Dielectric relaxation in bismuth layer-structured BaBi4Ti4O15 ferroelectric ceramics
Dielectric relaxation in bismuth layer-structured BaBi4Ti4O15 ferroelectric ceramics
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DOI：
10.1016/j.cap.2010.07.008
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发表时间：
2011-03-01
影响因子：
2.4
通讯作者：
Varma, K. B. R.
中科院分区：
文献类型：
--
作者：
Kumar, Sunil;Varma, K. B. R.
研究了BaBi4Ti4O15陶瓷在不同温度(30℃~470℃)下的介电性能随频率(10(2)~10(6)Hz)的变化。用Cole-Cole方程对复阻抗数据进行拟合，得到了两种不同的导电机理。晶界和晶界的电阻率与激活能之间的关系符合Arrhenius定律：T-m以下的E-g类似于1.12 eV，T-m以上的E-g类似于0.70 eV；T-m以下的E-Gb类似于0.93 eV，T-m以上的E-Gb类似于0.71 eV。用复阻抗虚部Z‘(Omega)和模数M’‘(Omega)提取的驰豫时间也符合Arrhenius定律，并在相变温度附近出现反常。用跳跃松弛模型解释了电导率与频率的关系，并符合双幂定律。(C)2010爱思唯尔B.V.保留所有权利。
The dielectric properties of BaBi4Ti4O15 ceramics were investigated as a function of frequency (10(2)-10(6) Hz) at various temperatures (30 degrees C-470 degrees C), covering the phase transition temperature. Two different conduction mechanisms were obtained by fitting the complex impedance data to Cole-Cole equation. The grain and grain boundary resistivities were found to follow the Arrhenius law associated with activation energies: E-g similar to 1.12 eV below T-m and E-g similar to 0.70 eV above T-m for the grain conduction; and E-gb similar to 0.93 eV below T-m and E-gb similar to 0.71 eV above T-m for the grain boundary conduction. Relaxation times extracted using imaginary part of complex impedance Z ''(omega) and modulus M ''(omega) were also found to follow the Arrhenius law and showed an anomaly around the phase transition temperature. The frequency dependence of conductivity was interpreted in terms of the jump relaxation model and was fitted to the double power law. (C) 2010 Elsevier B. V. All rights reserved.