Mechanics, Materials Science & Engineering, May 2017 – ISSN 2412-5954
Dielectric Loss Behavior of SrxZn1-xMnTiO5 (x = 0.1 to 0.9) Ceramics 18 M. Maddaiah1,a, T. Sofi Sarmash1, T. Vidya Sagar1, T. Subbarao1 1 – Ceramic Composite Lab, Dept. of Physics, S. K University, Anantapuramu, A.P., India a – venkateswararaoikp@gmail.com DOI 10.2412/mmse.66.93.675 provided by Seo4U.link
Keywords: ceramics, titanate, dielectric loss, absorbers, microwave devices.
ABSTRACT. SrxZn1-xMnTiO5 (x = 0.1 to 0.9) ceramic samples were prepared by conventional solid state reaction technique. The mixed powder was calcined in the temperature range of 1050-1150oC for 10 hours. Further, the pellets were sintered finally in the temperature range 1150-1250oC for 2 hours in a crucible. The samples are characterized for dielectric properties. Especially, the variation of dielectric loss as a function of temperature and composition is discussed. The achieved results show that at room temperature all the samples reveal the low loss values which are suitable for low noise and microwave device applications. On the other hand, at high temperature all the samples perform the absorber behavior as they express high dielectric loss values.
Introduction. Strontium manganese titanate compound is unique material revealing antiferrodistortive elastic property, polar dielectric and spin glass magnetic behavior simultaneously [1]. So far there is no through studies on the synthesis of SrxZn1-xMnTiO5 (x=0.1 to 0.9) by solid state diffusion method and characterization by structural, dielectric, electrical and thermal properties. The substitution of zinc and manganese ions to from (Zn, Mn) TiO3 solid solution, is adopted to improve the thermal stability and dielectric properties. Strontium titanate-based ceramics were widely used to fabricate some electronic components, such as grain boundary layer capacitors (GBLC) was fabricated [1], it has been shown to have a great many merits, such as high-capacitance, low dielectric loss, and small size for low-voltage circuitry [2-7]. This requires a dielectric material with both high relative tunability nr (E) = [έ (0) - έ (E)]/έ(0) (where έ (0) is the dielectric constant at zero field, and έ (E) is the dielectric constant under applied field E), and very low dielectric loss at microwave frequencies. High tenability offers a capability for broad-range adjustment of the working frequencies, and low loss provides low noise, high selectivity and compatibility with cryogenic electronics. Zinc titanate (ZnTiO3) has hexagonal structure of dielectric materials for microwave applications such as mobile telephones and satellite communication systems. High performance with low loss and stable temperature coefficient of resonance frequency (τf) is basic requirement of dielectric. Alexander Tkach, Paula M. Vilarinho and Andrei L. Kholkin [8] studied the microstructure–dielectric tunability relationship in Mn-doped strontium titanate ceramic samples were prepared by the conventional mixed oxide method. The grain size was found to differ marked between Sr1-xMnxTiO3 (variation from 20 to35 µm) and SrT1-yMnyO3 ceramics (much finer grains from 0.6 to 0.8 µm) were observed), without clear dependence on Mn content. In the recent literature Naidu et al. [2], [9], [10], [11], Kumar et al. [12] and Maddaiah et al. [1], [13] investigated the effect of various elements (La, Mg, Mn, Cu, Zn & Bi) on electrical properties such as dielectric constant, loss, thermoelectric power, ac-conductivity and dc-conductivity of SrTiO3 electro ceramic material. These researchers reported that the Cu-doped SrTiO3 shows highest dielectric constant at room temperature (RT) [9]. In addition, several researchers showed the addition of zinc improves the loss of ceramic materials [14], [15]. © 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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Mechanics, Materials Science & Engineering, May 2017 – ISSN 2412-5954
Hence an attempt is made to study the dielectric properties for achieving high loss so as to provide dielectric absorbers. Sample Preparation. SrxZn1-xMnTiO5 (x=0.1 to 0.9) ceramic samples were prepared by conventional solid state reaction technique. High Purity chemicals of MnCO3, ZnO, TiO2 and SrCO3, (all from Aldrich of 99.9%) were used as the raw materials. These powders were mixed thoroughly and ground to obtain fine powders. The powders were uniaxially pressed initially into a cylindrical disc of 1.2 cm in diameter and about 2 mm of thickness. This mixed powder was calcined in the temperature range of 1050-1150oC for 10 hours. The powders were uniaxially pressed initially into a cylindrical disc of 1.2 cm in diameter and about 2 mm of thickness at a pressure of 10 tons. These discs were sintered finally in the temperature range 1150-1250oC for 2 hours in a crucible. Further the characterization is made using various LCR meter. Results and Discussion.The structural, morphological properties and the variation of dielectric constant as a function of temperature are reported in the authors’ previous work [1]. Figure 1-5 depict the Dielectric loss versus temperature of SrxZn1-xMnTiO5 (x=0.1-0.9). From all these plots the dielectric loss increases with increase of temperature but it decreases with increase of frequency. This is a usual dielectric behavior as reported in the literature [16]. From all the plots the dielectric loss were increased with increase of the temperature and decreased with the increase of the frequency because of the Sr-composition in the sample which might be caused due to the increase of density. The higher value of tan δ at high temperatures may be due to transport of ions with higher thermal energy. The sharp increase in tan δ may be due to the scattering of thermally activated charge carriers and some defects in the samples. At higher temperature the conductivity begins to dominate, which in turn is responsible for the rise in tan δ that is associated with the loss by conduction i.e., tan δ. Also at high temperature (paraelectric phase) the contribution of ferroelectric domain walls to tan δ decreases, which is responsible for the rise in tan δ. These types of dielectric behavior were also observed in some similar types of compounds. The increase of the tan δ peak in the ferroelectric region is probably due to the increase in the domain populations instead of the grain sizes. Orientation of the electric and elastic dipoles results in domain-wall pinning and thus a reduction of the dissipation in the ferroelectric state. On the other hand, the presence of oxygen vacancies and defects will cause larger losses at higher temperatures. These kind of larger loss values are useful for absorber applications [17], [18].
Fig. 1. Shows the Dielectric loss Vs Temperature (K) of Sr01Zn0.9MnTiO5 & Sr0.2Zn0.8MnTiO5.
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Mechanics, Materials Science & Engineering, May 2017 – ISSN 2412-5954
Fig. 2. Shows the Dielectric loss Vs Temperature (K) of Sr0.3Zn0.7MnTiO5 & Sr0.4Zn0.6MnTiO5.
Fig.3. Shows the Dielectric loss versus Temperature (K) of Sr0.5Zn0.5MnTiO5 & Sr0.6Zn0.4MnTiO5.
Fig. 4. Shows the Dielectric loss versus Temperature (K) of Sr0.7Zn0.3MnTiO5 & Sr0.8Zn0.2MnTiO5.
Fig. 5. Shows the Dielectric loss Vs Temperature (K) Sr0.9Zn0.1MnTiO5.
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Mechanics, Materials Science & Engineering, May 2017 – ISSN 2412-5954
Summary. The strontium manganese zinc titanate ceramic materials were synthesized via conventional solid state reaction method. The obtained low loss values at room temperature and high values at high temperature provide low noise device and dielectric absorber applications. References [1] 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) 155159. [2] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, P. Sreenivasula Reddy, D. Jhansi Rani, T. Subbarao, Journal of The Australian Ceramic Society Volume 52(1), 2016, pp. 95 – 101. [3] E. Elayaperumal, Girish M. Joshi, M. Malathi, International Journal of ChemTech Research Vol. 7, (2014-2015), 212-217. [4] S. Prathap, K. Chandra Babu Naidu and W. Madhuri, AIP Conference Proceedings, 1731, 030019 (2016); DOI 10.1063/1.4947624. [5] D. Kothandan, R. Jeevan Kumar, Journal of the Australian Ceramic Society, 52 (1), (2016)156166. [6] M. Vasubabu, C. Suresh Babu, R. Jeevan Kumar, International Journal of ChemTech Research Vol. 9, (2016), 80-84. [7] Budigi Lokesh, S. Kaleemulla, N. Madhusudhana Rao, International Journal of ChemTech Research 6 (2014) 1929-1932. [8] Alexander Tkach, Paula M. Vilarinho and Andrei L. Kholkin Acta Materialia, 53 (2005), 5061. [9] K. Chandra Babu Naidu, T. Sofi Sarmash, M.Maddaiah, V.Narasimha Reddy and T.Subbarao, AIP Conference Proceedings 1665, 040001 (2015); DOI 10.1063/1.4917614. [10] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, P. Sreenivasula Reddy, D. Jhansi Rani, T. Subbarao, Journal of The Australian Ceramic Society Volume 52(1), 2016, 95 – 101. [11] 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. [12] S. Anil Kumar, K. Chandra Babu Naidu, International Journal of ChemTech Research, 9 (2016), 58-63. [13] M.Maddaiah, K.Chandra Babu Naidu, D. Jhansi Rani, T. Subbarao, Journal of Ovonic Research Vol. 11, (2015), 99 – 106. [14] Chandra Babu Naidu K., Madhuri W, Materials Chemistry and Physics, 181 (2016), 432-443. [15] K. Chandra Babu Naidu, W. Madhuri, International Journal of Applied Ceramic Technology, 13 (2016), 1030-1035. [16] S. Prathap, K. Chandra Babu Naidu, and W. Madhuri, AIP Conference Proceedings 1731, 030019 (2016); DOI 10.1063/1.4947624. [17] V. Narasimha Reddy, K. Chandra Babu Naidu, T. Subba Rao, Journal of Ovonic Research 12 (2016), 185- 191. [18] K. Chandra Babu Naidu, W. Madhuri, Journal of Magnetism and Magnetic Materials, 420 (2016), 109–116. Cite the paper M. Maddaiah, T. Sofi Sarmash, T. Vidya Sagar, T. Subbarao, (2017). Dielectric Loss Behavior of SrxZn1xMnTiO5 (x = 0.1 to 0.9) Ceramics. Mechanics, Materials Science & Engineering, Vol 9. Doi
10.2412/mmse.66.93.675
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