1 Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, 48149, Münster, Germany.
2 Institute of Solid State Theory, University of Münster, Wilhelm-Klemm-Strasse 10, 48149, Münster, Germany.
3 Center for Atomic-Scale Materials Design (CAMD), Department of Physics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
4 Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 rue des Martyrs, 38042, Grenoble, France.
5 Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, 48149, Münster, Germany. Rudolf.Bratschitsch@uni-muenster.de.