1. Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, Slovakia
2. Faculty of Mechanical Engineering, University of Žilina, Univerzitná 1, 010 26 Žilina, Slovakia
3. Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University in Košice, Park Angelinum 9, 04154 Košice, Slovakia
4. Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, Sofia Kovalevskaya 18, 620108, Ekaterinburg, Russia