1. Platov South-Russian State Polytechnic University (NPI), Prosveschenya 132, 346428 Novocherkassk, Russian Federation
2. State Scientific Institution “Institute for Single Crystals” of National Academy of Sciences of Ukraine, Lenin Ave. 60, 61001 Kharkiv, Ukraine
3. V. N. Karazin Kharkiv National University, 4 Svobody sq., Kharkiv 61202, Ukraine