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DS: Fachverband Dünne Schichten

DS 11: Thin Film Characterisation: Structure Analyse and Composition (XRD, TEM, XPS, SIMS, RBS, ...)

DS 11.6: Vortrag

Dienstag, 26. Februar 2008, 10:45–11:00, H 2013

X-ray Photoelectron diffraction study of thin epitaxial MnO films — •Christian Langheinrich¹, Mathias Nagel², Angelika Chassé¹, and Thomas Chassé² — ¹Martin-Luther-Universität Halle-Wittenberg, FB Physik, FG Theoretische Physik, 06099 Halle — ²Eberhard-Karls-Universität Tübingen, Institut für Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, 72076 Tübingen

Transition metal oxides reveal interesting properties due to their high electronic correlation and magnetic phenomena. The MnO/Ag(001) system is an interesting model system due to the high lattice mismatch (9*%). By choosing the optimal preparation method either pseudomorphic or relaxed growth of ultrathin MnO on Ag(001) can be obtained. Recently, evidence for a tetragonal distortion of initial MnO layers epitaxially grown on Ag has been provided from both XPD and XAS experiments but further understanding seems necessary [1, 2].

Here, XPD has been applied to investigate MnO(001) and Ag(001) bulk, as well as ultrathin epitaxial MnO films on Ag(001). Calculations have been performed within a multiple scattering cluster model in order to obtain the lattice parameters. An r-factor analysis indicates that the MnO films exhibits a tetragonal distortion and relaxes step by step to bulk MnO with thicker films. In addition we are able to show the relaxation in dependence on the film thickness.

[1] M. Nagel, I. Biswas, P. Nagel, E. Pellegrin, S. Schuppler, H. Peisert, T. Chassé, Phys. Rev. B 75 (2007) 195426

[2] A. Chassé, Ch. Langheinrich, F. Müller, S. Hüfner, Surf. Sci. (accepted)