Anisotropy of grain in nanoscaled magnetic materials

Abstract

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, K1ij(r), suitable for different coupling conditions. The value of anisotropy at grain interface K1ij(0) has a great effect on ⟨Kij⟩, especially on the average anisotropy of soft-hard phase grains ⟨K⟩. When K1sh(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 K1sh(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 K1ij(0) is in a certain range, the calculated variations of anisotropy with D are consistent with that of coercivity given by other authors.