Buffer Induced Magnetic Patterning of Ultrathin Co Layer

The possibility of magnetic anisotropy engineering of ultrathin Co films in the scale of several dozen nanometers is investigated by magnetooptical magnetometry. In Au/Co/Au sandwiches the spin reorientation transition from the out-of-plane to the in-plane configuration is observed, when Co layer thickness exceeds 1.9 nm. Molybdenum as the underlayer suppresses the Co thickness range for which the perpendicular magnetization is stable. The application of patterned buffer in the form of Au islands grown on Mo layer for ultrathin Co film gives rise to the array of spatially stable magnetic dots fabrication ca. 100 nm in lateral size with magnetization perpendicular to the film plane surrounded by the area magnetized in the sample plane. PACS numbers: 75.70.−i, 75.30.Gw, 75.75.+a, 68.37.Ps, 78.20.Ls 1