SURFACE-ENHANCED MAGNETIC-MOMENT AND FERROMAGNETIC ORDERING OF MN ULTRATHIN FILMS ON FCC CO(001)

We have grown ultrathin films of Mn on fcc Co(001) substrates and have investigated their magnetic properties using the element-specific techniques of soft-x-ray absorption (SXA) and x-ray magnetic circular dichroism (XMCD). We find that a one monolayer film of Mn is ferromagnetically ordered at room temperature and magnetically aligned with the fcc Co (001) substrate. The absorption spectrum of monolayer Mn is in excellent agreement with calculations for an isolated high-spin atom. By comparing our XMCD and SXA results, we conclude that the surface layer of Mn is in a high-spin state. The ferromagnetic ordering of monolayer Mn results from this high-spin layer being in direct contact with the ferromagnetic Co substrate.