Electronic and magnetic properties of the Co/Fe(001) interface and the role of oxygen

combined theoretical and experimental study of the structural, electronic, and magnetic properties of a Co thin film growth onto Fe(001) substrate is reported. This includes also an analysis of the role of oxygen in modifying the properties of the Co/Fe interaction. Experimental results obtained by spin-resolved absorbed current and inverse photoemission spectroscopies, as probes of the empty electron states, show nice agreement with first-princi ples full-potential local-orbital calculations. Co growth has been shown to display different paths according to various conditions. The Co/Fe(001) in terface shows a distorted cubic Co growth (known as bet) up to about 15 mon olayers (ML) turning to the equilibrium hep Co structure for larger thickne ss. Co growth onto the surface oxidized Fe(001)-p(1 X 1)O shows a similar b ehavior with an extended stability range of the bet structure up to about 3 5 ha. Spin-dependent effects are, moreover, enhanced due to an oxygen surfa ctant action. FeCo(001) formation is shown to take place by thermal treatme nt of the interface. Its features are interpreted in terms of band filling arguments, and the surface oxidation displays again a considerable enhancem ent of spin-dependent effects in analogy with the surface oxidation of pure Fe(001).