1. Physikalisches Institut der Universität Würzburg, 97074 Würzburg, Germany
2. A.F. Ioffe Physico‐Technical Institute, RAS, 194021 St. Petersburg, Russia
3. Experimentelle Physik 2, Universität Dortmund, 44221 Dortmund, Germany
4. National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545, USA
5. High Magnetic Field Laboratory, University of Nijmegen, 6525 Nijmegen, The Netherlands
6. Institute of Physics, Polish Academy of Sciences, 02668 Warsaw, Poland