Magnetization reversal by microwave in magnetic tunnel junctions

Microwave assisted magnetization switching was investigated using Fe30Co70/Al2O3/Ni80Fe20 magnetic tunnel junctions incorporated with a coplanar waveguide. Coercivity reduction (or switching field) of Ni80Fe20 layer was reduced with a microwave excitation. It was found that the coercivity reduction depends on both frequency and power of the microwave. The numerical simulation based on the Landau-Lifshitz-Gilbert equation reproduced the trend of the experimental data. The results indicate that microwave can be an efficient mean to switch the magnetization of a thin film.