  We studied the microwave assisted magnetic reversal of 65 nm by 71 nm
elliptical Ni80Fe20 nanomagnets. Hysteresis curves were measured by
magneto-optical Kerr effect for a range of microwave frequencies and
amplitudes. The coercive field Hc was reduced by 26% for an rf field of 0.08Hc
when the microwave frequency coincided with the minimum of the experimentally
determined ferromagnetic resonance frequency with varying dc field. The
experimental results for the fractional reduction in Hc with rf field amplitude
are in good agreement with numerical simulations for an array of interacting
macrospins with a physically realistic shape anisotropy distribution
