1. Institute of Physics, Cracow University of Technology, Podchorążych 1, 30-084 Cracow, Poland
2. Faculty of Materials Sciences and Ceramics, AGH - University of Science and Technology, al. A. Mickiewicza 30, 30-059 Cracow, Poland
3. Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Skłodowskiej 34, 41-819 Zabrze, Poland