CONTINUOUS EVOLUTION OF THE INPLANE MAGNETIC ANISOTROPIES WITH THICKNESS IN EPITAXIAL FE FILMS

We have studied the evolution of the magnetic in-plane anisotropy in e pitaxial Fe/GaAs films of both (001) and ((1) over bar 10) orientation as a function of the Fe layer thickness using the longitudinal magnet o-optic Kerr effect and Brillouin light scattering. Magnetization curv es which are recorded in situ during film growth reveal a continuous c hange of the net anisotropy axes with increasing film thickness. This behavior can be understood to arise from the combination of a uniaxial and a cubic in-plane magnetic anisotropy which are both thickness dep endent. Structural analysis of the substrate and Fe film surfaces prov ides insight into the contribution of atomic steps at the interfaces t o the magnetic anisotropy. Changing the degree of crystalline order at the Fe-GaAs interface allows us to conclude that the magnetic anisotr opies are determined by atomic scale order. (C) 1996 American Institut e of Physics.