1. Department of Physics, Częstochowa University of Technology, Armii Krajowej 19, 42-200 Czestochowa, Poland
2. Department of Mechanics, Materials and Biomedical Engineering, Wroclaw University of Science and Technology, Smoluchowskiego 25, 50-370 Wroclaw, Poland
3. Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia