高性能La-Co共替代M型永磁铁氧体的磁各向异性增强机理研究进展

Research progress of magnetic anisotropy enhancement mechanism of high-performance La-Co co-substituted M-type permanent magnet

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摘要自20世纪末以来,La-Co共替代的M型铁氧体备受关注,已成为高性能永磁铁氧体的基础材料.Co2+的未淬灭轨道矩被认为是增强铁氧体单轴各向异性的原因,但其微观作用机理尚未完全解释清楚.为了满足铁氧体材料日益增长的性能需求,理解其磁各向异性增强机理至关重要,并寻求从根源上的提升、低成本和高效的方法,以制定开发高性能产品的指导原则.本文综述了一系列研究工作,旨在确定Co离子在晶格中的取代位置,这是增强磁各向异性的关键.这些研究为进一步提高永磁铁氧体的磁性能提供了重要的材料设计参考. La-Co co-substituted M-type ferrite,which was first reported at the end of the 20th century,as the cornerstone of high-performance permanent magnet ferrites,has received increasing attention from researchers around the world.The unquenched orbital moments of Co2+play a pivotal role in enhancing the uniaxial anisotropy of M-type ferrites.However,a comprehensive understanding of its microscopic mechanism remains elusive.In order to meet the increasing performance requirements of ferrite materials,it is imperative to clarify the mechanism behind the enhancement of magnetic anisotropy,and at the same time seek the guiding principles that are helpful to develop high-performance product quickly and economically.But its mechanism at a microscopic level has not been explained.This review comprehensively analyzes various studies aiming at pinpointing the crystal sites of Co substitution within the lattice.These investigations including neutron diffraction,nuclear magnetic resonance,and Mössbauer spectroscopy can reveal the fundamental origins behind the enhancement of magnetic anisotropy,thereby providing valuable insights for material design strategies aiming at further enhancing the magnetic properties of permanent magnet ferrites.The exploration of co-substitution sites has yielded noteworthy findings.Through careful examination and analysis,researchers have discovered the complex interplay between Co ions and the lattice structure,revealing the mechanisms of enhanced magnetic anisotropy.The current mainstream view is that Co ions tend to occupy more than one site,namely the 4f_(1),12k,and 2a sites,all of which are located within the spinel lattice.However,there have also been differing viewpoints,implying that further exploration is needed to uncover the primary controlling factors influencing Co occupancy.It is worth noting that the identification of specific Co substitution sites,especially the spin-down tetrahedron 4f_(1),has achieved targeted modifications,ultimately finetuning the magnetic properties with remark

作者刘若水王利晨俞翔孙洋何诗悦赵同云沈保根 Liu Ruo-Shui;Wang Li-Chen;Yu Xiang;Sun Yang;He Shi-Yue;Zhao Tong-Yun;Shen Bao-Gen(Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China;Beijing State Key Laboratory of Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;Ganjiang Innovation Research Institute,Chinese Academy of Sciences,Ganzhou 341119,China;School of Rare Earths,University of Science and Technology of China,Hefei 230026,China)

机构地区中国科学院宁波材料技术与工程研究所中国科学院物理研究所中国科学院赣江创新研究院中国科学技术大学稀土学院