球形无规键无规场模型研究弛豫铁电体极化效应

Research on polarization effect for relaxor ferroelectrics by spherical random bond-random field model

基于球形无规键无规场模型和电场作用下弛豫铁电体微畴-宏畴机理,利用模糊畴界观点以及电场对极化的分数维效应,分析了电场对畴的作用机理.研究结果表明:电场对畴的诱导偶极子增量的极化效应导致了电滞回线的不饱和及相关的大的电致伸缩效应;而畴的偶极子增量耦合时结合能的变化对低电场的电滞回线略有影响,但基本不会改变高电场时的极化状态.初始微畴大小对电滞回线非常重要,细小的微畴会导致细长的电滞回线及电场与电致伸缩良好的线性关系.

Based on spherical random bond-random field model, micro-macro domain mechanism under electric field, and the fuzzy domain boundary with fractal dimension of electric field, the mechanism of polarization effect is analyzed. The results show that the effect of electric field on polarization effect of increment of domain dipoles leads to an unsaturated electric hysteresis loop and its associated big electrostrictive effect. But the variation of binding energy, when dipole couples to the increment of domain dipoles induced by electric field, has a little influence on electric hysteresis loop in a low electric field, and has almost no influence in a high electric field. The initial size of the micro domain is very important for electric hysteresis loop： small micro domain can lead to a long electric hysteresis loop and better linear relationship between electric field and electrostriction.