Imaging mechanisms of force detected FMR microscopy

We demonstrate spatial resolution of ferromagnetic resonance in a microscop ic sample of YIG using ferromagnetic resonance force microscopy (FMRFM). Me asurements were performed on a small single crystal YIG film grown on a GGG substrate, roughly rectangular in shape 20 mu mx similar to 150 mu m and 3 mu m thick. The perpendicular and parallel force geometries of FMRFM, in c onjunction with an external bias field both parallel and perpendicular to t he film, were used to scan the sample. This enabled the detection of strong signals, even at atmospheric pressure and room temperature. The fundamenta l and higher-order magnetostatic modes were observed to have 26-29 Gauss se paration. The intensity of these modes exhibited spatial variation as the m agnetic tip was scanned over the sample, and this behavior is qualitatively explained by DE theory. An improved fabrication method for magnet on canti lever was employed, which yielded a spatial resolution of 15 mu m. These re sults demonstrate the potential of FMRFM for investigating the spatial depe ndence of ferromagnetic resonance, and for studying the anisotropy fields a nd exchange coupling effects within multilayer films and small magnetic sys tems. (C) 2000 American Institute of Physics. [S0021-8979(00)80608-8].