NOVEL PERMANENT MAGNETIC-MATERIALS

被引:49
作者
COEY, JMD
机构
[1] Department of Pure and Applied Physics, Dublin, Trinity College
关键词
D O I
10.1088/0031-8949/1991/T39/002
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Materials for high-performance permanent magnets must have a high Curie temperature, a large spontaneous magnetization and strong uniaxial magnetocrystalline anisotropy. Binary rare earth iron intermetallics are deficient in one or more of these respects. New series of rare-earth intermetallic compounds may be generated from existing series by a process known as gas-phase interstitial modification, whereby interstitial atoms such as nitrogen or carbon are introduced into the structure by reaction of a powder of the intermetallic with an appropriate gas. The interstitials occupy sites adjacent to the rare earth, thereby creating a crystal field that reflects the new local symmetry. They also expand the lattice, which greatly enhances the Fe-Fe exchange interactions, and may increase slightly the iron moment. These effects are discussed in detail for four systems, R2Fe17N3-delta, R2Fe17C3-delta R(Fe11 Ti)N1-delta and R(Fe11 Ti)C1-delta (R = rare earth), all of which include compounds with potential for making new permanent magnets.
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页码:21 / 28
页数:8
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