Growth induced magnetic and chemical anisotropy in CoPt₃ alloy films

We report the results of polarized Co $K$ EXAFS experiments on a series of CoPt₃ films grown by molecular beam epitaxy on (100) MgO single crystal substrates over a range of temperatures from 473 K to 1073 K. These samples exhibit substantial perpendicular magnetic anisotropy that is strongly dependent on the substrate growth temperature T_g. We measure a preference for in-plane Co-Co pairs that is correlated with the magnetic properties.