弛豫多铁性材料研究进展

Progress of Relaxor Multiferroic Materials

多铁性材料同时具有多种铁性(铁电性、铁磁性或铁弹性)的有序,可实现电磁信号的相互控制,成为近年来研究热点。在具有成分无序的复杂体系中,长程铁性有序有可能被打破,材料将表现出弛豫特性。我们将至少存在一种铁性弛豫特性的多铁性材料称之为弛豫多铁性材料。这类多铁性材料的极化强度(或磁化强度)在外加电场(或外加磁场)作用下响应更加灵敏,其磁电耦合机制与长程有序的多铁性材料不同。本文结合国内外最新研究成果,首先介绍了和弛豫铁性有序相关的物理概念,重点阐述了多铁性材料在铁电和铁磁双弛豫态下的磁电耦合机制;然后,详细介绍了钙钛矿结构(包括Pb B_1B_2O_3基和Bi Fe O_3基材料)和非钙钛矿结构(包括层状Bi结构和非正常铁电体)弛豫多铁性材料的研究进展;最后,对该领域亟待解决的问题进行了展望。

The multiferroic material, which shows the coexistences of multi ferroic orders（ferroelectricity, ferromagnetism or ferroelasticity）, can realize the mutual control of the electric and magnetic signals, and becomes one of the hottest research topics. The long-range ferroelectric or ferromagnetic order may be broken in compositionally disordered systems. In this situation, it is posssible that materials display relaxor behavior. Multiferroic materials possessiong at least one ferroic relaxor character can be named as relaxor multiferroics. The polarization（or magnetization） is very sensitive to the applied electric field（or magnetic field）. Besides, the magnetoelectric coupling effect of relaxor multiferroics is different from that of multiferroics with long ferroic orders. In this paper, the most recent and important theoretical and experimental advances in this new research field are reviewed. Firstly, basic physical concepts of the relaxor ferroic orders and the different mechanism of the magnetoelectric coupling effect on materials are introduced with the coexistence of relaxor ferroelectric ordering and relaxor magnetic ordering. Then, the recent researches on two sorts of the relaxor multiferroics, including perovskite（Pb B1 B2 O3 based and Bi Fe O3 based） and non-perovskite（Bi-layered based and improperly ferroelectric based） structural materials, are reviewed. Finally, the further development of relaxor multiferroics is prospected.