Microwave-Assisted Magnetization Reversal for Granular Media by a Resonant Cavity Method

Microwave-assisted magnetization reversal was verified by a cavity method with intention to apply homogenous microwave to a millimeter-size CoPtCr-SiO2 medium. By applying 34 GHz microwave with various power, magnetization reversal of the medium was assisted. The amount of the reversal magnetization was estimated using an internal magnetic field evaluated with ferromagnetic resonance (FMR) field. As a result, it is found that: 1) when the incident angle of external field is set at 90° (perpendicular), assisting effect depends on microwave power and magnetization of the media; 2) mode value of switching field distribution of the media was reduced 300 Oe by 160-mW microwave assisting; and 3) when the incident angle of external field is set at 45° during the microwave assisting, dispersion of the SFD decreased with increasing microwave power.