A 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-principles full-potential local-orbital calculations. Co growth has been shown to display different paths according to various conditions. The Co/Fe(001) interface shows a distorted cubic Co growth (known as bct) up to about 15 monolayers (ML) turning to the equilibrium hcp Co structure for larger thickness. Co growth onto the surface oxidized $\mathrm{Fe}\left(001\right)\mathrm{}-p(1\mathrm{}\times 1)\mathrm{O}$ shows a similar behavior with an extended stability range of the bct structure up to about 35 ML. Spin-dependent effects are, moreover, enhanced due to an oxygen surfactant action. FeCo(001) formation is shown to take place by thermal treatment of the interface. Its features are interpreted in terms of band filling arguments, and the surface oxidation displays again a considerable enhancement of spin-dependent effects in analogy with the surface oxidation of pure Fe(001).

• Received 15 December 1999

DOI:https://doi.org/10.1103/PhysRevB.61.15294