Magnetic anisotropy strength and surface alloy formation in Mn/Co/Cu(001) overlayers

The correlation between the structure and magnetic properties of ultrathin Mn overlayers grown on fee Co/Cu(001) was studied using low-energy electron diffraction and the magneto-optic Kerr effect in situ. A two-dimensional m agnetic c(2x2) Mn-Co(001) surface alloy was found to be stabilized in the r ange 0.3-0.8 ML Mn overlayer thickness. Within this thickness range Mn is f erromagnetically coupled to the fee Co(001) underlayer. Above one monolayer of Mn, the c(2x2)surface reconstruction fully disappears and the Mn overla yers are no longer ferromagnetically ordered. Furthermore, it is shown that the Kerr signal, magnetic anisotropy strength, and coercivity are correlat ed with the stabilization of the MnCo surface alloy and growth conditions. [S0163-1829(99)02709-5].