1. Institute of Physics; Pedagogical University of Cracow; ul. Podchorążych 2 30-084 Kraków Poland
2. Academic Center for Materials and Nanotechnology; AGH University of Science and Technology; Av. A. Mickiewicza 30 30-059 Kraków Poland
3. Institute of Applied Physics; Military University of Technology; ul. Kaliskiego 2 00-908 Warsaw Poland