Numerical simulation of magnetization reversal in hard magnetic materials using a finite element method

Abstract

The presented numerical approach to coercivity analysis combines a nucleation model of coercivity with the finite element method. The simulation program offers the opportunity to investigate the effect of material properties, the microstructure and the orientation of the applied field on the coercivity of an ensemble of hard magnetic grains. The influence of grain alignment and non-magnetic intergranular phases on the angular dependence of coercivity confirms the coupling of grains by dipole interactions. The stray field interaction between misaligned grains explains the deviation of the angular dependence of the coercive field from its theoretical values. In hard magnetic materials the interplay between microstructure and material properties is responsible for the coercivity. Stray field terms and material constants represent the microstructure and the material properties in the micromagnetic equation. To calculate the magnetic stray field of a given microstructure a finite element program has been developed. An algorithm for automatic mesh refinement adapts the finite element mesh to the given microstructure.