LIGHT-SCATTERING INVESTIGATIONS OF MAGNETIC ANISOTROPIES IN ULTRATHINEPITAXIAL CO FILMS

Using Brillouin light scattering, the properties of magnetic anisotrop ies in ultrathin epitaxial Co films grown on single-crystal Cu substra tes are investigated. All relevant magnetic anisotropy contributions a re determined, in situ in an ultrahigh vacuum system for the (001)-ori ented films, as well as ex situ for other film orientations, which are covered with a Cu cap layer. For (001)-oriented films we find a large in-plane anisotropy contribution of fourfold symmetry. For this contr ibution the volume and the surface part cancel to zero at the same thi ckness as found for the onset of ferromagnetic order. This finding is indicative for a stabilization of ferromagnetic order in Co/Cu(001) by in-plane anisotropy contributions. In (1113)-oriented films, Which ar e composed of (001)-terraces aligned along the [110BAR]-direction and spaced by 6.5 atomic distances, an additional uniaxial in-plane anisot ropy contribution is found which is identified as being of magneto-ela stic origin. For (110)-oriented films three ranges of thickness depend ence of the in-plane and out-of-plane anisotropy contributions are fou nd which correlate in the thin-film regime with the growth properties. (111)-oriented films show a linear dependence of the perpendicular an isotropy on the reciprocal film thickness over the full investigated t hickness range of 2 to 20 angstrom.