Uniaxial magnetic anisotropy of epitaxial Fe films on InAs(100)-4×2 and GaAs(100)-4×2

Abstract

The evolution of the uniaxial magnetic anisotropy of ultrathin epitaxial Fe films grown on InAs(100)-4×2 and GaAs(100)-4×2 has been studied in situ by means of the magneto-optical Kerr effect. In Fe/InAs(100)-4×2, the uniaxial magnetic anisotropy easy axis direction along [011] was found to be rotated 90° compared with that of Fe/GaAs(100)-4×2 along [01̄1]. Real-time reflection high energy electron diffraction measurements of Fe/InAs(100)-4×2 show that the lattice constant of the epitaxial Fe films relaxes remarkedly faster along the [01̄1] direction than along the [011] direction in the same thickness range where the uniaxial magnetic anisotropy occurs. These results suggest that the symmetry-breaking atomic scale structure of the reconstructed semiconductor surface gives rise to the uniaxial magnetic anisotropy in a ferromagnetic metal/semiconductor heterostructure via surface magneto-elastic interactions.