1. Donetsk Institute for Physics and Engineering Named after O.O. Galkin, NAS of Ukraine, 72 R. Luxembourg Str., 83114 Donetsk, Ukraine
2. V. Bakul Institute for Superhard Materials NAS of Ukraine, 2 Avtozavods’ka Str., 04074 Kyiv, Ukraine
3. G.V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03680 Kyiv-142, Ukraine