Theoretical and experimental permeability spectra of nano-granular Co-Fe-Al-O films for GHz magnetoelastic device applications

The effects of the various parameters such as saturation magnetization, anisotropy field, film thickness and resistivity of soft magnetic thin films on the permeability spectra are investigated by using the Landau-Lifshitz-Gilbert equation. Both effects of eddy current loss and ferromagnetic resonance loss on the intrinsic permeability are taken into account to obtain the expression for the effective relative permeability. The calculated permeability spectra are in good agreement with experimental results for nano granular Co-Fe-Al-O thin films, even though only one fitting parameter, the damping constant, is used.