Observation of internal interfaces in) alloy films: A likely cause of perpendicular magnetic anisotropy

X-ray-absorption measurements of the local structure about Pt and Co in thin polycrystalline (Formula presented)(Formula presented) alloy films, which exhibit perpendicular magnetic anisotropy, indicate that the gross structure is fcc. However, the data reveal a directional anisotropy in the number of Co-Co bonds with an excess of Co-Co bonds in the film plane, consistent with two-dimensional clustering of Co. The resulting internal interfaces are analogous to those in Co/Pt multilayers suggesting a similar mechanism for the perpendicular magnetic anisotropy in these alloys. © 1996 The American Physical Society.