用于压电器件的锆钛酸铋钠基材料的局部结构研究

针对当前铁电压电领域亟待解决的新一代环保无铅压电材料开发问题，结合项目申请人在高性能含铅压电材料局部结构与压电响应理论模型方面的前期工作基础，选择具有复杂局部结构的钛酸铋钠基材料作为基础，对其进行锆元素的化学掺杂，形成Na1/2Bi1/2(Ti,Zr)O3以及Na1/2Bi1/2(Ti,Zr)O3-BaTiO3固溶体，系统研究固溶体不同成分下的晶体结构，重点通过中子衍射和同步辐射全散射实验研究不同相干长度下的平均结构和局部结构，同时通过原位实验手段，研究电场作用下晶格参数变化和畴壁移动对整体材料形变的贡献，以此为基础寻找极化矢量旋转和畴壁运动活性较大的准同型相界成分，进而从本征贡献和外源贡献两个角度提高材料的压电性能，设计制造出新一代可与含铅材料性能相媲美的无铅压电材料和器件。

Aiming towards the current challenge of the development of the environmental-friendly lead-free piezoelectric material, in combination with the applicant's previous experience on the lead-based materials' local structure and the giant piezoelectric response theoretical model, we propose to choose the (Na,Bi)TiO3 based material which has complex local structure for chemical modification into the Na1/2Bi1/2(Ti,Zr)O3 and Na1/2Bi1/2(Ti,Zr)O3-BaTiO3 solid solutions, and to systematically study the crystal structures under different compositions of the solid solution. We will use neutron or synchrotron total scattering methods to study the average structure and the local structure with different coherent lengths, and use in-situ experiments to study the contributions from the lattice change and the domain motions to the deformation of the bulk material under electric field. A morphotropic phase boundary composition will be searched on the basis of the mobility of polarization rotation and domain wall motion, and therefore to enhance the piezoelectric properties from the aspects of intrinsic and extrinsic contributions.Finally we aim to design and manufacture the next generation high response, environmental friendly, lead-free piezoelectric materials and devices.