Characterization of CoPt-based granular media with intergranular magnetic interaction by Q-band ferromagnetic resonance

摘要

The influence of inter-granular exchange coupling (J_g) between columns and the magnetic anisotropy field (H_k) distribution (ΔH_k) on the ferromagnetic resonance (FMR) of the magnetic nano-column assembly is numerically investigated using the Landau-Lifshitz-Gilbert equation. The nano-column assembly is assumed to represent granular perpendicular magnetic recording (PMR) media. The FMR measurements of the PMR media with J_g > 1 erg/cm~2 can be used to evaluate the intrinsic values of H_k and the damping constant (α) despite the existence of ΔH_k. In case of PMR media with J_g = 0 erg/cm~2, the intrinsic value of α can be evaluated. However, H_k will be underestimated depending on the degree of ΔH_k.