Structure and magnetism of self-assembled Fe nanowires on a faceted Cu(332) surface : the influence of oxygen-induced reconstruction

We present a study on the structural and magnetic properties of Fe nanowires as grown on an oxidized-reconstructed Cu(332) surface. A template surface consisting of alternate parallel stripes of Cu(111) terraces and (110) oxidized facets, with a periodicity of 4 nm, was used to grow iron wires, by the selective affinity of iron to the oxygen adsorption sites. Atomic resolution scanning tunnelling microscopy shows that Fe grows preferentially on the (110) facets, forming well-ordered Fe nanowires in the submonolayer regime. The (111) terraces are not affected by the iron deposition. Magneto-optical Kerr effect and x-ray magnetic circular dichroism reveal a long-range magnetic ordering of the wires with an out-of-plane magnetic easy axis at an early stage of the Fe growth. For coverages higher than 2-3 atomic layers, the magnetization switches to in-plane, but is perpendicular to the stripes.