FIG. 3: Schematic representation of the process of
formation of a mixed Fe-Cr dumbbell (a) by adding a
Cr atom to a Fe site and (b) by adding a Fe atom to a
Cr site. Schematic representation of formation of a
vacancy (c) on a Fe site and (d) on a Cr site. Fe and Cr
atoms are shown as gray and blue spheres, respectively.