Perpendicular magnetic anisotropy of multilayers: recent insights

Abstract Extending our understanding of perpendicular magnetic anisotropy (PMA) beyond the phenomenological approach of volume ( K V ) and interface anisotropies ( K S ) requires caution. Experimentally, many factors such as roughness, formation of interface alloys, or patchiness of ultrathin layers may cause a reduction in PMA. Where stresses are present in multilayer growth, these may, under particular circumstances, contribute to both K V and K S , as demonstrated for the Cu/Ni/Cu system. Theoretically, the difficulty in modelling incoherently grown materials prevents a detailed quantitative comparison with most experimental systems, so that an evaluation of the underlying approximations common to all of the quantitative theoretical studies becomes very difficult.