自旋失措型多铁性氧化物ABO2中的磁电耦合效应研究

项目名称： 自旋失措型多铁性氧化物ABO2中的磁电耦合效应研究

项目编号： No.11304322

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 李仁文

作者单位： 中国科学院合肥物质科学研究院

项目金额： 30万元

中文摘要： 多铁性材料由于同时拥有磁性和铁电性，存在磁电耦合并可以相互调控，是一种具有广泛应用前景的新型多功能材料。当前面临的挑战是弄清磁性和铁电性相互耦合与调控的微观机制，以及如何实现两者之间的强耦合。在螺旋状自旋结构的多铁性材料中，磁性和铁电性是本征关联的，因而极有可能获得强的磁电耦合和可靠的磁性/铁电性相互调控。自旋失措的多铁性材料中存在复杂的自旋、电荷、轨道和晶格自由度之间的竞争和耦合。目前关于自旋失措的螺旋自旋排列导致的铁电性和磁电耦合的起因还不清楚。本项目拟制备ABO2型自旋失措多铁性氧化物，通过晶格调制、价态调制和磁性离子掺杂等手段来调控其中的磁性和铁电性，给出其中自旋、电荷、轨道和晶格间相互作用规律，并结合外部磁场、电场、压力等手段调节体系自旋有序和铁电有序及其耦合关系，获得自旋失措螺旋磁结构的多铁性材料中铁电性和磁电耦合的调控规律，为寻找和设计强磁电耦合的多铁性材料提供实验基础。

中文关键词： 自旋失措；自旋有序；多铁性；磁电耦合；电荷有序

英文摘要： Multiferroic materials, which are simultaneously ferromagnetic and ferroelectric, have drawn increasing interests due to their potential for applications as multifunctional devices. In multiferroics, the coupling interactions and mutual controls among the the different parameters could produce new effects, such as magnetoelectric (ME) coupling effect. Now, it is important to uncover the mechanics of the ME coupling and achieve the strong ME coupling. In the multiferroics induced by spiral spin orders, the magnetization and polarization are intrinsically connected with each other. So it is highly possible to achieve high ME coupling and reliable control in this kind of multiferroic materials. There exsit complex interactions among the spin, charge, orbit and lattice in the proper-screw type multiferroics with spin frustrations. Now the origin and intrinsic mechanism of the ME coupling and the ferroelectricity induced by proper-screw type spin order are still controversial. In this project, we choose the ABO2-type oxides with spin frustration as the study objects. We plan to modulate the magnetic and ferroelectric order in the system through the lattice modulation, valence modulation and doping with magnetic ions, combined with the high magnetic field, electric field and material preparing under the high magnetic

英文关键词： spin frustration；spin ordering；multiferroicity；magnetoelectric coupling；charge ordering