Analysis of ferroelectric switching in finite media as a Landau-type phase transition
Analysis of ferroelectric switching in finite media as a Landau-type phase transition
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DOI：
10.1088/0953-8984/10/2/026
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发表时间：
1998-01
期刊：
影响因子：
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通讯作者：
D. Ricinschi;C. Harnagea;Constantin Papusoi;L. Mitoseriu;V. Ţura;M. Okuyama
中科院分区：
文献类型：
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作者：
D. Ricinschi;C. Harnagea;Constantin Papusoi;L. Mitoseriu;V. Ţura;M. Okuyama
在朗道相变模型的框架下，对铁电体中的极化反转进行了详细的分析。均匀开关的一些重要特性已经被强调，并在以后用于研究更一般的情况下，非均匀开关。开关电流的两个极端对应于介电磁滞回线的导通点。极化铁电体样品的磁滞回线预计将包括负磁化率区域，高频施加电场。开关电流的最小值被用来记录开关响应的实验方法消除。定义了等效的朗道系数和电场，以综合尺寸效应和非均匀性对全局序参量开关的贡献。我们相关的开关（矫顽场）和铁电-顺电相变（居里温度）的关键参数的尺寸效应。小尺寸铁电体中的极化反转可以看作是一种扩散相变，而大尺寸铁电体中的极化反转则更接近于正常的相变。反转速度和最大电流的尺寸依赖性来自于等效朗道系数和电场诱导反转的尺寸依赖性。
A detailed analysis of polarization reversal in ferroelectrics has been performed, in the framework of the Landau model for phase transitions. Some important characteristics of homogeneous switching have been emphasized and later used in studying the more general case of inhomogeneous switching. The two extremes of switching current correspond to the inflexion points of the dielectric hysteresis loop. Hysteresis loops of poled ferroelectric samples are expected to include negative-susceptibility regions, for high-frequency applied electric fields. The switching current minimum is eliminated by the experimental method used for recording the switching responses. Equivalent Landau coefficients and electric fields have been defined, in order to integrate the size effects and inhomogeneity contribution to switching of the global order parameter. We correlated the size effects on the critical parameters of the switching (the coercive field) and the ferroelectric-to-paraelectric phase transition (the Curie temperature). Polarization reversal in small-size ferroelectrics can be regarded as a diffuse phase transition, whereas its character is closer to normal for large-size samples. The size dependencies of the reversal speed and maximum current result from the size dependencies of the equivalent Landau coefficients and electric field inducing reversal.