三元体系弛豫铁电单晶PHN-PMN-PT具有超高压电响应的研究

项目名称： 三元体系弛豫铁电单晶PHN-PMN-PT具有超高压电响应的研究

项目编号： No.11504373

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 李修芝

作者单位： 中国科学院福建物质结构研究所

项目金额： 21万元

中文摘要： 以铌镁酸铅-钛酸铅（PMN-PT）为代表的复合钙钛矿型弛豫铁电单晶材料的出现开启了铁电材料研究及应用的新纪元，成为目前备受关注的一类重要功能材料。但在实际应用中PMN-PT存在着居里温度低、性能不稳定的缺点，所以探索具有高居里温度高压电性能的新型弛豫铁电单晶以替代PMN-PT单晶成为发展新一代高性能压电器件亟待解决的关键问题。前期对PHN-PMN-PT三元系弛豫铁电单晶已经进行初步研究，生长出了三方相和四方相的单晶，晶体具有超高的压电性能和优异的机电耦合性能。本项目拟在前期工作的基础上首先确定单晶的准同型相界（MPB）组成；研究PHN-PMN-PT三元铁电单晶在MPB区域附近的顺电-铁电相变规律、三方-四方相变规律；研究MPB附近的相结构、畴结构的特点；建立PHN-PMN-PT晶体具有超高压电效应的物理机制和理论模型，用于指导探索新的高性能弛豫铁电单晶材料。

中文关键词： 压电效应；弛豫铁电单晶；压电性

英文摘要： The emergence of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT), typical relaxor ferroelectric single crystals with multiple perovskite structures, turns on a new era of the research and application of ferroelectric materials. Much attention are paid on these materials, which become a kind of important function materials. Single crystals of PMN-PT with compositions close to or within the morphotropic phase boundary (MPB) region have been the topic of intensive studies in the past years because of their high piezoelectric coefficients, large longitudinal electromechanical coupling factors, high dielectric constants and low dielectric losses, which point to a wide range of applications in advanced technologies. However, there are some drawbacks in this system. The low values of the Curie temperature (TC) and the rhombohedral-tetragonal phase transition temperature (TR-T) make the materials depoled easily, greatly limit their applications in the high temperature range. Therefore, it is important to develop new relaxor ferroelectric single crystals with both high Tc and high piezoelectric properties to replace PMN-PT. Compared with PMN-PT single crystals, the ternary single crystals have attracted much attention due to their promising piezoelectric properties, high TC and TRT. The ternary crystal of Pb(Ho1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PHN-PMN-PT) were grown by TSSG method in previous work. The structural and the di-/piezo-/ferro-electric properties of the grown crystal were characterized. The results show that it has super higher piezoelectric coefficient and longitudinal electromechanical coupling coefficient. This item aims at determine the composition of the the morphotropic phase boundary (MPB) region, investigate the electrical properties and the phases and domains near the MPB and, clarify the mechanism of the super high piezoelectric response. If the proposal will be supported, 5-8 papers will be published on the international journal and 2-4 invention patents will be submitted.

英文关键词： piezoelectric effect;relaxor ferroelectric single crystal;piezoelectric property