Manifestation of granular structure in FMR spectra

The ferromagnetic resonance (FMR) method is used to study ferromagnetic powders dispersed in a diamagnetic solid matrix. We have investigated the fine structure observed against a background of wide structureless FMR lines, which are common for polycrystalline non-oriented specimens. According to the suggested model, the observed narrow lines appear in FMR spectra owing to jump changes in resonance conditions resulting from abrupt changes of the specimen magnetization with varying the outer magnetic field. It is shown that physical reasons of the magnetization jumps may be the magnetic interparticle interaction as well as the complex anisotropy of particles.