The structural and electric properties of the perovskite system BaTiO₃–Ba(Fe_1/2Ta_1/2)O₃

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• 作者：Li ; Guobao ; Liu ; Shixiang ; Liao ; Fuhui ; Tian ; Shujian ; Jing ; Xiping ; Lin ; Jianhua ; Uesu ; Yoshiaki ; et. al.
• 关键词：Relaxor ; Structure ; Space group P3m1 ; Perovskite ; Conductivity and dielectric property ; Barium iron tantalum oxide
• 刊名：Journal of Solid State Chemistry
• 出版年：2004
• 出版时间：April - May, 2004
• 年：2004
• 卷：177
• 期：4-5
• 页码：1695-1703
• 全文大小：534 K

文摘

Compounds in the pseudo-binary BaTiO₃–Ba(Fe_1/2Ta_1/2)O₃ system have been synthesized at 1500°C in air and characterized by X-ray and electron diffraction as well as impedance analysis and Mössbauer spectroscopy. The symmetry of Ba(Fe_1/2Ta_1/2)O₃ is found to be trigonal with the space group P3m1. Two solid solutions exist in the BaTi_1−xFe_x/1Ta_x/1O₃ system at room temperature. The first (SS1) is in the composition range 0≤x≤0.07 and is tetragonal, P4mm, while the second broader solid solution, (SS2) 0.12≤x≤1, is trigonal and has the space group P3m1. The conductivity becomes higher with reduced amount of Ti in the structure. The activation energy of conductivity differs between the two solid solutions, 0.80eV for SS1 and 0.30eV for SS2, which indicates different mechanisms. The maximum of the real part of the permittivity recorded for compounds in SS1 decreases towards room temperature with increasing amount of Fe/Ta doping and a high dielectric constant of around 7000 is found for BaTi_0.94Fe_0.03Ta_0.03O₃.