1. B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Nauki Ave., Kharkov 61103, Ukraine
2. Institute of Physics, Polish Academy of Sciences, Warsaw 02-668, Poland
3. National Scientific Center Kharkov Institute of Physics and Technology, 1 Akademicheskaya St., Kharkov 61108, Ukraine
4. M. V. Lomonosov Moscow State University, Moscow 119991, Russia