Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)
O 27.47: Poster
Dienstag, 24. März 2009, 18:30–21:00, P2
Structure and morphology of epitaxial manganese oxide films on Ag(001) — •Klaus Meinel, Michael Huth, Sebastian Polzin, Konrad Gillmeister, and Wolf Widdra — Martin-Luther-Universität Halle-Wittenberg, Germany
STM, SPALEED, AES and HREELS have been applied to study the formation and thermal stability of manganese oxide films on Ag(001). The films have been grown by reactive Mn deposition in an O2 atmosphere. Whereas films deposited at room temperature show a layer-like growth mode, deposition at slightly higher temperatures yields an embedding of film islands in the substrate due to Ag surface diffusion. Film deposition in an O2 atmosphere of 2x10-8 mbar and postannealing to 620 K results in a MnO(001)-(1x1) rock salt structure which may display a moiré-like relaxation pattern in SPALEED. For film deposition in 8x10-8 mbar O2 and postannealing, a MnO(001)-(2x1) row structure is observed with STM and SPALEED. At a film thickness around 5 ML a new structure develops which is indicated by a brilliant (2x2) diffraction pattern. It is assigned to the formation of a spinel-like Hausmannite Mn3O4(001) film structure where the lattice vectors are aligned along the [110]-like directions of the Ag(001) substrate. This specific orientation implies an almost vanishing misfit which may explain the high structural perfection of the Mn3O4 films. These results will be compared with recent data for manganese oxide thin films on Pd(001) and Pt(111) [1,2].
[1] Bayer et al., Phys. Rev. B 76, 165428 (2007).
[2] Hagendorf et al., Phys. Rev. B 77, 075406 (2008).