First-principles atomistic study of surfaces of Fe-rich Fe-Cr

The surface properties of Fe-rich ferromagnetic Fe-Cr alloys are investigated using a first-principles quantum-mechanical method. In dilute alloys, the surfaces are dominated by Fe, whereas the Cr-containing surfaces become favorable when the bulk Cr concentration exceeds the limit of ∼ 10 atomic per cent. The abrupt change in the surface behavior is the consequence of complex competing magneto-chemical interactions between the alloying atoms. Considering the quantities of various features: equilibrium surface profiles, chemical potentials, segregation energies, surface energies, magnetic moments, mixing energies and pair interactions, within a wider range of bulk and surface concentrations enables us to build a comprehensive picture of the physics of Fe-Cr surfaces. Using the present achievements many previously controversial results can now be merged into a consistent model of Fe-rich Fe-Cr alloys.