Effective anisotropy between magnetically soft and hard grains in nanocomposite magnets

Effect of grain size on the effective anisotropy constant between magnetically soft (α-Fe) and hard (Nd2Fe14B) grains in nanocomposite magnets, 〈Ksh〉, has been investigated. The results show that the values of 〈Ksh〉 increase with decreasing size of soft grain, Ds, for the given size of hard grain, Dh. For the given Ds, 〈Ksh〉 increases with increasing Dh, and then approaches a steady value. In order to get a high value of 〈Ksh〉, the hard grain size should be larger than 30 nm and the soft grain size should be about 10 nm.