Systematic investigation of surface acoustic wave-driven ferromagnetic resonance: Model and simulation

A theoretical model is presented to describe the surface acoustic wave-driven ferromagnetic resonance (SAW-FMR), systematically and effectively explaining the results of the previous experiment. In our model, the precessional cone angle δθ and the power attenuation ΔP are employed to represent the intensity of FMR. The expression of δθ can be divided into three independent parts: a constant term, a frequency-dependent term, and a surface acoustic wave (SAW) equivalent field term; each part is expressed explicitly with various parameters. To deeply understand the special field-sweeping SAW power attenuation spectrum patterns observed in previous experiments, we creatively interpret δθ as a combination of the resonant frequency f0 spectrum and SAW equivalent field |sin⁡(2φM)| spectrum. It is the distinctive SAW equivalent term |sin⁡(2φM)| that makes SAW attenuation spectrum an incomplete pattern compared to traditional electromagnetic wave (EMW). Furthermore, we discuss the influence of multiple factors on the SAW-FMR, including the external magnetic field magnitude and direction, SAW frequency and amplitude, as well as the magnetocrystalline anisotropy direction and distribution. To validate our theoretical model, micromagnetic simulations are also carried out in the corresponding situations.