1. Institute of Experimental Physics, Faculty of Mathematics, Physics and Informatics, University of Gdansk, ul. Wita Stwosza 57, 80-952 Gdańsk, Poland
2. Institute of Materials Technology Faculty of Materials Engineering, Silesian University of Technology, ul. Akademicka 2A, 44-100 Gliwice, Poland
3. Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland