1. B. I. Verkin Institute of Low-temperature Physics and Engineering, National Academy of Sciences of Ukraine, pr. Nauki 47, Kharkov 61103, Ukraine
2. B. I. Verkin Institute of Low-temperature Physics and Engineering, National Academy of Sciences of Ukraine, pr. Nauki 47, Kharkov 61103, Ukraine and V. N. Karazin Kharkov National University, pl. Svobody 4, Kharkov 61077, Ukraine