Growth and structure of thin MnO films on Ag(001) in dependence on film thickness

We have investigated the structure of thin MnO films grown on a single-crystal Ag(0 0 1) surface in dependence on layer thickness by combination of low energy electron diffraction (LEED) and X-ray photoelectron diffraction (XPD) methods. The analysis of LEED profiles shows that the in-plane lattice constant of the epitaxial grown MnO film on Ag(0 0 1) depends strongly on the thickness of the film. The analysis of LEED data leads to the assumption that the lattice mismatch between MnO and Ag may be released by a tetragonal distortion of the film in comparison to bulk-MnO. In addition, XPD measurements in forward-scattering conditions are considered. Polar-angle scans have been recorded and analysed for Mn2p and O1s photoelectrons excited by Al Kα radiation to get detailed structural parameters. It is shown that, in contrast to thin films of simple metals, the forward-scattering model should be applied very carefully in the interpretation of XPD data.