Structural and electrical properties of a new lead free tungsten bronze ferroelectric ceramics Na₂Ba₂Eu₂W₂Ti₄Nb₄O₃₀

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• 作者：S. Saparjya ; S. Behera ; B. Behera…
• 刊名：Journal of Materials Science: Materials in Electronics
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：28
• 期：4
• 页码：3843-3850
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Optical and Electronic Materials; Characterization and Evaluation of Materials;
• 出版者：Springer US
• ISSN：1573-482X
• 卷排序：28

文摘

Lead free polycrystalline sample of Na₂Ba₂Eu₂W₂Ti₄Nb₄O₃₀ was prepared using high-temperature (~1200 °C) solid-state reaction technique. Room temperature X-ray structural analysis confirms the formation of single phase compound in orthorhombic crystal structure. The surface morphology of the sintered sample recorded by scanning electron microscope exhibits a uniform grain distribution. The compositional characterization of the sample was carried out using energy dispersive spectroscopy. Detailed studies of the nature of variation of dielectric constant and tangent loss with temperature indicate possible existence of ferroelectricity in the material. The temperature dependence of electrical parameters (impedance, modulus, etc.) of the material exhibits a strong correlation of its micro-structure (i.e., bulk, grain boundary, etc.) with the electrical parameters. The hopping mechanism for electrical transport properties of the system with non-exponential type of conductivity relaxation was suggested on the basis of electrical modulus analysis. The frequency dependence of ac conductivity suggests that the material obeys Jonscher’s universal power law. The temperature dependence of dc conductivity of the compound follows Arrhenius equation. Ferroelectric property of the compound was confirmed from polarization (hysteresis) study.