Electronic and magnetic properties of ultrathin Fe-Co alloy nanowires

We have investigated the electronic structures and magnetic properties of free-standing Fe-Co nanowires by density functional theory (DFT) calculations using ultrasoft pseudopotential plane wave method. We have considered the free-standing Fe(1-x)Cox nanowires with centered-staggered triangle and square structures. The optimized lattice constants obtained by total energy calculation are slightly longer than those of the experimental results and the variation of magnetic moments with Co concentration is similar to the Slater-Pauling curve. The spin-polarized density of states (DOS) of Fe0.8Co0.2 nanowire reveals a nearly half-metallic character. We have found the coercivity estimated by the chain-of-spheres model is consistent with the experimental results for Fe-Co nanowire arrays fabricated in porous templates.