1. Berdyansk State Pedagogical University,The Department of Physics and Methods of Teaching Physics,Berdyansk,Ukraine
2. L.N. Gumilyov Eurasian National University 2 Satpayev Str.,Nur-Sultan,Kazakhstan,010008
3. Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46,Warsaw,Poland,02-668
4. Institute of Solid State Physics University of Latvia 8 Kengaraga str.,Riga,Latvia,LV-1063