Optical Absorption Spectral Investigation of Dy2O3 Doped Zinc Strontium Bismuth Borate Glasses

Mechanics, Materials Science & Engineering, May 2017

ISSN 2412-5954

Optical Absorption Spectral Investigation of Dy2O3 Doped Zinc Strontium Bismuth Borate Glasses16 D. Kothandan1, K. Chandra Babu Naidu2, R. Jeevan Kumar2 1 Department of Science and Humanities,Sreenivasa Institute of Technology and Management Studies, Chittoor. (A.P).

India 2

Department of Physics, S.K. University, Anantapur (A.P), India DOI 10.2412/mmse.14.2.119 provided by Seo4U.link

Keywords: borate glasses, optical absorption spectrum, melt quenching method.

ABSTRACT. Borate glasses of (50-x) H3BO3-10SrF2-10Bi2O3-20ZnO-10SiO2-Mx (M = Dy2O3, x= 0.1) are prepared by melt quenching method. The resultant sample is characterized using X-ray diffract meter in order to confirm the amorphous nature. Further, the optical absorption spectrum is recorded to illustrate Judd-Ofelt (J-O) values and radiative parameters. The allowed transitions are also reported.

Introduction. Borate glasses pertaining rare earth metal oxides have significant applications for solid state, luminescent applications, laser hosts, lamp phosphors, broad band amplifiers, sensors, optical data storage devices and optical fiber communication systems [1]. Moreover, J-O theory is an important aspect to investigate the optical absorption spectrum. The J-O theory behind the optical properties of glass materials is explained as follows.

Judd-Ofelt theory According to J-O theory [2], [3] the intensity of the forbidden f f electric dipole transitions can arise from the admixture of configurations of opposite parity (e.g., ) into the 4fn configuration. It was considered that the odd part of the crystal-field potential is the perturbation for mixing states of different parity into the 4fn configuration. The experimental oscillator strength is given by (1)

The total oscillator strength of an absorption band is obtained from the expression

(2)

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/

MMSE Journal. Open Access www.mmse.xyz

95

Mechanics, Materials Science & Engineering, May 2017

ISSN 2412-5954

where n is the refractive index of the medium, m is the electron mass, is the wave number of the transition in cm-1, h J + 1) is the degeneracy of the ground state is the Lorentz local field correction which accounts for dipole-dipole correction.

The intensitie3s of the magnetic dipole transitions which are weak are relatively independent of the surrounding Ln ions. Therefore the experimental oscillator strengths are almost equal to the electric dipole oscillator strengths.

(3) Hence the experimental oscillator strengths can be equated to the calculated oscillator strengths.

(4)

The experimental oscillator strengths are evaluated from the obtained spectra and used to find the JO intensity parameters intensity parameters ( = 2, 4 and 6) by least square fit. The quality of the fit is determined by the rms deviations between the measured and calculated oscillator strengths.

The intensity of f f transitions in rare earth complexes is ligand dependent. Hence many authors tried to correlate the intensity parameters with the chemical nature of ion-ligand bond, with the properties of the ligand itself or with the structure of the complex. 2 depend on the asymmetry of the rare earth ligand field. 2 depends on the short-range effects i.e., the covalency of the ligand field.

It depends on the structural changes in the vicinity of the lanthanide ion. 4 and 6 follow the same trend and mainly depend upon long-range effects. These parameters are related to the bulk properties of the host material and the indicators of viscosity of the rare earth doped glasses. The spectroscopic quality factor ( ), which is useful for predicting the stimulated emission in any laser active medium and is given by

(4)

Radiative properties The radiative properties of excited states of RE3+ ion are predicted by the J-O parameters using refractive index. For the transition the radiative transition probability can be obtained from the equation:

(5)

MMSE Journal. Open Access www.mmse.xyz

96

Mechanics, Materials Science & Engineering, May 2017

ISSN 2412-5954

The total radiative transition probability is given by

(6)

The radiative lifetime of an excited state is obtained from the expression

(7) (8)

The peak stimulated emission cross-section, obtained from the equation

p

( J,

J and

(9) Where peak wave length of the transition and is its effective line width. The large values of stimulated emission cross-sections indicate the good lasing transitions. A brief introduction to theoretical models of J-O (Judd-Ofelt) theory to predict the radiative properties such as radiative transition probabilities (AT R P) have been discussed in this study.

Experimental Procedure The glasses of general formula (50-x) H3BO3-10SrF2-10Bi2O3-20ZnO-10SiO2-Mx (M = Dy2O3 x = 0.1 have been prepared by mixing them in appropriate quantity with the help of digital electronic balance. The chemicals of 99.9 % purity (Sigma Aldrich) are taken. All these compositions are mixed together and stirred in a porcelain crucible. The mixture is melted by placing it in a programmable furnace 11000C for 30min. The glass samples are taken out from the furnace and pour onto different metal plates. The plate is again annealed for 3000C and as the result the glasses are obtained having transparent, pure and amorphous in nature. The samples are characterized by using XRD (Bruker, Cu e structure and absorption spectrum.

Result and Discussions The recorded XRD profile of Dy3+ doped zinc strontium bismuth borate glass (ZnSrBiB) is shown in Fig. 1 [4]. It confirmed the amorphous nature without exhibiting any single or polycrystalline phases.

MMSE Journal. Open Access www.mmse.xyz

97

Mechanics, Materials Science & Engineering, May 2017

ISSN 2412-5954

Fig. 1. The optical absorption spectra of Dy3+ doped ZSBiB glasses.

Table 1. Experimental (fexp) & calculated (fcal) spectral intensities of Dy3+ doped ZSBiB glasses.

Judd-Ofelt (J-O) Values of Dy3+ doped BiZnSr borate glasses The experimental and calculated J-O spectral intensities are obtained for all the absorption bands of Dy3+ ions in all the glass matrices. The experimental and calculated spectral intensities along with the rms deviations in all the glass matrices are presented in Table.1. It is observed that there is a good agreement between experimental and calculated values for all the transitions. Among these glass matrices the higher spectral intensities are observed for 6F5/2 transition. This indicates that high asymmetry [5-8] achieved for all the glass matrices in the present work. The J-O intensity parameters 2

4

6

described in chapter I and the data is presented in Table.1. In order of magnitude of J-O intensity 3+ 2 4 6 for all the Dy based glass matrices of the present work.

Radiative parameters The radiative parameters of samarium doped glasses are estimated with the help of J-O theory [9].

The radiative transition probability (Arad) of different transition of Dy3+ R) and radiative life time [10] of the excited states 6H15/2, 6H13/2 and 6H11/2. These values are tabulated in Table 2. High branching ratio of 0.73 is obtained for the excited state of 6H13/2.

MMSE Journal. Open Access www.mmse.xyz

98

Mechanics, Materials Science & Engineering, May 2017

ISSN 2412-5954

Table 2. Radiative parameters of Dy3+ doped ZnSrBi borate glass.

S.No

Transition

Radiative transition Probability

Branching ratio

1

6

H15/2

132

0.08

2

6

H13/2

1214

0.73

3

6

H11/2

317

0.19

Radiative lifetime 0.525 ms Summary. Judd-Ofelt analysis has been successfully applied to evaluate the J-O experimental (Fexp), calculated (Fcal) spectral intensities, transitions of Dy2 O3 is discussed. From these J-O parameters radiative properties such as radiative transition probabilities (AT), radiative life times ( R), experimental branching ratio ( ) and peak stimulated emission cross-section ( P) are calculated at room temperature (RT). In case of Dy2O3 doped glasses the experimental (Fexp), calculated (Fcal) spectral intensities have been discussed for the energy levels 4F3/2 , 4F5/2 , 6F7/2, 6F9/2, 6F11/2 and 4H11/2. The calculated radiative parameters are presented for various transitions of 6H15/2, 6H13/2 and 6H15/2.

Acknowledgements. Authors express their thanks to Department of physics, Sri Krishnadevaraya University, Anantapuramu, for providing laboratory facilities to carry out the present research work.

The financial support rendered by the UGC under SAP [No.F.530/8/DRS/2010 (SAP- I)] and Department of Science and Technology under FIST [SR/FST/PSI-116/2007], New Delhi, are gratefully acknowledged.

References [1] M. Venkateswarlu, B. H. Rudramadevi, 2015, International Journal of ChemTech Research Vol.7, No.2, pp. 607-612.

[2] J-o A. A. Bhaghat, E. E. Shaisha, A. I. Sabry, 1987, J. Master, Sci. Vol. 22, p. 3323.

[3] D. Kothandan, PhD. thesis S.K.University, Anantapur, A.P, 2016.

[4] D. Kothandan and R. Jeevan Kumar, 2016, Investigations on Electrical and Thermal Properties of Rare Earth Doped BiZnSr Borate Glasses, Journal of The Australian Ceramic Society Volume 52, 156 166.

[5] K.Venkata Rao, PhD. thesis, S.V.University, Tirupathi, 2011.

[6] E. W. Omen, A. M. A. Van Dongen, 1989 J. Non-Cryst, Solids Vol. 111, p. 205.

[7] C.Rudowiez, P. Guntek, M. Kabowik, 2011, Opt. Master Vol. 33, p.1557.

[8] C. Gautam, A. Kumar Yadav and A. K. Singh, 2012, A review on infrared spectroscopy of borate glasses with effects of different additives, ISRN Ceramics Volume 2012, DOI 10.5402/2012/428497.

[9] B. Karthikeyan, 2006, FTIR spectral analysis on heavy metal borate glasses, Modern Physics Letters B, Vol.20 Issue 10, DOI 10.1142/S0217984906010688.

[10] S. G. Motke, S. P. Yawale, S. S. Yawale, 2002, Infrared spectra of zinc doped lead borate glasses, Bull. Mater. Sci. Vol. 25, No.1, pp 75-78, DOI 10.1007/BF02704599

MMSE Journal. Open Access www.mmse.xyz

99