Ferromagnetic iron-chromium alloys

The spin polarized discrete variational method in the local density approximation is used to calculate the electronic structure of 15-atom clusters representing Fe-Cr alloys. The Fe local moment at the central site is found to depend on the orientation (relative to that of Fe) of the Cr moment in the neighbouring shell. For parallel orientation, the Fe moment decreases with increasing number of Cr atoms while it increases slightly in the antiparallel case. The Cr moment dependence on Cr in the NN shell is also determined. These results are incorporated in an approximate relation leading to computation of average moments, and comparison to experimental data is made. It is concluded that there is ferromagnetic coupling between Fe and Cr in the Cr-rich region.