弛豫铁电单晶宽频(10mHz-20GHz)介电性能研究

项目名称： 弛豫铁电单晶宽频(10mHz-20GHz)介电性能研究

项目编号： No.51202183

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 无机非金属材料学科

项目作者： 靳立

作者单位： 西安交通大学

项目金额： 25万元

中文摘要： 同传统的铁电锆钛酸铅陶瓷材料相比，弛豫铁电单晶材料因其准同型相界成分附近的高压电与介电性能而被广泛的关注。目前，弛豫铁电单晶材料的常规压电、介电、弹性性能已被广泛深入的研究。而对于其准同型相界成分附近高性能的起源现在依然存在争议。代表性的观点多从本征晶格与非本征畴壁移动的角度来解释这一现象。实验上将二者定量的加以区分依然存在很大的难度。本项目将从弛豫铁电单晶的宽频(10mHz-20GHz)介电性能与相结构/畴结构的关系入手，利用微波介电弛豫现象将本征晶格与非本征畴壁移动对于介电性能的贡献加以区分。并以此为突破口，探讨弛豫铁电单晶高介电性能的起源问题。同时研究不同畴壁移动机理在此频率范围内的响应特性，并与最近提出的普适畴壁动力学理论模型相验证。在应用方面，本项目将归纳弛豫铁电单晶宽频介电性能与外场的关系，探索优化介电性能的技术路线，为开发新的微波介电器件提供材料研究的基础。

中文关键词： 弛豫铁电单晶；宽频介电性能；铁电畴；非本征性能；

英文摘要： Compared with traditional ferroelectric lead zirconate titanate ceramics, relaxor ferroelectric single crystals with the composition near the morphotropic phase boundary (MPB) region have attracted much attention due to their superior piezoelectric and dielectric properties. Up to date, the routine piezoelectric, dielectric and elastic properties of relaxor ferroelectric single crystals have been widely studied. However, the origin of high properties of them near the MPB region is still under debate. Many representative opinions based on intrinsic crystal lattice and extrinsic domain wall motion have been proposed to understand this phenomenon. It is very difficult to separate one mechanism from the other by means of experiments. In this proposal, we will study the relationship between the broadband (10mHz-20GHz) dielectric properties and the corresponding phase/domain structures of the relaxor ferroelectric single crystals. Making use of the microwave dielectric relaxation, we could separate the domain wall motion from the crystal lattice contribution to the dielectric properties. Based on these experiments results, we could identify the origin of the high properties of the relaxor ferroelectric single crystals with the composition near MPB. We will also investigate different response characteristics govern by

英文关键词： relaxor ferroelectric single crystal；broadband dielectric properties；ferroelectric domain；extrinsic properties；