Anisotropy and pinning field in nanocomposite magnetic materials

The pinning fields of domain wall at different grain boundary H0H0 have been calculated based on the given expression of anisotropy at grain boundary. The coercivity of nanocomposite magnetic materials is thought to be determined by H0H0. Compared with the experiential formula of coercivity, the expression of exchange–coupling coefficient αex corresponding to pinning fields on grain size DD was given too. The results showed that H0H0 and αex increase rapidly first, then increase slowly with increasing DD. Our results are consistent with the relative theoretical and experimental results given by others.