Unusually Large Magnetic Anisotropy in Electrochemically Deposited Co-Rich Co-Pt Films

Co-rich Co-Pt films grown by electrodeposition from an amino-nitrite/citrate/glycine electrolyte onto Au(111) substrates apparently grow with a hexagonal structure, with its c-axis directed perpendicular to the surface. The films exhibit a perpendicular magnetic anisotropy (MCA) of the same order of magnitude as the shape anisotropy. Experimental estimates of the MCA result in a higher anisotropy than that reported for bulk materials of the same composition, but similar to values measured in films grown by vacuum methods at relatively high temperature, which partly consist of a high anisotropy, metastable orthorhombic Pmm2 phase. Comparison of valence band X-ray photoelectron spectroscopy measurements on electro-deposited films with density functional theory simulations of the electronic structure of the various reported Co3Pt structures support the notion that the films may consist of a mixture of the hexagonal and the Pmm2 structure.