压电材料的相场模拟-中国材料进展

文章信息/Info

Author(s):: Ke Xiaoqin; Xiaobing Ren; Wang Yunzhi; Frontier Institute of Science and Technology, Xi’an Jiaotong University

摘要:: 压电材料是一种能够在机械能和电能之间互相转换的材料，在制动器，传感器等器件上应用广泛。高性能压电材料通常都出现在铁电固溶体相图的准同型相界附近，因此研究准同型相界附近出现高压电性能的机理对于开发新的压电材料至关重要。本文主要综述了利用相场模拟的手段研究准同型相界附近压电材料的微观结构以及高压电性能机理的进展。在微观结构方面，我们通过相场模拟得到了准同型相界附近与实验类似的阶梯式纳米畴结构，并且发现这些纳米畴是最近实验发现的单斜相，该单斜相可以由长程静电能和弹性能所稳定。在压电性能方面，我们通过相场模拟发现，准同型相界附近的高压电性能主要来自于极化旋转而非畴壁移动的贡献。

Abstract:: Piezoelectric materials are materials that can convert mechanical energy to electric energy and vice versa and they are widely used in transducers and actuators. The best piezoelectricity normally appear at the so called morphotropic phase boundary(MPB) in the phase diagram of ferroelectric solid solutions. Thus understanding the mechanism of good piezoelectric properties at the MPB can guide designing new piezoelectric materials. This review summarized the progress in simulating the microstructure of piezoelectric materials at the MPB as well as the mechanism of good piezoelectric property there through phase field simulations. On the microstructure, we obtained hierarchical nanodomain structure as observed by experiments by phase field simualation and our work shows that these nanodomains are the newly discovered monoclinic phase and this new phase is stabilized by long range electrostatic energy and elastic energy. On the piezoelectric property, we showed by phase field simulation that the good piezoelectric property appearing at the MPB mainly comes from the contributions from polarization rotation rather than domain wall movement.