铋基钙钛矿弛豫铁电陶瓷电致大应变、温度依赖性及其相关机理研究

Bismuth based perovskite-structured solid solution materials can exhibit electric field induced giant strains through appropriate compositional modification or temperature modulation, being expected to become one type of novel ceramic materials for the application of displacement actuators. Deep and systematic fundamental study and comparative study will be carried out in current project, focusing on the feature and the physical mechanism of the generation and its temperature sensitivity of the electric field induced large strain in one type of ceramics with ABO3-typed perovskite structures, and the limitation of experimental and theoretical aspects existing in current literature researches. On the basis of the applicants' preliminary work, the multi-layered multi-scaled analysis methods were employed to more deeply explore the common issues in the interrelation between the composition, the structural evolution (fine phase structure, domain structure and local structure) and macroscopic electrical properties (dielectric relaxation behavior, ferroelectric and strain properties). The aim is to disclose the inherent links of the composition and temperature modulation, the evolution of dielectric relaxation behavior and the electric field induced strain behavior. Based on this, the similarities and differences, and the structural origin of the composition or temperature sensitivity of bismuth based perovskite structured ceramics were further explored. The law of the compositional design and the technological scheme for improving the temperature and composition dependences of large strains were searched. The establishment and execution of this project will be expected to provide a solid theoretical and experimental basis for further designing and preparing bismuth based perovskite structured ceramics for actuators.

铋基钙钛矿及其固溶体经适当的组成改性或温度调制能够呈现出巨大的电场诱发应变，有望成为一类新型的位移驱动器用陶瓷材料。本项目针对ABO3型铋基钙钛矿这一类陶瓷材料的电致应变特性、大应变的产生及其温度敏感性的物理机制，以及当前文献研究中存在的一些实验及理论上的不足之处，开展深入系统的基础研究和对比研究。在申请人前期工作基础上，借助多层次多尺度的分析手段对这一类材料体系在组成、结构演变（精细相结构、电畴结构及局域结构）和宏观电学性能（介电弛豫行为，铁电和应变性能）相互关系上的共性问题进行更加深入的探讨，揭示组成和温度调制、介电弛豫行为演变和电致应变行为的内在联系。并在此基础上，进一步探索其电致应变温度/组成敏感性的异同及其结构起源，探寻改善大应变的温度/组成依赖性的组成设计规律和技术方案。该项目的立项实施有望为进一步设计和制备驱动器用铋基钙钛矿陶瓷材料提供坚实的理论和实验基础。

本基金项目以ABO3型铋基钙钛矿这一类材料体系及其固溶体为研究对象，通过掺杂改性以及取代形成固溶体，研究其组成、温度及其外电场对其相结构、局域结构、电畴结构，及其宏观电学性能的影响，成功地阐明铋基钙钛矿固溶体材料通过组成调控介电行为的基本规律，揭示介电弛豫行为的演变和电场诱发大应变的相关性，揭示正常-弥散-弛豫相变在原子尺度上的结构变化，及其和宏观对称性变化的内在联系，并借助同步辐射XRD等先进技术手段，建立铋基钙钛矿这一类材料的组成-精细相结构/局域结构-宏观电学性能的内在联系，阐明其电场诱发大应变及其温度敏感性的本征结构机理。