多场耦合下铁电薄膜非线性行为的畴变模型

铁电薄膜在外加力场, 电场和温度场的作用下表现出明显的非线性, 为了更好的描述这种现象, 本文提出了一个热-电-力耦合场铁电薄膜下的畴变模型。该模型基于细观力学模型, 认为电畴自由能的改变提供电畴翻转的动力, 且180°电畴翻转由两步90°翻转构成。在本构关系中加入了铁电薄膜制备过程中产生的残余应变项, 以区别于块体铁电材料, 通过该模型计算出了铁电薄膜在不同外场下的响应, 结果与实验和其他模型的结果较为符合。

Modeling and Simulation of Non-Linear Behavior of Ferroelectric Films in Coupled Thermo-Electro-Force Fields

The interaction of the ferroelectric coatings and stress/strain, electric and temperature fields was mathematically formulated with the novel domain-switching model in which the domain switching is activated by the free energy between domain states and based on the expanded micro-mechanical model, theoretically analyzed and numerically simulated to understand its non-linear behavior.Moreover, to differentiate the film from the bulk ferroelectric materials in the coupled thermo-electro-force fields, the remnant strain was considered.The simulated results show that the temperature, electric and strain/stress fields all have a major impact.To be specific, as the temperature increases, the domain becomes less stable and switches easier because of the increasing free energy; an increase of the strain decreases the free energy and makes it more difficult to switch the domains.The simulated results agreed fairly well with the experimental and simulated results reported in literature.