Ferromagnetic Resonance Of Magnetic Thin Film

Resonance frequency and resonance magnon density of two-layer and three-layer magnetic superlattice thin films with quantum Green-function method have been studied in this paper. The effect of temperature, interlayer exchange coupling, anisotropy, external magnetic field and damping on resonance frequency and resonance magnon density of magnetic thin film have been analyzed. And the relationship between resonance frequency and resonance magnon density is studied.The results show that, number of the resonance peak of magnetic thin film is same as the layer number of film. The interlayer exchange coupling can only affect the resonance peaks of the sublayer connected by the coupling, and the resonance frequency of the magnetic thin film increases with increasing interlayer exchange coupling, while the resonance intensity decreases with incersing interlayer exchange coupling. At low temperature, the anisotropy can only affect the resonance frequency and resonance intensity of the corresponding sublayer, and the frequency increases while the resonance intensity decreases with increasing anisotropy. At high temperature(close to transition temperature), the anisotropy of a sublayer can not only affect the resonance peak of the corresponding sublayer, but there is also a weak effect on the resonance peaks of other sublayers. When the external magnetic field is enhanced, for the twolayer superlattice thin film, the resonance frequency of one resonance peak increases while the corresponding resonance intensity decreases, and the resonance frequency of the other resonance peak decreases while the corresponding resonance intensity increases; for the threelayer superlattice thin film, the resonance frequencies of two resonance peaks increase while the corresponding resonance intensities decrease, and the resonance frequency of the other resonance peak decreases while the corresponding resonance intensity increases. The higher the temperature is, the smaller the resonance frequency of resonance peak of thin film is, but the higher the corresponding resonance intensity is. When the damping increases, the resonance frequency do not change, but the resonance intensity decreases and the resonance linewidth increases.The resonance frequency of the thin film can be improved while the resonance intensity can be decreased by increasing the anisotropy or interlayer exchange coupling of the thin film; it can improve the resonance intensity while reduce the resonance frequency by raising the temperature. It can be achieved to obtain thin film having both high resonance frequency and high resonance intensity by increasing the temperature, interlayer exchange coupling and anisotropy.