1. Friedrich-Schiller-University Jena, Institute of Solid State Physics, Helmholtzweg 5; 07743 Jena Germany
2. IFW Dresden, Institute for Metallic Materials, Helmholtzstrasse 20; 01169 Dresden Germany
3. Karlsruhe Institute of Technology, Institute of Solid State Physics, Hermann-von-Helmholtz-Platz 1; 76344 Eggenstein-Leopoldshafen Germany