MAGNETIC-PROPERTIES OF COPT ALLOY-FILMS SPUTTERED ON PT UNDERLAYERS

CoPt alloy films have been sputtered on room-temperature glass slides. It has been found that effective perpendicular anisotropy K(perpendicular-to) depends on the film composition and reaches a maximum in films with M(s) is similar to 850 emu/cm3, and that K(perpendicular-to) is greatly enhanced by the application of substrate bias and the deposition of a Pt underlayer. K(perpendicular-to) increases with increasing CoPt layer thickness d (CoPt), becoming almost constant beyond d (CoPt) = 100 nm in films sputtered on 100-nm-thick Pt underlayers. It has also been found that sputtering at higher Ar gas pressure without substrate bias greatly enhances coercivity, though K(perpendicular-to) is somewhat reduced.