ANGULAR-DEPENDENCE AND COMPETITION OF COERCIVITY MECHANISMS

On the basis of simple model assumptions numerical results for the angular dependence of the coercivity of texturized hard magnets are presented. The models include 3 free parameters, describing the anisotropy of the single particles, the magnetic texture of the polycrystalline sample and an empirical parameter in relation to the coercivity mechanism. The 4 considered computing models are the Stoner-Wohlfarth theory, wall pinning, nucleation and surface softening processes. The numerical results are compared with room temperature measurements on NdFeB based polycrystalline samples with different hardness and different degree of alignment. It can be shown that the experiments disagree with the usual nucleation model and favour a particle surface softening mechanism in that material.