Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 45: Metal Substrates II
O 45.6: Vortrag
Mittwoch, 13. März 2013, 11:45–12:00, H42
Surface structure of ultrathin Fe films on Ag(001) post-deposition annealed in O2 atmosphere — •Daniel Bruns, Steffen Jentsch, Sören Lindemann, and Joachim Wollschläger — Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück
Iron oxides are used in different applications as spintronics or heterogeneous catalysis. In this work, ultrathin Fe films grown at room temperature on Ag(001) were post-deposition annealed in 10−5 mbar O2 atmosphere at 300∘C for 50 minutes. Since the surface has a strong influence on the properties of ultrathin films, the surface structure was investigated by Low Energy Electron Diffraction (LEED) and Scanning Tunneling Microscopy (STM). Submonolayer Fe films wet the Ag(001) substrate due to annealing in oxygen forming at least partial FeO, as concluded from LEED. Straight trenches aligned either in Ag[110] or Ag[110] direction separate different FeO domains. On the other hand, with increasing Fe coverage the films show a three dimensional behavior upon annealing forming several exposed layers. In this case, LEED suggests two hexagonal structures as well as two low ordered rectangular structures rotated by 90∘ against each other, respectively. These structures were found to be located on different exposed layers at the surface via STM. The topmost layer of the oxidized films revealed a poorly ordered (2×3) superstructure, while the hexagonal surface structure was only found on deeper exposed layers. We created models to describe the observed surface structures suggesting partial formation of FeO as well as Fe3O4−δ at the surface.