Magnetism in strained pseudomorphic ultrathin films of fcc 3d-transition metals (Cr, Mn, Fe, Co and Ni) with lateral lattice parameters of bulk fcc-Cu(001)

Pseudomorphic ultrathin (1–4 ML) free standing films, overlayers, and sandwiches of Cr, Mn, Fe, Co and Ni on fcc-Cu(001) are investigated using spin-polarized ab-initio   calculations. All free standing thin films have quite high magnetic moment, with the exception of the 2 ML Mn film which has zero magnetic moment. Sandwiches show the same magnetic behavior as overlayers, but with reduced magnetic moments. The 3 ML overlayer of Fe has a different structure than any other overlayer structure. Sandwiches built of monolayers of Ni and Cr in Cu have zero magnetic moment. The ultrathin free standing films, overlayers and sandwiches of Cr, Mn and Fe exhibit an oscillating magnetic moment depending upon the number of layers. We attribute this to alternating ferromagnetic and antiferromagnetic coupling. On the contrary, thin films of Co and Ni always show a ferromagnetic coupling, with a magnetic moment per atom converging towards a constant value. The magnetic moment induced in Cu atoms at the interface is significant for Mn, Fe, and Co (0.02–0.07μB), while it is zero for the Ni/Cu interface.