1. Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425 Juelich, Germany
2. Institute for Electronic Materials, IWE2, RWTH Aachen University, 52074 Aachen, Germany
3. Elettra - Sincrotrone
Trieste S.C.p.A., S.S. 14 km - 163,5 in AREA Science Park, I-34149 Basovizza, Trieste, Italy