Electric-field-driven phase transformation phenomena in multiferroic BiFeO3 are directly linked to the functionalities of electronic devices based on multiferroic materials. Understanding how the transformation evolves at the nanoscale under the influence of an electric field will provide fascinating insights into key parameters that utilize the transformation features. Here, we report both the electric-field-driven transient and permanent phase transformations in highly strained BiFeO3 thin films and their transformation dynamics at the nanoscale. We found that two distinct transient and permanent phase transformations were triggered below and above a coercive voltage of the polymorphic phase, indicating that ferroelectric polarization switching could promote permanent phase transformations. We also found that the transient transformations evolve via complex phase boundary motions between the coexisting phases, whereas permanent transformations occurred via nucleation of the other phases.

中文翻译：

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高应变外延 BiFeO3 薄膜中的电驱动瞬态和永久相变

多铁性 BiFeO3 中的电场驱动相变现象与基于多铁性材料的电子设备的功能直接相关。了解在电场影响下的纳米尺度上的转变如何演变，将为利用转变特征的关键参数提供迷人的见解。在这里，我们报告了高应变 BiFeO3 薄膜中电场驱动的瞬态和永久相变及其在纳米尺度上的转变动力学。我们发现在多晶相的矫顽电压之下和之上触发了两种不同的瞬态和永久相变，表明铁电极化切换可以促进永久相变。