SURFACE EFFECTS ON PHASE-TRANSITIONS IN FERROELECTRICS AND DIPOLAR MAGNETS
SURFACE EFFECTS ON PHASE-TRANSITIONS IN FERROELECTRICS AND DIPOLAR MAGNETS
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DOI：
10.1103/physrevb.20.1065
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发表时间：
1979-01-01
影响因子：
3.7
通讯作者：
BINDER, K
中科院分区：
文献类型：
--
作者：
KRETSCHMER, R;BINDER, K
本文提出了一种描述铁电薄膜在金属电极间自由表面附近局部自发极化变化的唯象理论。结果表明，去极化场效应减少了这种局部极化从其体积值的偏差，相比，在其他系统中的相变的表面效应。特别地，描述居里温度T C附近的局部极化的行为的临界指数与体指数相同，并且仅改变临界振幅。这种行为与其他系统（反铁电体，铁磁体和反铁磁体，有序合金等）中的相变形成对比。其中预测不同的指数。为了改善后，考虑到T C附近的统计波动的影响，这朗道型理论，最近的结果重整化群理论被用来估计对数校正因子，应该修改的临界行为的局部极化。最后，我们的结果的实验意义进行了简要的讨论，并讨论了表面效应对双极磁体的相变。
A phenomenological theory is developed to describe the change of the local spontaneous polarization in the vicinity of a free surface of a ferroelectric thin film which is kept between metallic electrodes. It is shown that depolarizing field effects reduce the deviation of this local polarization from its bulk value, as compared to surface effects on phase transitions in other systems. In particular, the critical exponents describing the behavior of the local polarization in the vicinity of the Curie temperature T C are the same as the bulk exponents and only critical amplitudes are changed. This behavior contrasts to phase transitions in other systems (antiferroelectrics, ferro-and antiferromagnets, ordering alloys etc.) where different exponents are predicted. In order to improve upon this Landau-type theory by taking into account the effects of statistical fluctuations near T C, recent results of renormalization-group theory are used to estimate logarithmic correction factors which should modify the critical behavior of the local polarization. Finally the experimental implications of our results are briefly discussed, and also a discussion of surface effects on the phase transition of dipolar magnets is given.