1. Regional
Centre of Advanced Technologies and Materials, Departments of Physical
Chemistry and Experimental Physics, Faculty of Science, Palacký University in Olomouc, 17. listopadu 1192/12, CZ-77146 Olomouc, Czech Republic
2. Department
of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina, Greece
3. Physics
Department, University of Ioannina, GR-45110 Ioannina, Greece