直接在金属底电极上取向控制生长Bi系层状钙钛矿型多铁薄膜

项目名称： 直接在金属底电极上取向控制生长Bi系层状钙钛矿型多铁薄膜

项目编号： No.51472131

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 卢朝靖

作者单位： 青岛大学

项目金额： 83万元

中文摘要： 目前探寻在室温同时具有铁电和铁磁性且磁电耦合强的单相多铁材料是研究热点。在层状钙钛矿型Bi4Ti3O12铁电体中插入YFeO3等磁性基团是获得单相多铁物质的有效途径。实用要求在标准型Pt/Ti/SiO2/Si衬底上实现此类多铁薄膜沿近a/b轴均匀取向生长。我们的前期研究表明，薄膜晶化时用升温速率调整热应力和原位外加电场都可有效诱导晶粒取向成核成长。本申请拟用溶胶-凝胶工艺在Pt/Ti/SiO2/Si上制备沿近a/b轴均匀取向生长的Bi4Ti3O12-nAFeO3、Bi4Ti3O12-nAFe0.5Co0.5O3 (A = Y、La或Bi, n = 0.5、1.0、1.5或2.0) 多铁薄膜，摸索出一套在金属电极上控制Bi系层状钙钛矿型多铁薄膜取向生长的关键技术；建立制膜工艺-取向生长-显微结构关系，理解这种取向控制生长机制；筛选出在室温同时具有优良铁电、铁磁和磁电耦合特性的单相多铁薄膜。

中文关键词： 多铁薄膜；钙钛矿结构；取向生长；金属底电极

英文摘要： Multiferroic materials exhibiting ferroelectric and magnetic orderings simultaneously have been attracted much attention during the past decade. It is mainly attributed to the possibility of cross-controlling between magnetic field/electric field and polarization/magnetization in multiferroic materials, which provides a route in advanced memory devices. There has been an intense search for room-temperature magnetoelectric multiferroics within which the coupling of ferroelectric and ferromagnetic polarizations might be remarkably demonstrated. One of the most effective ways to obtain the excellent multiferroic properties in single-phase matters is to incorporate magnetic species of perovskite like YFeO3 into ferroelectric Bi4Ti3O12 matrix of layered perovskite. For their applications in high-density devices, it is necessary to grow uniformly a/b-axes-oriented (or near-a/b-axes-oriented) multiferroic thin films of Bi-layered perovskite on standard-type Pt/Ti/SiO2/Si substrates. Our previous research indicates that the nucleation and growth of oriented grains in the thin films can be effectively controlled by adjusting thermal stress during crystallization using different heating rates and by applying in-situ electrical field. In this work, we plan prepare Bi4Ti3O12-nAFeO3、Bi4Ti3O12-nAFe0.5Co0.5O3 (A = Y、La or Bi, n = 0.5、1.0、1.5 or 2.0) multiferroic thin films of uniform a/b-axes (or near-a/b-axes) orientation grown on Pt/Ti/SiO2/Si through sol-gel method. A key route for the controlled growth of uniformly-oriented multiferroic thin films with Bi-layered perovskite directly on metal electrodes will be find out. The mechanism of such orientation-controlled growth will be understood by establishing the growth process ? preferred orientation ? microstructure relation for these thin films. Single-phase multiferroic thin films exhibiting excellent magnetoelectric coupling properties at room temperature will be obtained. These oriented multiferroic thin films of Bi-layered perovskite are expected to match applications in high-density memory devices.

英文关键词： multiferroic thin films;perovskite structure;oriented growth;metal bottom electrodes