Micromagnetic studies on magnetic spectra of submicron ferromagnetic particles with different aspect ratio

Two resonance modes occur when the magnetic spectra of rectangular ferromagnetic particles with different aspect ratio are studied using micromagnetic simulation. The intensity of the higher mode is stronger when the particles have the aspect ratio larger than 1.6. When the aspect ratio reduces to 1.6, only one strong resonance peak remains with some tiny satellite peaks appeared. These behaviors are attributed to the competition between the exchange interaction and dipolar coupling, which has different result in the edge and middle part, respectively.