Magnetic properties of Ag/Co/Pt(1 1 1) ultrathin films

The magnetic anisotropy of Ag/Co/Pt(1 1 1) ultrathin films was studied by the surface magneto-optic Kerr effect. Some interesting magnetic properties were observed. The location of Ag atoms on Co sites seems to prevent the spin reversal of Co. The saturated magnetization is not significantly changed after Ag ultrathin films are deposited on the Co/Pt(1 1 1) surfaces. The Curie temperatures increase after the Ag ultrathin film deposition. During thermal annealing, the out-of-plane magnetization in the Ag capped films is enhanced dramatically. The structural changes and the evolution of the chemical composition at the interfaces during the annealing were studied by low-energy electron diffraction and Auger electron spectroscopy, respectively. The giant enhancement of the out-of-plane magnetization is due to the formation of Co-Pt alloy and Ag overlayer improving the interface structure.