Magnetic anisotropies and dispersion relation of epitaxial Fe/InAs(001) films

Magneto-transport effects investigated for the application in some hybrid structures need also a careful magnetic characterization. In our studies the angular dependence of the uniform mode excited in ferromagnetic resonance was measured at various frequencies for epitaxially grown Fe films on a semiconducting InAs(001) substrate. The results enable a precise determination of the magnetic anisotropies in this system. A large out-of-plane twofold anisotropy (K2⊥=2.8×106 erg/cm3) and an in-plane fourfold anisotropy (K4∥=0.51×106 erg/cm3) were found. The latter appeared to be modulated by a small uniaxial term with the easy axis rotated by 45° with respect to the [100] direction, the easy axis of the fourfold anisotropy. Based on multi-frequency measurements the dispersion relation has been verified, i.e. the resonance field versus the microwave frequency has been plotted and compared with calculations.