Landau expansion parameters for BaTiO3
Landau expansion parameters for BaTiO3
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DOI：
10.1063/1.4838456
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发表时间：
2013-12
影响因子：
3.2
通讯作者：
Xiaoyan Lu;Hui Li;W. Cao
中科院分区：
文献类型：
--
作者：
Xiaoyan Lu;Hui Li;W. Cao
自由能以序参量表示的6阶泰勒展开式已被普遍接受来描述一阶结构相变。近年来，为了解释BaTiO_3单晶中观察到的两个分支的介电环，一些研究者加入了8阶项。我们表明，如果在丰富的信息，场致相变的探索，终止于6阶的朗道自由能是足够的，以适应实验观察。利用居里温度以上铁电介质双回路的典型特性，可以高精度地确定随温度变化的膨胀系数。
The 6th order Taylor expansion of the free energy in terms of the order parameter has been generally accepted to describe first order structural phase transitions. In recently years, some researchers added the 8th order terms in order to explain the two branches in dielectric loops observed in the BaTiO3 single crystal. We show that the Landau free energy terminated at the 6th orders is sufficient to fit the experimental observations if the rich information in the field-induced phase transitions is explored. By using the typical characteristics of ferroelectric and dielectric double loops above the Curie temperature Tc, the temperature-dependent expansion coefficients can be determined with high accuracy.