1. Institute
of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
2. Department
of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
3. Institute
of Solid State Physics, Friedrich Schiller University Jena, Helmholtzweg
5, 07743 Jena, Germany
4. Peter
Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
5. Jülich Aachen Research Alliance (JARA)−Fundamentals of Future Information Technology, 52425 Jülich, Germany
6. Department
of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
7. Graduate School of Excellence Materials Science in Mainz, Erwin-Schrödinger-Straβe 46, 67663 Kaiserslautern, Germany
8. Dipartimento
di Fisica, Università degli Studi di Milano, Via Celoria
16, 20133 Milano, Italy