Microwave-Assistance Effect on Magnetization Switching in Antiferromagnetically Coupled CoCrPt Granular Media

We examined microwave-assisted switching properties of an antiferromagnetically coupled (AFC) granular perpendicular medium consisting of CoCrPt–TiO2(5)/Co(0.7)/Ru(0.9)/Co(0.7)/CoCrPt–TiO2(3) (in nanometers). In a saturation remanent state, the magnetization of the lower CoCrPt–TiO2 + Co layer switched its direction to form AFC with that of the upper layer because of a thin-film thickness. We assessed the microwave-assistance effect on magnetization switching from the remanent state to the saturation state of the thick upper layer using an anomalous Hall effect. The reduction of a switching field was most enhanced by the application of microwaves of 10 GHz frequency. The switching field reduction by microwave assistance for the AFC medium, obtained by compensating a thermal agitation effect, was estimated as 26%.