Determining wave vector and material property from the phase-shift of spin-wave propagation

Different to conventional ferromagnetic resonance methods, we use the phase-shift of spin-wave propagation to investigate spin-wave in conducting ferromagnetic thin films. Spin-wave wave vector (or wave number) k, a key parameter in the study of spin-wave dispersion and propagation, is extracted from the ratio of the phase-shift to the propagation distance and the ratio of the intercepts to the slopes of the plot of frequency square (f²) vs. the bias field (H). The wave vectors calculated by both methods are in good agreement. The in-plane anisotropy field H_k and saturation magnetization M_S can also be extracted from the phase-shift map.