FIG. 2: Schematic representation of structures: (a) a Cr atom in bcc Fe, (b) a Fe atom in bcc Cr, (c) Fe-Fe, (d)
Fe-Cr and (e) Cr-Cr dumbbells in bcc Fe. Fe and Cr atoms are shown as gray and blue spheres, respectively. (f)
Schematic representation of atoms in the neighbourhood of a defect (white sphere). Atoms in the rst and second
nearest neighbour shells are shown as red and green spheres, respectively.