MAGNETIC NANOPARTICLES AND MAGNETOCRYSTALLINE ANISOTROPY

The size dependent properties of monodomain ferromagnets are described . Following an introduction to the technical magnetics parameters used to describe bulk ferromagnets, the size dependence of these parameter s is described. Bulk ferromagnetic materials are generally described a s either hard or soft, depending on the value of their magnetocrystall ine anisotropy. The role of anisotropy in monodomain ferromagnets is i nvestigated through examination of two case studies: the high anisotro py alloy SmCo5, and a series of FexCo1-x alloys with very low anisotro py. Both dipolar and exchange interactions between particles are discu ssed, and the connection is made between isolated fine particles and c ompacted nanocrystalline materials. (C) 1997 Acta Metallurgica Inc.