1. B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkov 61103, Ukraine
2. W. Trzebiatowski Institute for Low Temperatures and Structure Research PAS, Wroclaw 50-422, Poland
3. Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142190, Russia
4. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Moscow 119991, Russia