Observation of ferromagnetic resonance in a microscopic sample using magnetic resonance force microscopy

We report the observation of a ferromagnetic resonance signal arising from a microscopic (similar to 20 mu m X 40 mu m) particle of thin (3 mu m) yttrium iron garnet film using magnetic resonance force microscopy (MRFM). The large signal intensity in the resonance spectra suggests that MRFM could become a powerful microscopic ferromagnetic resonance technique with a micron or sub-micron resolution. We also observe a very strong nonresonance signal which occurs in the field regime where the sample magnetization readily reorients in response to the modulation of the magnetic field. This signal will be the main noise source in applications where a magnet, is mounted on the cantilever. (C) 1996 American Institute of Physics.