Two Different Mechanisms of the Curie-Weiss Dielectric Susceptibility in Ferroelectrics
Two Different Mechanisms of the Curie-Weiss Dielectric Susceptibility in Ferroelectrics
复制标题
铁电体居里-维斯介电常数的两种不同机制
DOI：
10.1143/jpsj.57.4275
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发表时间：
1988
影响因子：
1.7
通讯作者：
M. Tokunaga
中科院分区：
文献类型：
--
作者：
M. Tokunaga
在自洽声子近似下，铁电体介电常数χ的Curie-Weiss定律是由两种不同的机制导出的：一种是偶极子间的关联增加，它与静电相互作用D的大小有关;另一种是软模的均方振幅的减小，这导致居里-外斯定律通过单个磁化率的增加率1/t0与有效“偶极矩”的减小。数值计算了χ对温度的依赖关系，研究了居里常数对t0和D的依赖关系。从铁电体的实验数据中计算了顺电磁矩与饱和磁矩的比值。位移型铁电体中这些比值的偏离用t0来解释。
The Curie-Weiss law of the dielectric susceptibility χ in ferroelectrics is shown to be derived from two different mechanisms in the self-consistent phonon approximation: One is the increase in the correlation between dipoles which is related to the magnitude of the electrostatic interaction D . The other is the decrease in the mean square amplitude of the soft mode, which leads to the Curie-Weiss law through the rate of increase 1/ t 0 of an individual susceptibility with the decreasing effective “dipole moment”. The dependence of χ on temperature has been numerically computed to investigate the dependence of the Curie constant on t 0 and D . The ratios of the paraelectric moment to the saturation moment have been evaluated from available experimental data in ferroelectrics. Deviations of these ratios from unity in displacive type ferroelectrics are explained in terms of t 0 .