Thickness dependence of microstructures and magnetic properties for CoPt/Ag nanocomposite thin films

Ag underlayer (30nm) has improved the degree of ordering and perpendicular magnetic anisotropy of CoPt films (7.5–10nm). After annealing at 600°C and 700°C, the perpendicular coercivity of CoPt/Ag films has been raised as the thicknesses of CoPt layers are increased. The magnetic easy axis of CoPt/Ag films would change from a random orientation to an out-of-plane orientation. It is found that Ag underlayer with thickness of 30nm can improve the perpendicular magnetic properties of CoPt layers with thicknesses in the range of 7.5–10nm. The CoPt/Ag films would be a candidate for perpendicular magnetic recording media.