1. Faculty of Chemistry, Department of Rare Earths, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznan, Poland
2. Faculty of Physics, Institute of Experimental Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
3. Department of Man-Made Fibers, Technical University of Lodz, Żeromskiego 116, 90-924 Lodz, Poland