Spin-wave resonance frequency in ferromagnetic thin film with the next nearest neighbor interaction

Linear spin-wave approximation and Green?s function were used to study the dependence of spin wave resonance (SWR) frequency in a ferromagnetic film considering the external magnetic field, surface anisotropy, number of atomic layers, nearest and next nearest neighbor interaction. A systematic study of the SWR frequency as a function of external magnetic field, surface anisotropy, and next nearest neighbor interaction was performed. It demonstrates that the next nearest neighbor interaction affects strongly on the SWR frequencies of energetically higher modes, as well as the gap of resonance frequency between the highest and lowest energy modes is broaden as the next nearest neighbor interaction increasing. Moreover, we show that SWR frequencies at two higher energy modes are coincided when the surface anisotropy increases. Finally, as the thickness of film decreases, SWR frequency of the lowest energy mode is shifted to higher value. Thus, considering these effects in an opportune way, we are able to control the SWR frequency of the system.

Automated summary

In this study, the dependence of spin wave resonance (SWR) frequency in a ferromagnetic film on external magnetic field, surface anisotropy, number of atomic layers, nearest and next nearest neighbor interaction was investigated using linear spin-wave approximation and Green’s function. It was found that next nearest neighbor interaction significantly affects the SWR frequencies of energetically higher modes, and the gap between the highest and lowest energy modes increases with the next nearest neighbor interaction. Additionally, the frequencies of two higher energy modes coincide with increasing surface anisotropy, and the SWR frequency of the lowest energy mode shifts to a higher value as the film thickness decreases. By considering these effects, the SWR frequency of the system can be controlled effectively.