1. II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
2. European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France.
3. Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy.
4. Dipartimento di Fisica, Università di Trento, via Sommarive 14, 38123 Povo (TN), Italy.
5. Abteilung Kristallographie, Institut für Geologie und Mineralogie, Zülpicher Strasse 49b, D-50674 Köln, Germany.
6. Institut für Theoretische Physik, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
7. Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden.
8. Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden.
9. Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden.
10. M.N. Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, 620137 Ekaterinburg, Russia.
11. Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia.
12. Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.