Numerical analysis of successive ballistic rotations of magnetization caused by an application of sinusoidal magnetic fields

The magnetization reversal in a single-domain magnetic particle caused by a sinusoidal hard-axis field has been numerically studied for its application to magnetic random-access memories. The switching properties are analyzed as functions of the amplitude and frequency of the sinusoidal field. A sinusoidal field with a frequency higher than the magnetization relaxation frequency can induce successive ballistic trajectories of magnetization, which causes a large rotation surmounting the hard-axis direction. By choosing an appropriate frequency, it is found that the switching current amplitude can be reduced to one-fifth that of the static Stoner condition.