Anisotropy of grain in nanoscaled magnetic materials

摘要

The inter-grain exchange-coupling interaction and the anisotropy of grain in nanoscaled magnetic materials have been studied by putting forward an expression of anisotropy at grain boundary, K_1~(ij)(r), suitable for different coupling conditions. The value of anisotropy at grain interface K_1~(ij)(0) has a great effect on < K~(ij) > , especially on the average anisotropy of soft-hard phase grains < K > . When K_1~(sh)(0) is smaller, the effect of the hard grain on the anisotropy of soft grain is weak, and < K > increases monotonously with increasing D. When K_1~(sh)(0) is larger, the effect of the hard grain on the anisotropy of soft grain is strong, and < K > appears maximum at a certain grain size. When the value of K_1~(ij)(0) is in a certain range, the calculated variations of anisotropy with D are consistent with that of coerciyity given by other authors.