在已知的多铁性材料中,由磁性诱导铁电性的第二类多铁性材料具有较强的磁电耦合,但这类材料的临界温度往往很低,且自发极化强度很小。而正交结构的稀土铁氧体(RFeO3)具有很高的反铁磁相变温度(620~760 K),最近的研究表明其具有较强的室温铁电性,因而有望成为新的室温多铁性材料。本文综述RFeO3多铁性研究的最新进展,并讨论其可能的多铁性机制。

Among the multiferroic materials, type-II multiferroic materials where the ferroectricity is induced by the magnetism, indicate relatively strong magnetoelectric coupling. However, the critical tem-perature is generally very low in such kind of materials, and the spontaneous polarization is very small. On the other hand, the rear earth orthoferrites (RFeO3) indicate very high TN (620～760 K), and the recent investigations have indicated the relative strong ferroelectricity at room tem-perature, and they are expected as the promising new system of room temperature multiferroic materials. In the present review, the updated progresses on multiferroic RFeO3 are reported together with the discussion on the possible multiferroic mechanisms.

磁致多铁材料是多铁性材料大家族中的后起之秀,其特色在于其铁电性起源于特定的磁序,因此其铁电性与磁性紧密关联,具有本征的强磁电耦合效应。目前对磁致多铁性的研究以基础物理为主。随着对磁致多铁现象背后物理机制认识的不断深入,不断有新的磁致多铁材料被设计、预言和发现,其性能也在不断地提高。文章简要介绍了磁致多铁材料所涉及的基本物理机制,并根据这些已知的规律,回顾了近年来寻找和设计新的磁致多铁材料的经验。

Magnetic multiferroics belong to an important branch of the big multiferroics family. Because the ferroelectric polarizations are directly induced by particular magnetic orders, magnetic multiferroics exhibit strong intrinsic magnetoelectric coupling. Current research on mag-netic multiferroics is mostly focused on their fundamental physics. Benefitting from the progress of research on physical mechanisms, more and more new magnetic multiferroic materials have been designed, predicted, and discovered, with continual improvement in their magnetoelectric per-formance. We review briefly the physical mechanisms involved in magnetic multiferroics, as well as the efforts in recent years to search for and design new magnetic multiferroics.

铁酸铋是唯一一种在室温下存在的单相多铁材料,因其具有较高的铁电居里温度、较大的剩余极化强度、较小的禁带宽度和多铁特性,受到国内外的广泛关注。溶胶-凝胶法是制备铁酸铋薄膜的一种常见方法。综述了近年来溶胶-凝胶法制备铁酸铋薄膜的研究进展,详细阐述了制备工艺参数(前驱液、退火温度、退火气氛、底电极)与掺杂对铁酸铋薄膜电性能的影响;分析了不同制备工艺导致薄膜电性能出现差异的原因;归纳、总结出了目前溶胶-凝胶法制备铁酸铋薄膜的较佳工艺条件;最后,指出了亟待解决的问题。

Bismuth ferrite is the only single-phase multiferroic material at room temperature. BFO materials received extensive attention because of its high ferroelectric Curie temperature, large remnant polarization, narrow band gap and multiferroic property. sol-gel method is a common method for preparation of bismuth ferrite thin film. The research progress in the effects of process pa-rameters ( such as precursor solution, annealing temperature, annealing atmosphere, bottom electrode) and dopants on the electri-cal properties of bismuth ferrite thin films was reviewed. The reasons that different preparation processes led to distinct electrical properties of BFO thin films were analyzed. The superior preparation conditions of BFO thin films via sol-gel were summarized. Fi-nally, some problems to be solved were put forward.

1-3压电复合材料的压电、介电及铁电性能要远远优于0-3压电复合材料.在制备传统的0-3复合材料过程中引入电泳技术,使得压电颗粒在聚合物基体中取向排列,制备得到伪1-3复合材料.实验结果表明:在制备PZT/环氧树脂0-3复合压电材料固化过程中,采用500 V/mm,4 kHz的电场对其进行电泳辅助取向,可使得颗粒呈现珍珠串状排列,得到伪1-3复合材料;其压电、介电、铁电性能均比原来的0-3复合材料有显著的提高.电泳辅助制备技术用于制备伪1-3复合压电材料具有操作简单、成本低廉、压电、介电、铁电性能显著提高等优点,在智能传感领域具有很好的实际应用前景.

The 1-3 ceramic/polymer piezoelectric composites have greater dielectric, piezoelectric and ferroelectric properties than 0-3 composites. In this paper, electrophoresis is introduced into the fabrication procedure of traditional 0-3 ce-ramic/polymer piezoelectric composite to move and pearl-serially align the piezoelectric particles in the polymer matrix, which is called pseudo 1-3 composite. In this work, the PZT/ epoxy pseudo 1-3 piezoelectric is fabricated via using a 500 V/mm, 4 kHz AC electric field to form the electrophoresis phenomenon during the curing procedure. Compared with the traditional 0-3 piezoelectric composites, the pseudo 1-3 piezoelectric composites behave as the significantly-enhanced dielectric, piezoelectric and ferroelectric performances on basis of our theoretical analysis and experimental measurement result. Electrophoresis-assisted fabricating pseudo 1-3 piezoelectric composite possesses the advantages of simple opera-tion, low cost and significant performanc

铁磁、铁电和多铁性材料，被称为信息存储终极材料，近来已成为国际上一个新的研究领域。多功能材料BiFeO3是著名的铁电、压电和磁电材料，在远高于室温的范围内具有良好的铁电性，其铁电极化是同类材料中最大的，因而受到科研人员的强烈关注，越来越多的新奇物理性质被发现。本文探讨 A位稀土离子掺杂诱导与调控BiFeO3结构相变、物性变化研究的现状。

Under room temperature,multiferroic material BiFeO3 has attracted considerable attentions during the past decade,and more and more fantastic physical properties of the compound have been discovered.The status quo of the re-search on the structural transitions and modulation of physical properties through A-site rare-earth doping is presented in this paper.