1. Lviv Polytechnic National University, 12 Bandera Str., 79013 Lviv, Ukraine
2. Kremenchuk State Polytechnical Institute, 20 Pershotravneva Str., 39614 Kremenchuk, Ukraine
3. R&D Institute for Materials SRC "Carat", 202 Stryjska Str., 79031 Lviv, Ukraine
4. Institute of Physics, RzeszowUniversity,16A2 Rejtana Str., 35‐310 Rzeszow, Poland