1. Faculty of Physics and Materials Sciences Center, Philipps University, 35032 Marburg, Germany
2. Peter Grünberg Institute (PGI-3), Jülich Research Centre, 52425 Jülich, Germany
3. Fundamentals of Future Information Technology, Jülich Aachen Research Alliance (JARA), 52425 Jülich, Germany
4. Institute for Experimental Physics IV-A, RWTH Aachen University, 52074 Aachen, Germany
5. Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany