Microwave-assisted switching of NiFe magnetic microstructures

We have calculated by either macrospin analytical method or micromagnetic numerical solving the microwave-assisted switching of a small rectangular platelet as a function of the amplitude and the frequency of a microwave excitation field. The spectral analysis of this phenomenon reveals that microwave-assisted switching is optimal for a rf slightly lower than the linear magnetic resonance frequency measured at low level. Similar experimental results, obtained on 100 μm scale NiFe structures, reveal the same tendency. Switching time for such a process was obtained from calculations that show that subnanosecond switching times require combinations of large dc and rf magnetic fields.