Stability and magnetism of ultrathin Cr films on a Fe(001) substrate

Itinerant magnetism of ultrathin epitaxial Cr overlayers on a Fe(001) substrate and their energy stability with respect to Cr-Fe interdiffusion were studied by means of ab initio electronic structure calculations. The latter were based on the tight-binding linear muffin-tin orbital method and the coherent potential approximation. The interdiffusion was simulated by two-dimensional substitutionally disordered Cr-Fe alloys formed within two layers at the Cr/Fe interface. For a 1 monolayer Cr film a tendency to surface alloy formation is found in contrast to a 2 monolayer Cr film which seems to be stable with respect to Fe-Cr intermixing. A comparison of the calculated results to recent experimental data is presented and an interplay between the energy stability and magnetism of the films is pointed out. Presented at the VIII-th Symposium on Surface Physics, Třešt’ Castle, Czech Republic, June 28 – July 2, 1999.