Influence of the deposition angle on the magnetic anisotropy in thin Co films on Cu(001)

Off-normal molecular beam epitaxy of Co on Cu(001) has been found to result in a uniaxial magnetic anisotropy. The easy magnetization axis is perpendicular to the plane of incidence for deposition angles between 10° and 80°. The uniaxial magnetic anisotropy is related to the formation of a uniaxial surface morphology during off-normal growth. Spot profile analysis low-energy electron diffraction measurements reveal the presence of elongated adatom structures in contrast to square ones growing at normal incidence. The long sides of the adatom structures are oriented perpendicular to the plane of incidence, i.e., parallel to the easy magnetization axis. The formation of elongated adatom structures is due to steering. Steering originates from long-range attractive forces between incident atoms and substrate atoms and leads to preferential arrival of atoms on top of adatom structures.