Topology-dependent interface contribution to magneto-optical response from ultrathin Co films grown on the (001), (110), and (111) surfaces of Pd (Article No. 085413)
Abstract
We have grown ultrathin epitaxial Co films on three low-index surfaces of Pd. Their magnetic properties studied by the magneto-optical Kerr effect were correlated with the surface morphology analyzed by scanning tunneling microscopy.
A perpendicular magnetic anisotropy in the films appeared after exposure to residual gas at low temperature, after coverage with an Au overlayer or after annealing at 370 K and above. For one- and two-monolayer-thick films the hysteresis loops are reversed with respect to those of thicker Co films.
This is due the negative polar Kerr rotation contribution from the Co/Pd interface dominating over the positive polar Kerr rotation contribution from the non-interface part of the Co film. Reversed loops are not seen when the Co films grow in a three-dimensional mode.
This indicates a clear correspondence between the mode of growth and the magneto-optical response. The results qualitatively agree with the available band-structure calculations for the Co/Pd multilayers.