Perpendicular magnetic anisotropy in CoPt3(111) films grown on a low energy surface at room temperature

Epitaxial (111)-oriented CoPt3 films were deposited on WSe2(0001) substrates at room temperature using molecular beam epitaxy. We observed strong growth induced uniaxial perpendicular magnetic anisotropy which has a maximum of 3.2×106 erg/cm3 and coercivity of about 200 Oe for films with thicknesses <6 nm. At a thickness larger than 6 nm the easy magnetization axis progressively rotates into the plane of the film as the film thickness is increased. The magnetic domain structure in films with perpendicular magnetic anisotropy was investigated by photoemission electron microscopy revealing a characteristic thickness dependence near the reorientation transition.