Au and Fe magnetic moments in disordered Au-Fe alloys

We report on the magnetic moments of Au and Fe in fcc and bcc disordered Au-Fe alloys determined via a combination of x-ray magnetic circular dichroic measurements at the L3,2 edges of Au and superconducting quantum interference device magnetometry. The $5d$ induced magnetic moment of Au in the fcc alloys scales with the number N of nearest Fe neighbors, from MAu=0.1 μB/atom for $N=3$ to MAu=0.2 μB/atom for $N=6$. Fe in these alloys is in a high-spin state, which carries a total magnetic moment of about 3 μB/atom. The maximum value of $5d$ induced magnetic moment of Au is 0.33 μB/atom and is exhibited when Au is placed as an impurity in a bcc Fe environment. The ratio of the orbital-to-spin $5d$ magnetic moment of Au is ML/MS≈0.2 in all samples. The experimental results are discussed with respect to first principles calculations.