Study of the growth and the magnetism of ultrathin films of Cr on Fe

The surface magnetic properties of ultrathin Cr films grown on an O/Fe/Ag(100) substrate have been studied by means of spin polarized metastable de-excitation spectroscopy. The presence of oxygen on top of the Fe film inhibits the segregation of Ag and strongly reduces Fe/Cr intermixing. The magnetization of the outermost Cr layer is zero immediately after its deposition, whereas, upon annealing up to 500 K, a net magnetization is observed which reverse its direction as a function of the film thickness already from a 3 ML thick film. The magnetization reversal is in agreement with the layered antiferromagnetic structure of Cr clearly observed for thicker films.