1. Regional
Centre for Advanced Technologies and Materials, Department of Physical
Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
2. Department
of Materials Science, University of Patras, Patras 265 04, Greece
3. Physics
Department, University of Ioannina, Ioannina 455 00, Greece