingl, Jing L and Wenbncao, Photocatalytic Degradation of Methylene Blue byHydrothermally Prepared Ag-Doped TiO2Under Visible Light Irradiations, The minerals, metals & materials Society, 2015, 67(9), 2104-2107. DOI: 10.1007/s11837-015-1486-5. [17] X. Yiming and C.H. Langford,UV- or Visible-Light-Induced Degradation of X3B on TiO2 Nanoparticles:The Influence of Adsorption, Langmuir, 2001, 17, 897-902. DOI: 10.1021/la001110m. [18] A.B. Prevot, C. Baiocchi, M.C. Brussino, E. Pramauro, P. Savarini, V. Augugliaro, G. Marci, L. Palmisano, PhotocatalyticDegradation of AcidBlue 80 in Aqueous SolutionsContaining TiO2 SuspensionsEnvironmental Science & Technology, 2001, 35, 971-976. DOI: 10.1021/es000162v. [19] MahtabPirouzmand, Adel MahmoudiGharehbaba, ZarrinGhasemi and SajjadAziziKhaaje, [CTA]Fe/MCM-41: An efficient and reusablecatalyst for green synthesis of xanthene derivativesArbian journal of chemistry 2016, DOI:10.1016/j.arabjc.2016.06.017.

Cite the paper Vidhya Rajendran, Gandhimathi Rajendran, Neyvasagam Karuppathevar (2017). Phtotocatalytic Degradation of Methyelene Blue by Cu Doped TiO2 Thin Films under Visible Light Irradiation. Mechanics, Materials Science & Engineering, Vol 9. doi:10.2412/mmse.81.84.608

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Highly Porous and Novel 1D-TiO2 Nanoarchitecture with Light Harvesting Morphology for Photovoltaic Applications K. Pugazhendhi1, W. Jothi Jeyarani1, Tenzin Tenkyong1, P. Naveen Kumar1, B. Praveen1, J. Merline Shyla1 1 – Department of Physics, Energy NanoTechnology Centre (ENTeC), Loyola Institute of Frontier Energy (LIFE), Loyola College, Chennai, India DOI 10.2412/mmse.3.32.722 provided by Seo4U.link

Keywords: photoanode, dandelion-like TiO2 structures, nanowire, solvothermal, light harvesting.

ABSTRACT. A novel photoanode architecture revamped by dandelion-like TiO2 (DS) structures as light harvesting ingredients over the vertically oriented TiO2 nanowire (NW) bunches has been prepared on FTO glass without any seed layer through a single-step solvothermal process. High Resolution SEM observations showed that the synthesized photoanode consists of dandelion-like structures over vertically oriented nanowires with high surface porosity. Both the nanowire and dandelion structures possess rutile TiO2 crystal phase as confirmed with XRD analysis which also revealed that the nanoarchitecture is single crystalline, an essential condition for faster electron transport at the interfaces. The enhanced light harvesting capabilities and bandgap were examined using UV-DRS. Field dependent dark and photo conductivity measurements were performed to observe the response of the material to the visible spectrum. The proposed photoanode incorporating 1D-TiO2 electron transporters provides a novel configuration for improved light harvesting application.

Introduction. Demand for energy finds first place in the list of humanity’s top ten problems to be faced in the next 50 years [1]. The biggest challenge of our modern society is to find and replace the gradually vanishing conventional energy resources by renewable energy resources and at the same time ensuring safety, cleanliness and eco-friendly approach. Among the various sources of renewable energy known so far, solar energy is considered to assume the role of sustainable future energy. Dye Sensitized Solar Cell (DSSC) is a low cost and ecofriendly technology for the conversion of sunlight into electricity [2]. Nanostructured Titanium dioxide (TiO 2) has attracted growing interest in DSSCs on account of its unique structure and properties [3]. The maximum power conversion efficiency in DSSCs reported so far 13% has been achieved by incorporating nanostructured Titanium dioxide (TiO2) [4]. The performance of these cells depend much on the shape and morphology of the TiO 2 photoanode. Usually, 3D-TiO2 nanostructures such as mesoporous nanoparticles, nanoflowers, nanospheres, and hierarchical nanostructures possess high surface area but they exhibit weak light scattering ability and lesser electron transport mobility which hinder the efficiency [5-8]. To improve the electron transport properties the integration of 1D-TiO2 nanostructures such as nanowires (NWs), nanotubes (NTs) which serve as direct pathways for electrons, provide enhanced transport rate and suppressed recombination rate have also been reported [9-11]. However 1D nanostructures suffer from low internal surface area, resulting in lower adsorption sites for sensitizer molecules and hence low light harvesting efficiency [12]. Recent discoveries showed that growing hierarchical structures on the top surfaces of 1D nanostructures improved light harvesting ability and internal surface area while keeping the direct and faster electron transport properties of 1D nanostructures [13, 14]. However the synthesis of hierarchical structures directly on 1D-TiO2 nanostructures remains a challenge. In this paper, we elucidate the synthesis and characterizations of highly porous and novel 1D-TiO2 Photoanode Nanoarchitecture (1D-TPA) with dandelion like TiO2 structures on the top surface as a MMSE Journal. Open Access www.mmse.xyz

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light scattering layer through single step solvothermal method for the first time without using any seed layer. The morphological and optical properties revealed that the proposed photoanode is a suitable candidate for achieving higher efficiencies in DSSCs. Preparation and Characterization. The nanoarchitecture was prepared on a seedless FTO (Fluorine doped Tin Oxide) substrate through one step solvothermal reaction. A homogenous solution was obtained by mixing and stirring 3mL of Ti containing precursor with a mixture solution containing 30mL conc. HCl, 10mL deionized water and 20mL ethanol. An ultrasonically cleaned FTO substrate with its conducting side facing down was placed inside a 100mL autoclave reactor containing the obtained homogenous solution and then solvothermal reaction was carried out at 150 oC for 12 hours. The sample was then annealed at 450oC for 30 minutes to obtain the desired TiO2 morphology. The crystallinity, crystal phases and crystallite size were determined using RICH SEIFERT X-ray Diffractometer equipped with CuKα irradiation (λ=0.154 nm). The morphology and elemental composition of the nanoarchitecture were observed using HITACHI S-4800 High Resolution Scanning Electron Microscope and Energy Dispersive X-ray Spectrometer respectively. The optical properties and band gap were determined using PERKIN ELMER (Lambda 35) UV/VIS Spectrometer. The electrical response of the photoanode to the visible spectrum of light was recorded using Kethley Picoammeter 6485-Photoconductivity studies. Results and Discussion. To identify the crystal phases of the synthesized photoanode, XRD measurements were conducted. In the obtained XRD pattern (figure 1) the characteristic peaks at 36.16o and 62.92o are well indexed with standard rutile TiO2 JCPDS card no.89-4920 while the peaks at 37.78oand 51.51o are due to the presence of SnO 2 in the conducting glass which matched well with standard FTO substrate JCPDS card no.41-1445 [15]. The above interpretation confirmed the presence of rutile TiO2 in the photoanode.

Fig. 1. XRD pattern of rutile TiO2 Nanoarchitecture. The maximum intensity of peak at the angle 62.92o (2θ) corresponding to the crystal plane (002) indicated that the 1D-TPA is well crystalized and oriented perpendicular to the FTO substrate. Since no other phases are identified, the XRD analysis also revealed that the nanoarchitecture is single MMSE Journal. Open Access www.mmse.xyz

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crystalline which is an essential condition for faster electron transport at the interfaces [16]. The average crystallite size is found to be approximately 19 nm using Scherrer’s equation [17].HRSEM observations showed that the synthesized 1D-TPA consists of DS over the vertically oriented NWs with high surface porosity where the length of the NWs array is about 2.5 µm. Figure 2(a) is the crosssectional view of the photoanode showing the vertical growth of the NWs from the substrate and Figure 2(b) shows the existence of nanowire aggregates in the photoanode. Figure 2(c) is the top view of the photoanode revealing the formation of DS on the top surface of the NW aggregates. Figure 2(d) shows the cross sectional view of an individual dandelion structure. The aggregation of NWs is due to the excess content of ethanol because high ethanol content reduces the absorption of Cl - ions on the (110) plane of the nanocrystals and promotes the increase in diameter of NWs [18]. Figure 3 is an EDAX spectrum of the photoanode which confirmed the presence of Ti and O whose weight and atomic percentages are on par with the standard TiO2 molecular data tabulated as inset.

b) 2d

(c)

(d)

Fig. 2. (a) Cross sectional view of the photoanode, (b) Existence of nanowire aggregates in the photoanode, (c) Top view of the photoanode, (d) Cross sectional view of an individual dandelion structure. Figure 4 (a) is a graph between wavelength of the incident light and the absorbance of the 1D-TPA. It is observed that there is an absorption in the UV region whereas no absorption is found in the visible region indicating that the 1D-TPA is highly transparent to the visible spectrum due to its wide bandgap. Another graph as shown in figure 4 (b) is plotted between wavelength of the incident light and the diffused reflectance of the 1D-TPA and it can be clearly observed that the entire visible wavelengths were diffusively reflected by the anode confirming the light scattering ability of the 1DTPA[19]. The enhanced light scattering ability is due to multiple back reflections of the incident light from the dandelion structures. This occurs when the wavelength of the incident radiation is comparable to the dimension of the dandelion structures. The energy of the incident light is plotted against the Kubelka-Mulk equation [20] as shown in figure 4 (c) to find the energy band gap of the photoanode and the value is found to be 2.93 eV which is equal to the theoretically calculated energy bandgap value of 2.95 eV using the energy equation E = hc/λ.

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Fig. 3. EDAX spectrum of the photoanode.

b) 4c

c) Fig. 4. (a) UV-VIS Absorption Spectrum, (b) UV-VIS Diffused reflectance Spectrum, (c) K-M analysis for finding bandgap.

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Fig. 5. Field dependent dark and photocurrents of the photoanode respectively. Field dependent dark and photocurrent measurements were taken on the basis of an earlier report [21] and the behavior of the 1D-TPAis shown in figure 5. The graph indicates the variation of current in the dark (Id) and visible light illuminated (Iph) photoanode with increase in applied electric field. It is observed that the photocurrent is greater than the dark current by about 2 folds for an applied field of 690 V cm-1. This is due to the remarkable liberation of electrons upon excitation by the visible light and efficient mobility of the generated carriers triggered by the applied field. Earlier reports showed that the dark and photocurrent values were obtained in microampere range for TiO 2 nanostructures [22] and the photocurrent value of the proposed photoanode is about 4 folds greater than that of the TiO2 nanorods based photoanode for an applied field of 400 V cm-1 [23]. The significant hike in the photocurrent values of the1D-TPA when compared with the earlier reports is because of unidirectional and faster transportation of the electrons through the 1D-TiO2 nanowire arrays. Summary. Numerous dandelion-like TiO2 scattering structures atop 1D-TiO2 nanowire aggregates were successfully prepared on FTO substrate via single step reaction for the first time targeting improved performance of the TiO2 based photoanodes for DSSCs. The incorporation of porous dandelion-like structures leads to increase in diffused reflectance which enhanced the light harvesting capability. The increase in the photocurrent shows that the proposed photoanode is conductive and photoactive as combining the advantages of nanowires and dandelion-like scattering structures. Therefore, the photoconductivity, surface porosity and light harvesting capacity of the photoanode are significantly improved by the new nanoarchitecture. Thus, the proposed photoanode provides a novel structure for improved light harvesting application incorporating 1D-TiO2 electron transporters. Acknowledgements. This research was supported in part by the Loyola College-Times of India Major Research Grants (6LCTOI14LIF002) and the authors wish to acknowledge the same. References [1] http://www.agci.org/library/presentations/about/presentation_details.php?recordID=16950. [2] B. O'Regan, M. Grätzel, Nature, 1991, 353, 737–740. DOI: 10.1038/353737a0. [3] M. Malekshahi Byranvand, A. Nemati Kharat, M.H. Bazargan, Nano-Micro Lett., 2012, 4(4), 253-266. DOI: 10.3786/nml.v4i4.p253-266. [4] S. Mathew, A. Yella, P.Gao, R. Humphry-Baker, B.F.E. Curchod, N. Ashari-Astani, I. Tavernelli, U. Rothlisberger, M.K. Nazeeruddin, M. Gratzel, Nat. Chem,2014, 6, 242-247.DOI: 10.1038/nchem.1861. MMSE Journal. Open Access www.mmse.xyz

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[5] T. J. Abodunrin, M. L. Akinyemi, A. O. Boyo & J. A. Olugbuyiro (2015). Photo Degradation in Dye-Sensitized Solar Cells. Mechanics, Materials Science & Engineering, Vol 1. doi:10.13140/RG.2.1.3208.0400 [6] J. Sahaya Selva Mary, P. Princy, J. Annai Joseph Steffy, P. Naveen Kumar, Neena Bachan, J. Merline Shyla, Int. J. Technical Research and Applications, 2016, 37, 60-64. [7] Zhao-Qian Li, Ya-Ping Que, Li-E Mo, Wang-Chao Chen, Yong Ding, Yan-Mei Ma, Ling Jiang, Linhua Hu, Songyuan Dai, ACS Appl. Mater. Interfaces, 2015, 7 (20), 10928–10934. DOI: 10.1021/acsami.5b02195. [8] Fang Shao, Jing Sun, Lian Gao, Songwang Yang, and Jianqiang Luo, ACS Appl. Mater. Interfaces, 2011, 3, 2148–2153. DOI: 10.1021/am200377g. [9] Sheng Meng, Jun Ren, EfthimiosKaxiras, Nano Lett., 2008, 8(10), 3266-3272. DOI: 10.1021/nl801644d [10] Ming La, Yunxiao Feng, Changdong Chen, Chengye Yang, Songtian Li,Int. J. Electrochem. Sci., 2015, 10, 1563 – 1573. DOI: 10.1.1.667.156. [11] Poulomi Roy, Steffen Berger, PatrikSchmuki, Angew .Chem. Int. Ed., 2011, 50, 2904–2939. DOI:10.1002/anie.201001374. [12] Bin Liu, S. Eray. J. Aydil. AM. CHEM. SOC., 2009, 131, 3985–3990.DOI: 10.1021/ja8078972. [13] Weixing Song, Yudong Gong, Jianjun Tian, Guozhong Cao, Huabo Zhao, Chunwen Sun, ACS Appl. Mater. Interfaces, 2016.8(21), 13418–13425. DOI: 10.1021/acsami.6b02887. [14] A. M. Bakhshayesh, S. S. Azadfar, N. Bakhshayesh, J. Mater Sci: Mater Electron, 2015, 26(12), 9808–9816. DOI: 10.1007/s10854-015-3653-4. [15] Yunxia Hu, Baoyuan Wang, Jieqiong Zhang, Tian Wang, Rong Liu, Jun Zhang, Xina Wang and Hao Wang, Nanoscale Research Letters, 2013, 8,222. DOI: 10.1186/1556-276X-8-222. [16] Wu-Qiang Wu, Bing-Xin Lei, Hua-Shang Rao, Yang-Fan Xu, Yu-Fen Wang, Cheng-Yong Su, Dai-Bin Kuang, Scientific Reports, 2013, 3, 1352. DOI: 10.1038/srep01352. [17] Leroy Alexander, Harold P.Klug, Journal of Applied Physics, 1950, 21, 137. DOI: 10.1063/1.1699612. [18] Hailiang Li, Qingjiang Yu, Yuewu Huang, Cuiling Yu, Ren-Zhi Li, Jinzhong Wang,FengyunGuo, Yong Zhang, Xitian Zhang, Peng Wang, Liancheng Zhao, ACS Appl. Mater. Interfaces, 2016, 8(21), 13384–13391. DOI: 10.1021/acsami.6b01508. [19] Zhao-Qian Li, Wang-Chao Chen, Fu-Ling Guo, Li-E Mo, Lin-Hua Hu & Song-Yuan Dai, Scientific Reports, 5, 14178. DOI: 10.1038/srep14178. [20] Harry G. Hecht, J. Research of the NBS-A. Physics and Chemistry, 1976, 80A (4). DOI: 10.6028/jres.080A.056. [21] Tenzin Tenkyong, Neena Bachan, J. Raja, P. Naveen Kumar, J. Merline Shyla, Materials Science-Poland, 2015, 33(4), 826-834. DOI 10.1515/msp-2015-0097. [22] A. Kumar, F. Xavier, J.M. Shyla, J. Mater. Sci., 2013, 48, 3700. DOI: 10.1007/s10853-0137167-2. [23] V. Chandrakala, J. Annai Joseph Steffy, NeenaB achan, W. Jothi Jeyarani, Tenzin Tenkyong, J. Merline Shyla, Acta Metall. Sin. (Engl. Lett.), 2016, 29, 457. DOI: 10.1007/s40195-016-0409-y. Cite the paper K.Pugazhendhi, W. Jothi Jeyarani, Tenzin Tenkyong, P. Naveen Kumar, B. Praveen, J. Merline Shyla (2017). Highly Porous and Novel 1D-TiO2 Nanoarchitecture with Light Harvesting Morphology for Photovoltaic Applications. Mechanics, Materials Science & Engineering, Vol 9. doi:10.2412/mmse.3.32.722

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Mechanical Engineering & Physics chapter

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Application of Quaternionic Matrices for Finite Turns’ Sequence Representation in Space Victor Kravets1,a, Tamila Kravets1, Olexiy Burov2 1 – National Mining University, Dnipro, Ukraine 2 – Jack Baskin School of Engineering, University of California-Santa Cruz, CA, USA a – prof.w.kravets@gmail.com DOI 10.2412/mmse.17.56.743 provided by Seo4U.link Keywords: monomial (1,0,-1)-matrices-(4x4), quaternionic matrices, Rodrigues’ formula, parameters of RodriguesHamilton, finite rotation. ABSTRACT. With the use of mathematical apparatus of monomial (1,0,-1)-matrices-(4x4), the Rodrigues’ vector formula describing the finite turn, is represented with quaternionic matrices. Two ways to deduct the Rodrigues’ formula in quaternionic matrices are provided: with the use of basic (1,0,-1)-matrices-(4x4), equivalent to the quaternion and conjugate quaternion; the vector and the opposite vector. It is demonstrated that the commutative product of two matrices(4x4) equivalent to the quaternion, determines the finite turn matrix, and the commutative product of two matrices-(4x4) equivalent to the conjugate quaternion determines the inverse matrix of the finite turn if the Rodrigues-Hamilton parameters are taken as quaternion components. With this use of mathematical induction method, the obtained results are generalized for the cases of arbitrary sequence of finite independent turns in space. The offered formula for representation of finite turns in space with quaternionic matrices is distinguished by its compactness and convenience for both analytic treatments and efficient computational algorithms development.

Introduction. The practical problems of inertial navigation, stabilization and moving objects' control stimulated growing interest in finite rotation theory. The key results of this theory are exposed in classic works by Gauss, Hamilton, Rodrigues, Cayley, Euler. The finite rotation theory got further development and appropriate mathematical description in fundamental works on analytic mechanics by A. Lur'ie [1], L.A. Pars [2], P. Appell [3], H. Goldstein [4] and others. In these works, parametric representation of rotation is examined, and quaternion components are used as parameters. An advantageous mathematical apparatus was broadly applied in the problems related to the aircrafts’ move control. As Boris Rauschenbach put it, quaternion is a fairly convenient and demonstrative description due to the dualism of quaternionic units which are, on the one hand, the basis vectors of the real three-dimensional space, and on the other — transformation function operators [5]. Quaternion algebra efficiency for inertial reference systems’ problems was shown by O. Ishlinsky [6], V. Branets, I. Shmyglevsky [7], S. Onyshenko [8] and others. In computational algorithms development, it was convenient to set equivalent quaternionic matrices. Some types of such matrices, under the name of quaternionic matrices, are provided by R. Bellman [9], A. Maltsev [10] and others [11, 12, 13]. Further, we apply the calculation of Monomial (1,0,-1)-matrices-(4х4) [14], which are equivalent to the quaternion and conjugate quaternion, vector and opposite vector, for the description of finite body rotation in the space.

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Formulation of the problem There are different ways to deduce a finite rotation formula (equations of Rodrigues). Below, the description of finite rotation is provided, on the ground of the introduced system of four unified matrices called quaternionic matrices [14]. The rotation of moving reference system OY1 Y2 Y3 related to the fixed reference system O X1 X 2 X 3 , the starting points of two systems being the same, is analyzed here (Fig. 1).



e x3 ey 3



 B

ey 2 e x2

e x1

e y1

Fig. 1. Pattern of finite rotation in space. The reference data has an orthonormal basis, which is called respectively e y i and ex i  i  1, 2,3  . It is considered that in the initial position the axis directions of the two systems coincide. The moving reference system is moved with  angle of rotation around a directional axis of rotation O A , and its points are invariant to the rotation. The direction O A is defined by a unit vector n : n  n1 ex1  n2 ex 2  n3 ex 3  n1 ey1  n2 ey 2  n3 ey 3 ,

Its components are invariant regarding the reviewed references and are bound by the condition n12  n22  n32  1 [15]. Positive rotation with an angle  180 corresponds to the right-handed screw rotation, the screw being twisted in towards the positive direction of axis of rotation. An arbitrary point В ( r ) fixed in the connected axes system, after a finite rotation gets a new position in the fixed axes system С (  ), and this position is to be found. Rodrigues’ formula. Applying the primitive operations of vector algebra, using the data from the picture (Fig. 2) we find: n  r  OA, OA   n  r  n ; n  r  ABs , DC  sin   n  r  ;

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AB  r  OA; AB  r   n  r  n ;

BD   AB;   1  cos .



s D

B r



 

Fig. 2. Vector chart of rotation. Hence:   r  BD  DC,

Or, in expanded form, using the set angle of rotation (  ), direction of rotation ( n ) and the initial position of the point ( r ) [15]:

  1  cos  n  n  r   cos  r  sin  n  r . Rodrigues’ formula applied to the basis vectors. With the rotation in space, the orthonormal basis of the moving axis is getting oriented differently regarding the orthonormal basis of fixed axes, according to the axes position on Fig. 3.

 ex 3

ey 3 О

ex1

ey 2 ex 2

e y1 Fig 3. Moving basis orientation regarding the fixed one with the rotation in space. MMSE Journal. Open Access www.mmse.xyz

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The coordinates of the arbitrary set point in space of moving − yi and fixed − xi  i  1, 2, 3 basis are connected with an obvious equity:

y1 ey1

ey 2

ey 3  y2  ex1 y3

ex 3  x2 . x3

ex 2

Here the basis vectors are bound by Rodrigues’ formula: e y i  1  cos   n n  ex i   cos  ex i  sin  n  ex i .

Specifically: with i  1 ey1  1  cos   n  n  ex1   cos  ex1  sin   n  ex1 

the following transformations are made, taking into consideration that:

n1 n  ex1

ex 2

ex 3  n2 ; n3

n  ex1  n1;

1 ex1  ex1

ex 2

ex 3  0 ; 0

0 n  ex1  ex1

ex 2

ex 3  n3 , n2

and also, coming to the trigonometric function of the half-argument: 1  cos   2sin 2 

cos   2 cos 2 

;

 1;

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sin   2sin 

 cos 

we obtain:

ey1  ex1

ex 2

ex 3





 [ n2  2n1 sin   0  2 cos 2   1  n3 2sin   cos  ]. 2 2 2 2 2

n2

Introducing the parameters of Rodrigues-Hamilton (Euler) [15]

a0  cos

 2

, a1  n1 sin

 2

, a2  n2 sin

 2

, a3  n3 sin

 2

fulfilling the condition of normalization a02  a12  a22  a32  1,

and also, taking into consideration that

n2  2n1 sin   a2 2a1 ; 2 2





0  2 cos   1  0 ( a02  a12  a22  a32 ); 2 2

0 n3 n2

2sin 

 cos 

0 2

 a3 , a2

we find a1 ey1  ex1

ex 2

ex 3  [ a2  2a1  0  (a  a  a  a )  a3 2a0 ]. a3 0 a2 2 0

2 1

2 2

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2 3

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In a similar way we obtain with i  2 :

a1 ey 2  ex1

ex 2

a3

ex 3  [ a2  2a2  1  (a  a  a  a )  0 2a0 ] a3 0 a1 2 0

2 1

2 2

2 3

and with i  3 :

a1 ey 3  ex1

ex 2

ex 3  [ a2  2a3  0  (a  a  a  a )  a1 2a0 ], a3 1 0 2 0

2 1

2 2

2 3

i. e.: 2a1  a02  a12  a22  a32  0 ey1  ex1

ex 2

ex 3  [

2a2 a1  0  2a3a0

];

2a3a1  0  2a2 a0

2a1a2  0  2a3a0 ey 2  ex1

ex 2

ex 3  [ 2a  a02  a12  a22  a32  0 ]; 2a3a2  0  2a1a0 2 1

2a1a3  0  2a2 a0 ey 3  ex1

ex 2

ex 3  [

2a1a3  0  2a1a0 ]. 2 2 2 2 2a  a0  a1  a2  a3  0 2 3

Hence, it follows: a02  a12  a22  a32

ey1

ey 2

ey 3  ex1

ex 2

ex 3  2  a2 a1  a3a0  2  a3 a1  a2 a0 

2  a1a2  a3a0  a a a a 2 0

2 1

2 2

2 3

2  a3 a1  a1a0 

2  a1a3  a2 a0 

2  a2 a3  a1a0  .

a02  a12  a22  a32

The first method of representing rotation in space by quaternionic matrices. Using the results of the monograph [14], we find that the matrix obtained here constitutes the kernel of the matrix Q, t equal to the multiplicative composition A  A of quaternionic matrices, that is

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1 0 A t A  0 0

0 a  a  a32  a22 2  a2 a1  a3 a0  2  a3 a1  a1a0  2 1

2 0

0 2  a1a2  a0 a3  a22  a32  a02  a12 2  a3 a2  a1a0 

0 2  a1a3  a0 a2  , 2  a2 a3  a0 a1  a32  a22  a12  a02

where

a0 a1 A a2 a3

a1 a0 a3 a2

a2 a3 a0 a1

a3 a2 t , A a1 a0

a0 a1 a2 a3

a1 a0 a3 a2

a2 a3 a0 a1

a3 a2 . a1 a0

Thus, we obtain

0 ey1

ey 2

ey 3  0 ex1

ex 2

ex3 A  t A

e y1

ey 2

ey 3

0 y1  0 y2 y3

ex1

ex 2

0 y A t A 1 y2 y3

ex 3

and, taking into consideration that

e y1

ey 2

ey 3

0 y1  0 y2 y3

ex1

ex 2

ex 3

0 x1 x2 x3

we find a concise formula for transforming the coordinates in moving and fixed axes system with the rotation in space, expressed via quaternionic matrices: A  t A  y0  x0 ,

where

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0 x y y0 ď&#x20AC;˝ 1 , x0 ď&#x20AC;˝ 1 . x2 y2 x3 y3

The second method of representing rotation in space by quaternionic matrices. It is to mention that the obtained result is found directly from Rodriguesâ&#x20AC;&#x2122; formula in coordinates

ď&#x192;Š ď Ş yi ď&#x192;Ş 2 sin 2 n ď&#x192;Ľ 2 i ď&#x20AC;˝1 ď&#x192;Ť

ď&#x20AC;¨ n ď&#x192;&#x2014; e ď&#x20AC;Š ď&#x20AC;Ť ď&#x192;Śď&#x192;§ď&#x192;¨ 2cos

ď Ş ď&#x192;ś ď Ş ď Ş ď&#x20AC; 1ď&#x192;ˇ exi ď&#x20AC;Ť 2 sin cos ď&#x20AC;¨ n ď&#x201A;´ exi ď&#x20AC;Š 2 ď&#x192;¸ 2 2

ď&#x192;š 3 ď&#x192;ş ď&#x20AC;˝ ď&#x192;Ľ xi exi , ď&#x192;ť i ď&#x20AC;˝1

with the use of vector and scalar multiplication products represented by quaternionic matrices which are provided in the monograph [14] 3

ď&#x192;Ľy i ď&#x20AC;˝1

2 sin 2

ď Ş 2

ď&#x192;Ľy i ď&#x20AC;˝1

ď&#x20AC;¨

n ď&#x20AC;¨ n ď&#x192;&#x2014; ex i ď&#x20AC;Š ď&#x201A;Ž ď&#x20AC;

2 sin

ď Ş 2

cos

ď&#x20AC;Šď&#x20AC;¨A

1 A0 ď&#x20AC;Ť A0t 2

ď Ş

ď&#x20AC;¨n ď&#x201A;´ e ď&#x20AC;Šď&#x201A;Ž a ď&#x20AC;¨ A 2 xi

ď&#x20AC;Š

ď&#x20AC;Ť A0t y0 ,

ď&#x20AC;Š

ď&#x20AC; A0t y0 ,

ď&#x192;Ś ď&#x192;ś 2 ď Ş ď&#x20AC; 1ď&#x192;ˇ ex i ď&#x201A;Ž a02 ď&#x20AC; a12 ď&#x20AC; a22 ď&#x20AC; a32 E0 ď&#x192;&#x2014; y0 , ď&#x192;§ 2 cos 2 ď&#x192;¨ ď&#x192;¸

ď&#x20AC;¨

ď&#x20AC;Š

i. e. ď&#x192;Š 1 ď&#x192;Şď&#x192;Ť ď&#x20AC; 2

ď&#x20AC;¨ A ď&#x20AC;Ť A ď&#x20AC;Š ď&#x20AC;¨ A ď&#x20AC;Ť A ď&#x20AC;Šď&#x20AC;Ťď&#x20AC;¨ a t 0

t 0

2 0

ď&#x20AC; a12 ď&#x20AC; a22 ď&#x20AC; a32

ď&#x20AC;ŠE

ď&#x20AC;¨ A ď&#x20AC; A ď&#x20AC;Šď&#x192;šď&#x192;şď&#x192;ť y

ď&#x20AC;Ť a0

t 0

ď&#x20AC;˝ x0 .

From the obtained matrix expression we proceed to the matrices equivalent to the vector A0 , A0 and t

t the opposite vector A 0 , A 0 to the matrices equivalent to quaternion A , A and conjugate quaternion

At , t At , their connection being expressed as: A ď&#x20AC;˝ a0 E0 ď&#x20AC;Ť A0 ,

At ď&#x20AC;˝ a0 E0 ď&#x20AC;Ť A0t ,

A ď&#x20AC;˝ a0 E0 ď&#x20AC;Ť t A0 ,

At ď&#x20AC;˝ a0 E0 ď&#x20AC;Ť t A0t .

. A0 ď&#x20AC;Ť A0t ď&#x20AC;˝ A ď&#x20AC; t A and,

It is easy to show that A0 ď&#x20AC; A0t ď&#x20AC;˝ A ď&#x20AC; At , t

đ??´0 + đ??´đ?&#x2018;Ą0 = 0,

A ď&#x20AC;Ť A ď&#x20AC;˝ 2 a0 E0 . t

Then, a0 ď&#x20AC;¨ A0 ď&#x20AC; A0t ď&#x20AC;Š ď&#x20AC;˝ a0 ď&#x20AC;¨ A ď&#x20AC; At ď&#x20AC;Š and ď&#x20AC;

ď&#x20AC;¨

1 A0 ď&#x20AC;Ť A0t 2

ď&#x20AC;Šď&#x20AC;¨A

ď&#x20AC;Š

ď&#x20AC;Ť A0t ď&#x20AC;˝ ď&#x20AC;

Here:

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ď&#x20AC;¨

ď&#x20AC;Š

1 A ď&#x192;&#x2014; A ď&#x20AC;Ť tA ď&#x192;&#x2014; tA ď&#x20AC;Ť A ď&#x192;&#x2014; tA . 2

then

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A  A  2 a0 A  E0 , t At A  2 a0 tA  E0 , that’s why A  A  t A  t A  2 a0

 A  A  2 E . t

Plugging these dependencies into the initial matrix expression, we obtain

A  t A  E0  a0  A  t A   2 a02 1 E0  a0  A  At  .









If a0 A  At  a0 A  t A  2 a02 E0 , then E0  2 a02 1 E0  2 a02 E0  0 .

After these transformations, the finite rotation formula, represented by quaternionic matrices, takes the concise form:

A  t A  y0  x0 . The quaternionic matrices product provided here has a commutative property

A t A  t A A

The quaternionic matrices examined here are formed according to Rodrigues-Hamilton parameters, which meet the condition of normalization, and thus we have the following equations:

At  t A  E0 , t At  A  E0 ,

A  At  E0 , A  t At  E0 .

Hence, it follows that t

A  A  y0  x0 .

The matrices At and A or A and At are orthogonal. It means that the matrices which are reciprocal to them can be found via transposition:

A  t

1



A   t

 A 1 t  A t 

 A A t

At ,

1



1



 A  A ,  A   A. t

It is to mention that det  At   1, det  tAt   1, det  A  1, det  tA  1 . MMSE Journal. Open Access www.mmse.xyz

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The deduction of the respective inverse matrix for the finite rotation is reduced to the transposition of the obtained matrix:

 A  A  A  t

At ,

 A  A  t

At  At ,

i.e., the alignment of the initial, fixed reference frame with the moving ones is performed with the use of the formula:

y0  At  t At  x0

y0  t At  At  x 0 .

In an expanded form, the obtained matrix formulas of transition from the moving axes to the fixed ones and vice versa respectively take the form:

0 a0 x1  a1  x2  a2 x3  a3

a1 a0 a3  a2

a2  a3 a0 a1

a3 a2  a1 a0

a0 a1 a2 a3

 a1 a0 a3  a2

 a2  a3 a0 a1

 a3 a2  a1 a0

0 y1 , y2 y3

0 a0 y1  a1  y2  a2 y3  a3

a1 a0  a3 a2

a2 a3 a0  a1

a3  a2 a1 a0

a0 a1 a2 a3

 a1 a0  a3 a2

 a2 a3 a0  a1

 a3  a2 a1 a0

0 x1 . x2 x3

Reducing the degree of matrices, these formulas might be put in a different form:

x1  a1 x2   a 2 x3  a3

a0 a3  a2

 a3 a0 a1

a2  a1 a0

 a1 a0 a3  a2

 a2  a3 a0 a1

 a3 a2  a1 a0

y1 y2 , y3

y1  a1 y 2   a2 y3  a3

a0  a3 a2

a3 a0  a1

 a2 a1 a0

 a1 a0  a3 a2

 a2 a3 a0  a1

 a3  a2 a1 a0

x1 x2 . x3

The symmetry distortion makes these formulas less attractive. Still, they might be more practical in calculations. Thus, if Rodrigues-Hamilton parameters are selected as the quaternion components, the commutative product of two matrices equivalent to the quaternions defines the finite rotation matrix, and the MMSE Journal. Open Access www.mmse.xyz

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commutative product of two matrices equivalent to the conjugate quaternion defines the inverse matrix. Addition of the sequence of independent spatial rotations in quaternionic matrices. On the ground of calculation of quaternion equivalent matrices [14], the concise formulas are found for the addition of the solid body finite spatial rotations’ sequence. The common algorithm is offered for adding the matrices of directional cosine of any independent rotations’ sets, which is applied in the dynamics of the navigated moving systems [16]. Addition of two independent rotations. Let us examine two successive solid body rotations, the body having a stable point (Fig. 4, a). With the first rotation, the arbitrary point of the solid body x0 is set into the position y0 , and with a second rotation − to the position determined by the vector

z0 .

Fig 4. The pattern for adding independent rotations of the solid body: a) two rotations; b) n rotations. The first movement is characterized by the rotation direction, which is defined by the unit vector n , and the preset rotation angle value  , and the second movement is defined by the unit vector m and the angle  . According to Euler's theorem [х], any movement of the solid body which has a fixed point, can be accomplished with one resulting rotation to the angle  around some axis k , which goes through the fixed point and moves the preset point of the body from the initial position x0 directly to the final position z0 . The problem is to define the characteristics of the resulting rotation k and  via the known characteristics n ,  , m , .

The first rotation is explicitly characterized by the set of Rodrigues-Hamilton parameters:

a0  cos

 2

a1  n1 sin

 2

a2  n2 sin

 2

The finite rotation matrix and the inverse matrix are represented respectively as:

A  tA or tA  A ,

At  tAt or tAt  At ,

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

a3  n3 sin . 2

Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954

and when the arbitrary point of the body from the initial position with the coordinates xi i  1, 2, 3 is moved to the intermediate position with coordinates yi i  1, 2, 3 , according to the formula y0  At  tAt  x0 ,

where

0 y y0  1 , y2 y3

0 x x0  1 . x2 x3

Similarly, for the second rotation we have:

b0  cos

 2

b1  m 1 sin

 2

b2  m 2 sin

 2

b3  m 3 sin

 2

and, respectively z0  B t  tB t  y0 ,

where zi i  1, 2, 3 − the coordinates of the finite position of the examined point of the body:

0 z z0  1 . z2 z3

With a help of an unknown set of Rodrigues-Hamilton parameters, characterizing the resulting rotation:

c0  cos

 2

c1  k1 sin

 2

c2  k 2 sin

 2

c3  k 3 sin

 2

and the respective finite rotation matrix С t  tC t or t C t  C t , which we want to find, the transformation of the coordinate axes OX1 X 2 X 3 is accomplished directly to the position OZ1Z 2 Z 3 by the similar formula: MMSE Journal. Open Access www.mmse.xyz

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z0 ď&#x20AC;˝ C t ď&#x192;&#x2014; tC t ď&#x192;&#x2014; x0 .

Excluding the coordinates of the intermediate position of the point đ?&#x2018;Ś0 , we obtain: z0 ď&#x20AC;˝ Bt ď&#x192;&#x2014;t Bt ď&#x192;&#x2014; At ď&#x192;&#x2014;t At ď&#x192;&#x2014; x0 .

Assigning the provided formulas, we find the finite rotation matrix: C t ď&#x192;&#x2014;t C t ď&#x20AC;˝ Bt ď&#x192;&#x2014;t Bt ď&#x192;&#x2014; At ď&#x192;&#x2014;t At .

Taking into consideration the commutative property of the examined matrices t Bt ď&#x192;&#x2014; At ď&#x20AC;˝ At ď&#x192;&#x2014;t Bt and supposing that the product of two similar matrices is the matrix of the same structure, we find: C t ď&#x20AC;˝ Bt ď&#x192;&#x2014; At ,

C t ď&#x20AC;˝t Bt ď&#x192;&#x2014;t At

or, as a result of transposition we obtain: t

C ď&#x20AC;˝t Aď&#x192;&#x2014;t B ,

C ď&#x20AC;˝ Aď&#x192;&#x2014; B .

Therefore, from the provided formulas we define the components of the resulting quaternion directly from the preset Rodrigues-Hamilton parameters:

c t ď&#x20AC;˝ b t ď&#x192;&#x2014; At

cď&#x20AC;˝t B t ď&#x192;&#x2014; a

cď&#x20AC;˝t A ď&#x192;&#x2014; b

ct ď&#x20AC;˝ at ď&#x192;&#x2014; B

Where a t , b t , c t â&#x2C6;&#x2019; row matrices ď&#x20AC;¨1ď&#x201A;´ 4ď&#x20AC;Š ; a , b , c â&#x2C6;&#x2019; column matrices ď&#x20AC;¨4ď&#x201A;´1ď&#x20AC;Š .

By these parameters, the unknown angle of the resulting rotation ď ą is found, as well as the directional cosines of the unit vector of the rotation axis ki i ď&#x20AC;˝ 1, 2, 3 :

cos

ď ą 2

ď&#x20AC;˝ c0 ,

k1 ď&#x20AC;˝

c1 , sinď ą 2

k2 ď&#x20AC;˝

c2 , sinď ą 2

k3 ď&#x20AC;˝

c3 . sinď ą 2

Addition for the sequence of the independent rotations. The formula entry represented here for adding two finite rotations in form of the introduced quaternionic matricesâ&#x20AC;&#x2122; product makes it possible to generalize the results by mathematical induction in case of three and more rotations (Fig. 1.4b). MMSE Journal. Open Access www.mmse.xyz

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Let us assume that there is a preset sequence n of rotations, with a corresponding set of predefined Rodrigues-Hamilton parameters. Then, two unified quaternionic matrices of the resulting rotation are defined by the product nof quaternionic matrices of the same structure, built on Rodrigues-Hamilton parameters in accordance with the accepted rotations’ sequence; and two unified quaternionic matrices of the resulting rotation, equivalent to the conjugate quaternion, are found by the product of the identical matrices in the inverse order:

R  A1  A2  A3    An , t

R  tA1  tA2  tA3    tAn ,

R t  Ant    A3t  A2t  A1t .

Rt  tAnt    tA3t  tA2t  tA1t ,

Thus, the examined pairs of the quaternionic matrices are connected by the transposition operation. Summary. With the use of mathematical apparatus of monomial 1,0, 1  matrices   4  4  , two approaches are offered for Rodrigues’ vector formula representation with quaternionic matrices. The finite turn’s matrix structure is defined as a commutative product of two matrices   4  4  , equivalent to quaternion and composed on Rodrigues-Hamilton parameters. The inverse matrix of finite turn is determined by the commutative product of two matrices   4  4  , equivalent to the conjugate quaternion. The results are generalized for the products of finite sequence: independent turns in space. The offered formula for representation of finite turns in space with four quaternionic matrices is distinguished by its compactness, mathematical description convenience and the possibility to develop efficient computational algorithms. References [1] Lur'e, A.I., Analytical mechanics, Springer Science & Business Media, 2002, 824 p. [2] Pars, L.A., A Treatise on analytical dynamics, Ox Bow Pr. Publ., 1981, 641 p. [3] Appell, P., Teoreticheskaya phizika [Traite de mecanique rationnelle], Moscow, Fizmatgiz Publ., Vol. 1, 1960, 515 p., Vol. 2, 1960, 487 p. (in Russian). [4] Goldstein, H., Classical mechanics, Addison-Wesley Publishing Company, 1980, 672 p. [5] Raushenbax, B.V., Tokar', E.N. Upravlenie orientatsiej kosmicheskix apparatov [The orientation of the spacecraft management], Moscow, Nauka Publ., 1974, 600 p. (in Russian). [6] Ishlinskij, A.Yu. Orientatsiya, giroskopy i inertsial'naya navigatsiya [Orientation, gyroscopes and inertial navigation], Moscow, Nauka Publ., 1976, 672 p. (in Russian). [7] Branets, V.N., Shmyglevskij, I.P. Primenenie kvaternionov v zadachax orientatsii tverdogo tela [The use of quaternions in problems of solid-state orientation], Moscow, Nauka Publ., 1973, 320 p. (in Russian). [8] Onischenko, S.M. Primenenie giperkompleksnyx chisel v teorii inertsial'noj navigatsii. Avtonomnye sistemy [The use of hyper complex numbers in the inertial navigation theory. Standalone systems], Kyiv, Naukova dumka Publ., 1983, 208 p. (in Russian). [9] Bellman, R., Introduction to Matrix Analysis, Second Edition, University of Southern California, 1997, 399 p. [10] Mal'tsev, A.I. Osnovy linejnoj algebry [Fundamentals of linear algebra], Moscow, Nauka Publ., 1970, 400 p. (in Russian).

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[11] Elliot, J.P., Dawber, P.G. Symmetry in physics, Vol. 1: Principles and Simple Applications, Oxford University Press, 1985, 302 p., Vol. 2: Further Applications, Oxford University Press, 1985, 298 p. [12] Berezin, A.V., Kurochkin, Yu.A., Tolkachev, E.A. Kvaterniony v relyativistskoj fizike [Quaternions in relativistic physics], Moscow, Editoreal Publ., 2003, 200 p. (in Russian). [13] Chelnokov, Yu.N. Kvaternionnye i bikvaternionnye modeli i metody mexaniki tverdogo tela i ix prilozheniya. Geometriya i kinematika dvizheniya [Quaternion and biquaternions models and methods of solid mechanics and their applications. The geometry and kinematics motion], Moscow, Fizmatgiz Publ., 2006, 512 p. (in Russian). [14] Kravets, V., Kravets, T., Burov, O. Monomial (1, 0, -1)-matrices-(4х4). Part 1. Application to the transfer in space. Lap Lambert Academic Publishing, Omni Scriptum GmbH&Co. KG., 2016, 137 p. ISBN: 978-3-330-01784-9. [15] Korn, G., Korn, T. Spravochnik po matematike dlya nauchnyh rabotnikov i inzhenerov [Mathematical Handbook for Scientists and Engineers], Moscow, Nauka Publ., 1984, 832 p. (in Russian). [16] Igdalov, I.M., Kuchma, L.D., Polyakov N.V., Sheptun Yu.D. Raketa kak ob’ekt upravleniya [Rocket as a control object], Dnipro, Art-Press Publ., 2004, 544 p. ISBN: 966-7985-81-4 [17] Victor Kravets, Tamila Kravets, Olexiy Burov (2017). Identities of Vector Algebra as Associative Properties of Multiplicative Compositions of Quaternion Matrices. Mechanics, Materials Science & Engineering, Vol 8. doi:10.2412/mmse.47.87.900

Cite the paper Victor Kravets, Tamila Kravets, Olexiy Burov (2017). Application of Quaternionic Matrices for Finite Turns’ Sequence Representation in Space. Mechanics, Materials Science & Engineering, Vol 9. doi:10.2412/mmse.17.56.743

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National Mining University is one of the oldest Ukrainian technical universities and the oldest one specialized in higher education for mining engineers. Founded in 1899 as Higher Mining Technical School, it has led to the establishment of all other universities in the region, including both traditional and specialized. After Ukraine regained its independence in 1991, the university was transformed into geotechnological higher educational institution under the name of State Mining Academy of Ukraine, where the attention is paid to management of resources and environmental protection, synchro-mining and post-mining processes, telecommunication and mechatronics, power engineering and information technologies, economics and finance. Finally, in 2002 the university was renamed to National Mining University, the name it still bears till today. Currently, it is one of the leading Ukrainian universities, consistently ranking in the Top 10 of all the universities in the country and retaining its standards for the quality of education. National Mining University proposes a wide number of bachelor and master programs for 8294 full-time students. Among the most successful international master programs are "International University of Resources" (jointly with Austrian Montan University and German Technical University "Freiberg Mining Academy") and "Master of Business Administration" (jointly with Franklin University, USA).

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