1. JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany, E.U.
2. Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany, E.U.
3. Institute for Theoretical Physics, TU Wien, 1040 Vienna, Austria, E.U.
4. Helmholtz Nano Facility, Forschungszentrum Jülich, 52425 Jülich, Germany
5. AMO GmbH, Gesellschaft für Angewandte Mikro- und Optoelektronik, 52074 Aachen, Germany, E.U.
6. University of Wuppertal, 42285 Wuppertal, Germany, E.U.
7. Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
8. International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan