Magnetization dynamics of buckling domain structures in patterned thin films

The magnetodynamics of lens-shaped thin-film elements are studied using vector network analyzer ferromagnetic resonance. A strong increase in the frequency at resonance is found when approaching the switching field. From magnetic force microscopy imaging the increase in resonance frequency is ascribed to the formation and evolution of a buckling domain state. The experimental data are qualitatively reproduced by micromagnetic simulations of a model element. Thereby, the roles of the external magnetic field and the buckling wavelength are extracted separately. Magnetic domain modes with dynamic magnetization modulations parallel and perpendicular to the static magnetization are identified. Based on magnetostatic energy considerations qualitative arguments are derived that allow for an interpretation of the dynamic response in such low-symmetry magnetization distributions.