Observation of microwave-assisted magnetization reversal in perpendicular recording media

Abstract

This letter reports microwave-assisted magnetization reversal (MAMR) in a 700-Gbit/in2 perpendicular media sample. The microwave fields were applied by placing a coplanar waveguide on the media sample and feeding it with narrow microwave pulses. The switching states of the media grains were measured by magnetic force microscopy. For microwaves with a frequency close to the ferromagnetic resonance (FMR) frequency of the media, MAMR was observed for microwave power higher than a certain threshold. For microwaves with certain high power, MAMR was observed for a broad microwave frequency range which covers the FMR frequency and is centered below the FMR frequency.