1. Institute of Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
2. Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex, Material Systems (RCCM), Am Hubland, D-97074 Würzburg, Germany
3. Institute of Nanostructure Technologies and Analytics, Technische Physik, Universität Kassel, Kassel, Germany