应力场下铁酸铋材料的相结构、畴结构和原子极化特性的亚埃尺度研究

This project aimed at the phase structure, domain structure and atomic polarization characteristics as well as their evolution behaviors in stressed BiFeO3 (BFO). By using aberration corrected transmission electron microscope (AC-TEM) method and in situ force-electronical properties measurement techniques (STM-TEM), we take advantages of the high special resolution of the AC-TEM and the in situ nano-manipulation and force-electrical properties measurement ability of the STM-TEM, and it is suggested to study dynamics of phase structure, domain structure, and atomic polarization in BFO material under stress fields with different directions and intensity, deep to sub-angstrom atomic-resolution dimension. In combination with first-principle theoretical simulations and calculations, several foundamental physical aspects on the effect and controlling of stress on phase structure, domain structure and atomic polarization of BFO material will be studied and revealed. The relationship between stress and material structure/properties will be clarified in part. This project focuses on the key foundamental science problem on a typical material with good properties. It makes full use of the researchers’ research conditions and foundation. The realization of this project will show significance in providing valuable information and pushes strongly the progress of the relating fields.

本项目针对应力场下铁酸铋材料的相结构，畴结构和原子极化特性及其演化行为的问题，提出使用原子分辨球差校正透射电子显微学的方法，并结合原位力、电性能测试技术，充分利用球差校正透射电子显微镜的高空间分辨率以及原位力、电测试系统的高精度原位纳米操纵和原位力、电性能测试功能，在亚埃原子尺度对铁酸铋材料在不同方向和大小的应力场下的相转变规律，原子极化特性和畴结构动力学规律进行观测。结合第一性原理理论模拟和计算，深入探索应力对材料结构、性能的影响和调控规律及其深层次物理机制，获得应力作用下铁酸铋材料的相结构、畴结构和原子极化位移特征及其演化、运动的若干机制和规律。本项目针对具有优良性能的典型材料体系中的关键基础科学问题，结合本实验室的研究条件和已有研究基础，发挥自身的研究强项对其进行细致的研究。其实施有望获取若干对相关领域具有显著参考价值的信息，对相关领域的发展起到有力的推动。

铁酸铋（BFO）材料中的多种相结构及其转变规律是决定其性质的主要因素。但是，长期以来，研究人员对其中具体的微观机理并不十分了解。针对这一课题，本课题组从材料制备到性能表征以及原型器件的制备几个方面进行了若干有益的探索，结合使用多种方法和手段进行了较仔细的研究。掌握了BFO高质量单晶的制备方法，了解了其相结构的分布规律，探究了其原子结构特性，以及BFO材料中的自旋波特性。项目的实施对进一步深入理解和调控BFO材料的多铁行为和耦合特性提供了有用的信息，对相关领域的研究具有一定的参考价值。