Calculation of the magnetization oscillation frequency in a nanostructured synthetic ferrimagnet

Abstract

Theoretical equations were derived for the resonance frequency of magnetization oscillation in a nanostructured synthetic ferrimagnet in the framework of a single domain model. The theoretical equations, which are applicable to various magnetization alignments including a spin flop, were then tested using a micromagnetic simulation in both the macrospin and microspin models. Excellent agreement was obtained between the results of the theoretical prediction and micromagnetic simulation in the macrospin model over the entire range of applied magnetic fields, confirming the validity of the theoretical equations derived in this study. The agreement between the results from the theoretical prediction and the micromagnetic simulation in the microspin model was not excellent, particularly in the acoustic mode, showing a substantial deviation from the ideal single domain behaviour. However, good agreement was obtained by decreasing the magnetization component in the thickness direction by 10% of that in the single domain state. This suggests that the magnetization deviates slightly from the single domain state as the magnetization moves out of the film plane during a magnetization oscillation.