1. B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Nauky Ave., Kharkiv 61103, Ukraine
2. NSC Kharkov Institute of Physics and Technology, 1 Akademicheskaya St., Kharkiv 61108, Ukraine
3. Vasyl Stefanyk Precarpathian National University, 57 Shevchenko St., Ivano-Frankivsk 76018, Ukraine