Finite element modeling of nanocomposite magnets

Finite element modeling treats magnetization processes within the framework of micromagnetic theory, taking into account the complex microstructure of a magnet. The numerical integration of the Gilbert equation of motion provides the time evolution of the magnetization and thus shows how reversed domain nucleate and expand. The numerical results of static micromagnetic calculations reveal the influence of the intrinsic magnetic properties on the remanence and the coercive field of nanocomposite Nd2Fe14B/alpha-Fe/Fe3B magnets. An increase of the hard phase anisotropy of only 8% increases the coercive field from 340 kA/m to 450 kA/m in two phase Nd2Fe14B/alpha-Fe magnets. This effect becomes less pronounced with increasing Fe3B content. In two phase Nd2Fe14B/Fe3B, the reduction of the soft phase magnetization and/or the soft phase exchange constant leads to an improvement of the coercive field without a significant loss in remanence. The magnetostatic interactions between the magnetic particles of bonded, nanocomposite magnets slightly reduce the remanence and the coercive field.