Magnetization dynamics and relaxation in epitaxial FePd thin films with a stripe domain structure

FMR investigations on epitaxial partially ordered FePd thin films with a pe rpendicular magnetic anisotropy (PMA) are presented. The measurements have been performed over a wide frequency range (6-18 GHz) in the multidomain st ate where a weak-stripe domain structure exists. Parallel FMR measurements exhibit three magnetic excitations. Their dispersion curves, frequency vers us resonance field? and the frequency dependence of the related resonance l inewidths are reported. It is shown that the resonance fields and linewidth s increase with frequency. For the two main modes identified with domain mo des: these behaviors are correctly described by the Domain Mode Ferromagnet ic Resonance (DM-FMR) model. Especially, the DM-FMR field-swept linewidth e xpressions assuming a Landau- Lifshitz-Gilbert-type relaxation have been de rived and compared satisfactorily with the experimental data. The physical origin of tl-le third excitation is discussed in terms of domain wall and s pin-wave modes.