Micromagnetic Studies on the Coercive Force of Hard Magnets Using a One-Layer Defect Model

The coercive forces of hard magnets are calculated using a one-layer defect model based on micromagnetism. Nucleation processes are classified into three types depending on the defect parameters. For certain values of the parameters, the nucleation field has a minimum value. The origin of the decreasing coercive force and a method for increasing the coercive force are also discussed.