Semi-implicit steepest descent method for energy minimization and its application to micromagnetic simulation of permanent magnets

To reveal the relationship between coercivity of permanent magnets and their microstructure, micromagnetics is one of the key technologies for analyzing the magnetization reversal mechanism. Especially, microscopic reversal process such as nucleation of a reversed domain and domain wall pinning has been investigated by micromagnetic simulation [1]. However, since the mesh size in the simulation should be less than the exchange length of a magnet to calculate the domain wall structure accurately, the overall dimensions of models for such simulation is practically limited to very small length scales. Therefore, further improvement in calculation speed are demanded to simulate reversal process of more realistic microstructure.