Electronic structure, magnetic properties, Mössbauer isomer shifts, and hyperfine fields of disordered Fe-rich Fe-Al alloys

The embedded-cluster model within the framework of the discrete variational method is used to carry out self-consistent-field electronic structure calculations for the isomer shifts, the hyperfine magnetic fields, and magnetic moments on several distinct iron sites in a disordered Fe-rich Fe-Al alloy. We analyze the dependence of those quantities on the number of nearest and next-nearest Al neighbors, on the symmetry of the local environments, and on lattice-parameter variation. Our results for the variations of the hyperfine field due to the presence of aluminum neighbors are in good agreement with experiment. The results for magnetic moments indicate that the antiferromagnetic coupling between localized and conduction electrons decreases as the Al content in the alloy increases.