Changes in magnetic properties of ultrathin cobalt films as induced by Mo, V, Au overlayers

Abstract Magneto-optical (based on polar and longitudinal Kerr effects) and FMR studies were carried out on ultrathin cobalt films deposited on Au(1 1 1) and covered with either a V or Mo cover layer, and finally by an Au protective layer. Co thickness at which the magnetization reorientation transition from an easy axis into an easy plane occurs is influenced by the type of cover layer. Even 0.1 nm thick V-coverage is efficient enough to induce full reorientation. A strong decrease of domain structure size (down to the submicrometer scale) was observed while approaching reorientation phase transition (RPT). The influence of a Mo-overlayer on Co in-plane magnetic anisotropy is shown to be much weaker in comparison to the influence of Mo-buffer.