1. IT4Innovations Center and Nanotechnology Center, VSB - Technical University of Ostrava, 17. listopadu 15, CZ 708 33 Ostrava-Poruba, Czech Republic
2. Institute of Technology, Pedagogical University, ul. Podchorazych 2, 30-084 Cracow, Poland
3. Centre of Low Temperature Physics of Slovak Academy of Sciences and Institute of Physics, P. J. Š afárik University, Park Angelinum 9, 040 00 Koš ice, Slovakia