1. Institute of Materials Science, Kaunas University of Technology, K. Baršausko St. 59, Kaunas LT-51423, Lithuania
2. Department of Physics, Kaunas University of Technology, Studentų St. 50, Kaunas LT-51368, Lithuania
3. International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
4. Institute of Chemical Physics, University of Latvia, 19 Raina Blvd., Riga LV-1586, Latvia