1. Peter Grünberg Institut (PGI-7) Forschungszentrum Jülich GmbH,Jülich,Germany
2. Institute for Solid State Physics Friedrich Schiller University Jena,Jena,Germany
3. Institute of Electronic Materials II RWTH Aachen University,Aachen,Germany
4. Institute for Solid State Physics Friedrich Schiller University Jena,Department of Quantum Detection Leibniz Institute of Photonic Technology,Jena,Germany