Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 40: Oxides and insulators
O 40.10: Vortrag
Donnerstag, 30. März 2006, 17:15–17:30, WIL A317
Thin Manganese Oxide Films on Ag(001) — •Michael Huth1, Karl-Michael Schindler1, Christian Hagendorf1, Jian Wang1, Richard Börner1, Stephan Großer1, Steffen Sachert1, Wolf Widdra1, Francesco Allegretti2, Martin Polcik2, David Sayago2, and Emily Kröger2 — 1Martin-Luther-Universität Halle-Wittenberg, FB Physik, D-06120 Halle — 2Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin
Thin films of MnO (4 ML) were grown on a Ag(001) substrate by reactive evaporation of Mn in an O2 atmosphere and investigated with XPS and NEXAFS spectroscopy at the UE56/2 BESSY beamline. The identity of the MnO film was assessed using the exchange splitting (6.2 eV) of the Mn 3s photoemission line which is highest for stoichiometric MnO. After annealing such a film to 720 K the exchange splitting is reduced to 5.6 eV pointing to a composition of MnO1−x. NEXAFS spectra of the O K-edge in normal and grazing incidence are very similar for MnO due to its cubic structure, but for MnO1−x they show a strong dependence on the angle of incidence and nearly twice as many resonances. O 1s photoelectron diffraction (PED) curves were recorded in energy scan mode for both films. The intensity modulations of the MnO film are much stronger than the ones of the MnO1−x films. We attribute this again to the lower symmetry of the MnO1−x films. Finally, the intensity ratio of the two exchange split Mn 3s photoemission lines varies for kinetic energies which indicate the presence of a local magnetic ordering above the Neel temperature.