INTERACTIVE AND COOPERATIVE MAGNETIZATION PROCESSES IN HARD MAGNETIC-MATERIALS

Magnetization processes in rare earth - transition metal intermetallic compounds in general have to be investigated within the framework of three different scales: (1) The atomistic level taking into account th e intrinsic magnetic properties of rare earth and transition metal ion s. (2) The nanomagnetic level taking into account perturbations of exc hange interactions and of the magnetic anisotropies in individual grai ns. (3) The micromagnetic level taking into account short range exchan ge interactions as well as long range dipolar interactions in ensemble s of grains. It is shown that a universal relation may be derived for the coercive field of permanent magnets as produced by sintering, melt -spinning or mechanical alloying.