1. Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Spintronics Research Group (PROSPIN); P.O. Box 91 H-1521 Budapest Hungary
2. Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), D-91054 Erlangen, Germany and Joint Institute of Advanced Materials and Processes (ZMP); D-90762 Fürth Germany
3. Yachay Tech. University, School of Physical Sciences and Nanotechnology, 100119 Urcuquí, Ecuador and Institut für Experimental Physik, Freie Universität Berlin; Arnimallee 14 D-14195 Berlin Germany