Spin Engineering in Ultrathin Cu/Co/Cu(110)

We have studied the effect of depositing Cu overlayers onto CO gas dosed Co/Cu(110) ultrathin films $(6<\mathrm{}{d}_{\mathrm{Co}}<30\mathrm{}\mathrm{monolayers})$. We find that submonolayer Cu coverages can completely reverse the in-plane 90° easy axis switch caused by the CO adsorption for all Co thicknesses studied and for sufficiently thick Co films $(d_{\mathrm{Co}}>15\mathrm{}\mathrm{monolayers})$. This enables us to “controllably engineer” the direction of the easy axis at a constant Co thickness.