1. Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Materials, Trojanova 13, 120 00 Prague 2, Czech Republic
2. Charles University, Department of Physics of Materials, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
3. University of Chemistry and Technology Prague, Department of Metals and Corrosion Engineering, Technická 5, 166 28 Prague 6, Czech Republic
4. Institute of Physics, ASCR, v.v.i., Department of Functional Materials, Na Slovance 2, 18221 Prague 8, Czech Republic