Evaluation of Anisotropic Energy and -Factor of Fe(001) and Fe-Co(001) Single-Crystal Thin Films Using Broadband Ferromagnetic Resonance

A broadband inductive technique has been applied to measure static magnetic field dependence of resonant frequency for Fe(001) and Fe-Co(001) single-crystal thin films. Different dependences of resonant frequency are observed depending on the static magnetic field application direction between [100] and [110]. The phenomenon is analyzed using the Kittel's resonance formula. The calculated values obtained by using three fitting parameters of saturation magnetization, M_s, anisotropic energy, K₁, and g-factor show good agreements with the experiments for both crystal orientations of [100](easy axis) and [110](hard axis) for Fe(001) single-crystal thin film. The three fitting values are close to those of bulk single-crystal Fe. There is a discrepancy between experiment and calculation for the hard axis, [100], of Fe-Co single-crystal film. It is considered that magnetoelastic energy originating from large positive magnetostriction has some effect on the phenomenon observed for Fe-Co(001) thin films when measured along the hard magnetization axis.