Micromagnetic modelling and magnetization processes

Abstract

Micromagnetics is a continuum theory to describe magnetization processes on a length scale which is large enough to replace the atomic spins by a continuous magnetization vector and small enough to resolve the magnetization transition inside a domain wall. Depending on the magnetocrystalline anisotropy the characteristic length scale, the domain wall width or the minimum discretization size, is in the order of several nanometres to micrometres. Typical examples for numerical micromagnetic simulations are shown, where the role of a granular microstructure and precipitates on hysteresis properties is significant, such as in FePt nanocrystals, granular CoCrPtX thin films for longitudinal magnetic recording and modern bulk rare earth permanent magnets.