FIELD AND FREQUENCY DEPENDENCES OF MONODOMAIN AND MULTIDOMAIN MICROWAVE-ABSORPTION IN MAGNETIC-FILMS

We report both experimental and theoretical results concerning the app lied de field dependence of microwave absorption on mono and multidoma in structures. Especially, we are interested in the low-field region w here this absorption is due to the domain mode ferromagnetic resonance (DM-FMR) phenomenon. The sample supporting parallel stripe domains is a rare earth bismuth-substituted single-crystal garnet film. We study the variation of DM-FMR microwave power absorption as a function of t he strength of the de field applied in the domain wall plane inside th e frequency range 6-11 GHz using a highly sensitive FMR spectrometer. The power absorption spectra Pa(H) present complex shapes in the low-f ield region with one or two peaks. Tile experimental results are analy zed by adopting the formalism of Smit and Beljers. This model seems in adequate to describe precisely the whole observed behaviours and such a discrepancy will be discuss.