Domain-wall dynamics under strong, super-coercive electric fields in polycrystalline bismuth ferrite (BiFeO3) are not well established due to the experimental difficulties in processing high phase purity perovskite with low electrical conductivity. Overcoming these difficulties, here we present x-ray diffraction measurements carried out in situ during electrical poling with a trapezoidal electric-field to investigate the domain wall dynamics and lattice strain in this material. It is observed that during field ramping, microscopic strains, i.e., non-180° domain texture and lattice strain, increase simultaneously. During DC field dwell, however, a lattice strain decrease occurs over time, accompanied by an increase in the non-180° domain texture. This inverse time-dependent trend of microscopic strain mechanisms is speculated to be due to mobile charged defects residing in domain wall regions. The configuration of these charged point defects may also play a role in the observed post-poling relaxations of n...

中文翻译：

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铁氧体中极化诱导的反时限微应变机制和极化后弛豫

由于在处理具有低电导率的高相纯度钙钛矿方面存在实验困难，因此在多晶铁氧体铋 (BiFeO3) 中强、超矫顽力电场下的畴壁动力学尚未得到很好的建立。克服这些困难，我们在此介绍了在梯形电场电极化期间原位进行的 X 射线衍射测量，以研究该材料的畴壁动力学和晶格应变。可以观察到，在场斜坡期间，微观应变，即非 180° 域纹理和晶格应变，同时增加。然而，在 DC 场驻留期间，晶格应变会随着时间的推移而减少，同时伴随着非 180° 域纹理的增加。据推测，微观应变机制的这种反时间依赖趋势是由于畴壁区域中的移动带电缺陷造成的。这些带电点缺陷的配置也可能在观察到的 n...