1. Department of Physics, Kazimierz Wielki University in Bydgoszcz, 85090 Bydgoszcz, Poland
2. Mechantronic Department, Kazimierz Wielki University in Bydgoszcz, 85074 Bydgoszcz, Poland
3. Institute for Single Crystals, National Academy of Sciences of Ukraine, 61178 Kharkiv, Ukraine