1. Institute of Physics AS CR, Cukrovarnicka 10, 162 53 Prague, Czech Republic
2. Institute of Physics, Opole University, Oleska 48, 45-052 Opole, Poland
3. Research Institute of Physics and Faculty of Physics, Southern Federal University, Stachki Ave. 194, 344090, Rostov-on-Don, Russia
4. Scientific-Practical Materials Research Centre, NASB, Minsk, Belarus
5. Institute for Problems of Materials Science, National Academy of Sciences of Ukraine Krjijanovskogo 3, 03142 Kyiv, Ukraine
6. Charles University in Prague, Faculty of Mathematics and Physics, Prague 1, Czech Republic