Origin of the Co uniaxial volume anisotropy of the fcc Co/Ni/Cu(001) system

We studied layer selectively the magnetic moments on a: Cu/9 Angstrom Co/50 Angstrom Ni/Cu/Si(001) and a Cu/50 Angstrom Ni/Cu/Si(001) structure using polarized neutron reflection. The magnetic moments for the Cu/Co/Ni/Cu structure are 1.70+/-0.20 mu(B) and 0.57+/-0.05 mu(B) for the Co and Ni, respectively, and within error the same as the relevant bulk magnetic moments at room temperature. For the Cu/Ni/Cu sample the magnetic moment per Ni atom of 0.53+/-0.03 mu(B) is only slightly lower than the bulk value. Within error the same magnetic moments are determined for a Cu/22 Angstrom Co/11 Angstrom Cu/53 Angstrom Ni/Cu/Si(001) structure supporting the results on the Cu/Co/Ni/Cu(001) and Cu/Ni/Cu(001) structures. Using the magnetic-moments values determined by polarized neutron reflection, we conclude that the uniaxial Co volume anisotropy for the Cu/Co/60 Angstrom Ni/Cu(001) structures can be attributed to the Co shape anisotropy alone. [S0163-1829(99)03725-X].