1. Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany
2. M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 18 S. Kovalevskaya Str., Yekaterinburg 620137, Russia
3. Institute of Inorganic Chemistry, University of Cologne, Greinstrasse 6, 50939 Cologne, Germany