Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)

O 35.37: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B1

Segregation of Ag due to annealing of ultrathin Fe films on Ag(001) — •Christian Otte, Daniel Bruns, Steffen Jentsch, Sören Lindemann, and and Joachim Wollschläger — Fachbereich Physik, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück

Thin Fe films are promising candidates for application in spintronic devices due to their electric and magnetic properties. In this work, ultrathin Fe films grown at room temperature on Ag(001) were post-deposition annealed in Ultra High Vacuum (UHV) at 250^∘C. This was monitored via X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The surface structure and morphology was studied before and after annealing in UHV by Scanning Tunneling Microscopy (STM) and Spot Profile Analysis Low Energy Electron Diffraction (SPA-LEED). The as-deposited Fe forms column shaped islands. Annealing in UHV at 250^∘C leads to a strong change in surface structure and morphology accompanied by surface segregation of Ag. While SPA-LEED shows an additional (√2×√2)R45^∘ superstructure after annealing, STM reveals large, flat Ag(001) terraces without any superstructures on them. Strongly three dimensional structures are likely to contain part of the deposited Fe. Nevertheless the XPS results suggest that most of the Fe has to be buried underneath the segregated Ag. This assumption is supported by energetic considerations comparing surface free energies of Fe(001) and Ag(001).