Surfactant effect and dissolution of ultrathin Fe films on Ag(001)

The effects of annealing on the structure of ultra thin Fe films (4-10 ML) deposited at 150 K on Ag(001) were studied by synchrotron radiation photoelectron diffraction (PED) and x-ray diffraction (XRD). The occurrence of a surfactant-like stage, in which a single layer of Ag covers the Fe film is demonstrated for films of 4-6 ML heated at 500-550 K. Evidence of a stage characterized by the formation of two Ag capping layers is also reported. As the annealing temperature was increased beyond 700 K the surface layers closely resembled the structure of bare Ag(001) with the residual presence of subsurface Fe aggregates. The data illustrate a film dissolution path which is in agreement with recent theoretical models [J. Roussel Phys. Rev. B 60, 13890 (1999)]