1. Institute of Inorganic Chemistry and Metallurgy of Rare Elements, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50−370 Wrocław, Poland, Fax: (internat.) +48‐(0)71‐3284330
2. Faculty of Chemistry, University of Wrocław, Joliot‐Curie 14, 50−383 Wrocław, Poland
3. International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 53−529 Wrocław, Poland