The single crystal of morphotropic-phase-boundary (MPB) Pb(Mg1/3Nb2/3)O3−PbTiO3 (PMN-PT) is widely utilized in ultrasonic medical imaging devices due to its excellent piezoelectric properties. In recent years, alternating-current (AC) poling has proven effective in enhancing these properties, though AC poling beyond optimal cycles can lead to deterioration. In this study, to gain deeper insights into the mechanisms driving the change of piezoelectricity, the response of ferroelectric domains in an MPB PMN–PT single crystal was examined using in situ AC field electrical biasing transmission electron microscopy. The ferroelectric domain structure was significantly altered by applying a single cycle of an AC electric field at 12 kV/cm peak-to-peak and 20 Hz. Subsequently, with increased AC field duration, both a reduction in domain wall density and the generation of vertical microdomain bands were observed. These phenomena could, respectively, enhance and degrade the piezoelectricity of the material.

中文翻译：

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铁电纳米域对形态相边界 Pb（Mg1/3Nb2/3）O3−PbTiO3 中交流电场的响应


形态相界 （MPB） Pb（Mg1/3Nb2/3）O3−PbTiO3 （PMN-PT） 的单晶由于其优异的压电性能而被广泛用于超声医学成像设备。近年来，交流电 （AC） 极化已被证明可有效增强这些特性，尽管超出最佳周期的交流极化会导致劣化。在这项研究中，为了更深入地了解驱动压电变化的机制，使用原位交流场电偏置透射电子显微镜检查了 MPB PMN-PT 单晶中铁电畴的响应。通过施加 12 kV/cm 峰峰值和 20 Hz 的交流电场的单个周期，铁电畴结构发生了显著变化。随后，随着交流场持续时间的增加，观察到畴壁密度降低和垂直微畴带的产生。这些现象可以分别增强和降低材料的压电性。