The magnetism and morphology of thin Ni films deposited on the Cu(110)-Cu(110)-$(2\times 1)$O surface (Cu-CuO stripe phase) have been studied by scanning tunneling microscopy (STM) and reflectance difference magneto-optical Kerr spectroscopy (RD-MOKE). The magnetic easy axis of the Ni films lies completely in plane up to a coverage of 22.5 ML. Exceeding this coverage, a small remanent magnetization component pointing out of plane evolves. Upon postgrowth oxygen exposure the Ni film becomes completely out-of-plane magnetized and the out-of-plane remanence and coercive field strongly increase during exposure. STM images reveal a fully $(2\times 1)$O reconstructed topmost Ni layer after the oxygen exposure, but no morphological changes of the Ni film. We thus conclude that the oxygen-induced surface reconstruction strongly modifies the magnetic properties of the Ni film by enhancing the surface magnetic anisotropy.

• Received 3 August 2011

DOI:https://doi.org/10.1103/PhysRevB.85.014423