原位应变调控钙钛矿铁电薄膜居里温度及性能研究

项目名称： 原位应变调控钙钛矿铁电薄膜居里温度及性能研究

项目编号： No.11204179

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 王飞飞

作者单位： 上海师范大学

项目金额： 29万元

中文摘要： 以航天航空、能源、石油化工、汽车为代表的众多领域，要求铁电材料能够在较宽温度范围内工作，开发兼有高居里温度、高电性能的铁电体系已成为当前国际上研究热点之一。针对准同型相界附近具有优良压电响应的一类钙(MPB)钛矿固溶体居里温度、相变温度较低的问题（如铅基体系的(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3和无铅的(1-x)Bi0.5Na0.5TiO3-xBaTiO3），本项目通过制备自组装纳米复合材料的方法，利用晶格常数及弹性模量不同而产生的垂直原位应变，实现在三维方向调控这类铁电薄膜材料，重点研究MPB组分钙钛矿铁电薄膜的相结构与微观形貌、电畴结构、居里温度、铁电相变温度及相关电性能受复合组元的晶格常数、弹性系数、含量、衬底取向、薄膜厚度等参数的影响规律，并探索相关的生长与调控机理，从而提高这类钙钛矿铁电薄膜的温度使用范围。

中文关键词： 原位应变；准同型相界；钙钛矿；薄膜；相变温度

英文摘要： In most applications represented by the automotive and aerospace industries, the ferroelectric materials are required to work over a broad temperature range. Design and fabrication of high performance ferroelectric materials with high Curie temperature is a hot research topic at present. The perovskite solid solutions such as (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 and lead-free (1-x)Bi0.5Na0.5TiO3-xBaTiO3 with the composition around the morphotropic phase boundary has attracted much attention recently due to the outstanding electrical performances. However, their relatively lower Curie or depoling temperature greatly restricts their applications in sensors, actuators, and ultrasonic transducers. The present study aims to substantially improve this through introducing a self-assembled nanocomposite structure to create vertical in situ strain. The emphasis will be focused on the relations between the phase structure, domain state, Curie temperature, ferroelectric phase transition temperature, electrical properties and the component, elastic constant, substrate, film thickness etc.so as to reveal the growth and control mechanisms and improve the temperature usage range.

英文关键词： In situ strain；MPB；Perovskite；Thin film；Phase transition temperature