X-ray magnetic circular dichroism for Co_<i>x</i>Fe₄₋_<i>x</i>N (<i>x</i> = 0, 3, 4) films grown by molecular beam epitaxy

Abstract

We evaluated orbital (morb) and spin magnetic moments (mspin) of CoxFe4−xN (x = 0, 3, 4) epitaxial thin films grown by molecular beam epitaxy using x-ray magnetic circular dichroism, and discussed the dependence of these values on x. Site-averaged mspin value of Fe atoms was deduced to be 1.91 μB per atom, and that of Co atoms to be 1.47 μB per atom in Co3FeN at 300 K. These values are close to 1.87 μB per Fe atom in Fe4N and 1.43 μB per Co atom in Co4N, respectively. This result implies that the Fe and Co atoms in the Co3FeN films were located both at corner and face-centered sites in the anti-perovskite lattice. Spin magnetic moments per unit cell were decreased linearly with increasing x in CoxFe4−xN. This tendency is in good agreement with theory predicted by the first-principle calculation.