Anisotropy at nano-grain boundary and effective anisotropy between magnetically soft and hard nano-grains

An expression of anisotropy at grain boundary suitable for different coupling conditions has been given, based on which the effective anisotropy between soft and hard grains < K-sh > has been calculated in nanoscaled magnetic materials. The results showed that < K-sh > increases rapidly first, then the increase becomes slow, and < K-sh > decreases with increasing D-s for the same value of D-h. < K-sh > decreases with increasing D-s for all given D-h, and the decrease rate becomes slow with increasing D-h. In order to obtain higher effective anisotropy between magnetically soft and hard grains, D-h should not be less than 25 nm, and D-s should be about 10 nm. (c) 2007 Elsevier B. V. All rights reserved.