Ferromagnetic Resonance in Amorphous and Nanocrystalline Materials

Abstract

Ferromagnetic resonance (FMR) has been demonstrated to be one of the most powerful techniques in the study of magnetic properties of materials. This technique has been applied to the whole range of known ferromagnetic materials, including bulk solids, thin films, magnetic multilayers, granular materials and fine particle systems. Despite this, the use of FMR in amorphous and nanocrystalline materials has been rather limited. These systems are rather complex and typically involve the presence of two interacting ferromagnetic phases. A general theory of ferromagnetic resonance will be presented for multiphase systems, including interactions. This theory will then be applied to experimental studies of the FINEMETs and FeZrCuB systems. These studies have been made as a function of annealing temperature and hence the nanocrystalline state of the samples. It will be shown that, in general, it is necessary to use a two phase model for FMR in these systems.