Dielectric Relaxation in Complex Perovskite Oxide Sr(Gd<sub>0.5</sub>Nb<sub>0.5</sub>)O<sub>3</sub>
Dielectric Relaxation in Complex Perovskite Oxide Sr(Gd<sub>0.5</sub>Nb<sub>0.5</sub>)O<sub>3</sub>作者机构：Department of Physics Bose Institute Kolkata India University Department of Physics T. M. Bhagalpur University Bhagalpur India University Department of Physics V. K. S. University Ara India
出 版 物：《Materials Sciences and Applications》 (材料科学与应用期刊（英文）)
年 卷 期：2012年第3卷第6期
页 面：369-376页
主 题：Dielectrics Perovskite Oxides X-Ray Diffraction Scanning Electron Micrograph
摘 要：The complex perovskite oxide a strontium gadolinium niobate (SGN) synthesized by solid-state reaction technique has single phase with tetragonal structure. X-ray diffraction (XRD) technique and scanning electron microscopy (SEM) were used to study the structural and microstructural properties of the ceramics, respectively. The XRD patterns of SGN at room temperature show a tetragonal structure. Studies of the dielectric constant and dielectric loss of compound as a function of frequency (50 Hz to 1 MHz) at room temperature, and as a function of temperature (60°C to 420°C) indicate polydispersive nature of the material. The logarithmic angular frequency dependence of the loss peak is found to obey the Arrhenius law with activation energy ~0.18 eV. The small value of activation energy of the compound (~0.18 eV) can be explained by mixed ionic-polaronic conductivity mechanism. The grain size of the pellet sample was found to be 1.92 μm. The frequency-dependant electrical data are analyzed in the framework of conductivity and electric modulus formalisms. The complex plane impedance plot shows the grain boundary contribution for higher value of dielectric constant in the law frequency region.
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