BiFeO3基多铁性薄膜异质结中尺寸相关逆磁电效应的相场模拟

项目名称： BiFeO3基多铁性薄膜异质结中尺寸相关逆磁电效应的相场模拟

项目编号： No.51472140

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无机非金属材料学科

项目作者： 陈龙庆

作者单位： 清华大学

项目金额： 83万元

中文摘要： 磁性/BiFeO3多铁性异质结具有丰富的物理内涵，其逆磁电效应可用于设计新型低功耗、多功能自旋电子器件。对于此类BiFeO3基多铁性异质结，其逆磁电效应的物理机制包含电荷效应、磁性交换作用、应变传递等多种。这些机制可在异质结界面处共存，它们相互之间的相互作用决定了逆磁电效应的大小。每一种机制的强弱不仅依赖于异质结的化学组分，也取决于异质结的面内尺寸和纵向厚度。 相场模型可模拟铁电、铁磁、多铁性材料的介观铁性畴结构在外加电场、磁场、应力场作用下的动态演化，并可据此评估材料的宏观物理特性。本项目提出构建BiFeO3基多铁性异质结逆磁电效应的相场模型，研究异质结多种不同跨界面耦合/作用机制的相互作用及它们对异质结尺寸的依赖，以加深对多铁性异质结中逆磁电效应物理机制的理解并为实验研究提供理论指导，推动多铁性磁电原型器件的设计与发展。

中文关键词： 铁酸铋；多铁性异质结构；器件设计；相场模型；尺寸效应

英文摘要： It has been established that there are abundant physic issues existing in magnet/BiFeO3 heterostructures, of which the converse magneto-electric effect can be used in the design of spintronic devices with low energy consumption and multi functionalities. In such BiFeO3 based multiferroic heterostructures, the mechanisms that induced the converse magneto-electric effect include charge modulation, magnetic exchange interaction, strain transfer, and so on. With the co-existence of these mechanisms at the interface of the heterostructures, the converse magneto-electric coupling strength is determined by the interactions among these mechanisms. The strength of each mechanism depends not only on the chemical composition, but also on the in-plane size and out-of-plane thickness of the heterostructures. Phase field model has been demonstrated to be a powerful tool for studying the meso-scale domain structures of the ferroelectrics, ferromagnets, and multiferroics, as well as their domain evolutions under externally applied electric field, magnetic field, and stress field, respectively. The macroscopic properties can also be evaluated according to the domain structures obtained from phase field simulations. In the present proposal, the phase field model of BiFeO3-based heterostructure will be constructed to study the couplings/interactions among the interfacial mechanisms on the converse magneto-electric effect as well as their dependences on the size of the heterostructures. The present proposal aims to make further understanding of the interfacial mechanisms that inducing the converse magneto-electric effect of the multiferroic heterostructures, so as to instruct the experimental studies and promote the design and development of multiferroics-based devices.

英文关键词： BiFeO3;Multiferroic Heterostructure;Device Design;Phase Field Model;Size Effect