Oxygen-assisted room-temperature deposition of CoPt3 films with perpendicular magnetic anisotropy

Abstract

Trace amounts of oxygen in the deposition environment are shown to induce perpendicular magnetic anisotropy and remanence in nominally cubic CoPt3 grown by vapor deposition at or slightly above room temperature. Oxygen is known to act as a surfactant during epitaxial growth of Pt, and here is shown to affect the surface roughness of CoPt3 films. The dependence on oxygen partial pressure and on growth temperature suggest that the oxygen may act to increase the surface mobility of the growing films, thereby enhancing the clustering which leads to anisotropy. A strong orientation dependence in the anisotropy is found, which was not seen in the absence of oxygen. CO by contrast uniformly reduces anisotropy.