Approach to magnetic losses and their frequency dependence in Mn–Zn ferrites

The frequency dependence of the magnetic energy losses in sintered Mn–Zn ferrites is predicted from the quasistatic regime to the megahertz range. The predicting model is based on the appraisal of the contributions by domain wall (dw) displacements and magnetization rotations and the related relaxation-resonant-type dissipation mechanisms. Eddy currents are demonstrated to play little to negligible role. The frequency dependence of the dw generated losses is calculated from knowledge of the quasistatic losses, whereas the contribution by rotations is obtained via the Landau-Lifshitz-Gilbert equation, assuming distributed anisotropy fields. The model excellently applies to the frequency response of commercial ferrites.