The Study Of Spin Wave Resonance Frequencies In Magnetic Thin Films Under Next Nearest Neighbor Interaction

The effects of next nearest neighbor(NNN)interaction,nearest neighbor(NN)interaction,surface anisotropy,film thickness,symmetry,interface coupling and external magnetic field on spin wave resonance(SWR)frequency in the ferromagnetic single/bilayer film were investigated by using linear spin wave approximation and Green's function method.It is found that the SWR frequencies are enhanced by considering NNN interaction,external magnetic field,NN interaction,and surface anisotropy.As the film thickness increases,the resonance frequencies of the energetically higher modes shift to higher value,and the gap of frequency starts to be broadened.For ferromagnetic bilayer films,interface coupling contribute to the improvement of SWR frequency.The symmetry has a little effect on energetically lowest mode,in other words,the resonance frequency of the energetically lowest mode is slightly increased,and the weak symmetry,making a small contribution to the wide band gap.In addition,the NNN interaction is ineffective on SWR frequency without surface anisotropy.The impact of the surface anisotropy on thinner film is enormous.It's worth noting that resonance frequency of energetically higher modes have exhibited similar phenomenon under certain circumstances;moreover,there aresome special cases for the inflection points in the modes,and resonance frequencies are hastily increases.