1. Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská Dolina F2, 842 48 Bratislava, Slovakia
2. Detached Workplace of Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Sadová, 1148 Turany, Slovakia
3. Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovakia
4. Institute of Materials and Machine Mechanics SAS, Dúbravská cesta 9, 845 11 Bratislava, Slovakia