High-coercivity CoPt alloy films grown by sputtering

Co/sub x/Pt/sub 1-x/ alloy films (x=0.2/spl sim/0.4) were prepared by rf sputtering at substrate temperatures 150/spl sim/300/spl deg/C without a Pt underlayer and post annealing. The magnetic properties of the films showed strong dependence on the composition and substrate temperature. High coercivity (/spl sim/191 KA/m) and saturated remanence were achieved at conditions x=0.25 and 200/spl deg/C. In contrast to the previous observations, the high perpendicular magnetic anisotropy, in the current case, appeared not associated with the good CoPt (111) texture. An interpretation based on minor composition modulation in the films was proposed.