Raghuraman Shivaranjan, Vasudevan Rama K, Yang Jan-Chi, Kelley Kyle P, Domingo Neus, Jesse Stephen
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, TN 37830, USA.
Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan.
Small Methods. 2025 Jul;9(7):e2401565. doi: 10.1002/smtd.202401565. Epub 2025 Jan 10.
Understanding ferroelectric domain wall dynamics at the nanoscale across a broad range of timescales requires measuring domain wall position under different applied electric fields. The success of piezoresponse force microscopy (PFM) as a tool to apply local electric fields at different positions and imaging their changing position, together with the information obtained from associated switching spectroscopies has fueled numerous studies of the dynamics of ferroelectric domains to determine the impact of intrinsic parameters such as crystalline order, defects and pinning centers, as well as boundary conditions such as environment. However, the investigation of sub-coercive reversible domain wall vibrational modes requires the development of new tools that enable visualizing domain wall motion under varying applied fields with high temporal and spatial resolution while also accounting for spurious electrostatic effects. Here, scanning oscillator piezoresponse force microscopy extends the investigation of domain wall dynamics to new regimes, providing direct visualization of domain wall position as a function of an external electric field that varies in time and location. This enables studying the energetics of field-driven ferroelectric domain wall motion, which is shown to obey a thermally activated flow regime in the millisecond timescale.
要在广泛的时间尺度上理解纳米尺度的铁电畴壁动力学，需要测量不同外加电场下的畴壁位置。压电力显微镜（PFM）作为一种在不同位置施加局部电场并对其变化位置进行成像的工具，以及从相关开关光谱学获得的信息，推动了对铁电畴动力学的大量研究，以确定诸如晶体有序度、缺陷和钉扎中心等内在参数以及诸如环境等边界条件的影响。然而，对亚 coercive 可逆畴壁振动模式的研究需要开发新的工具，这些工具能够在高时间和空间分辨率下可视化不同外加电场下的畴壁运动，同时还要考虑虚假的静电效应。在这里，扫描振荡器压电力显微镜将畴壁动力学的研究扩展到新的领域，提供了作为时间和位置变化的外部电场函数的畴壁位置的直接可视化。这使得能够研究场驱动的铁电畴壁运动的能量学，结果表明在毫秒时间尺度上它遵循热激活流动机制。
