1. Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute for Physics, Augsburg University, D-86135 Augsburg, Germany
2. General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
3. Hochfeld-Magnetlabor Dresden (HLD), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany
4. Institute de Physique de la Matière Complexe, EPFL, CH-1015 Lausanne, Switzerland