1. Institut für Physik, Johannes Gutenberg Universität-Mainz, 55099, Mainz, Germany
2. Graduate School of Excellence Materials Science in Mainz (MAINZ), Staudinger Weg 9, 55128, Mainz, Germany
3. Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
4. Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
5. Institute for Theoretical Physics, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
6. Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
7. Institute of Physics ASCR, Cukrovarnicka 10, 162 53 Praha 6, Czech Republic
8. Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands