1. Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovak Republic
2. , Faculty of Electrical Engineering and Information Technology, Institute of Nuclear and Physical Engineering, Department of Physics, Slovak University of Technology in Bratislava, 812 19 Bratislava, Slovak Republic
3. Centre of Excellence for Advanced Materials Application SAS, CEMEA, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovak Republic