Microwave-assisted magnetization reversal in 0.36-μm -wide Permalloy wires

Microwave-assisted magnetization reversal in a 0.36 μm wide Ni80 Fe20 wire with a natural ferromagnetic resonance frequency of 8.42 GHz was investigated experimentally. Magnetization switching could be detected from a discontinuous change in the ferromagnetic resonance frequency of the wire. The application of microwaves with a frequency of 7.5 GHz and a power of 19.2 dBm reduced the switching field from 217 to 142 Oe. While high-power microwave-assisted switching reduced the dc switching field, it substantially broadened the switching field distribution. This is mainly attributed to inhomogeneous resonance properties of the nucleation sites in the wire.