1. Institute
of Metal Physics, Russian Academy of Sciences—Ural Branch, S. Kovalevskaya
str., 18, 620990 Yekaterinburg, Russia
2. Fachbereich
Physik, Universität Osnabrück, Barbarastrasse 7, D-49069 Osnabrück, Germany
3. St. Petersburg State University, 7-9, Universitetskaya nab., St. Petersburg 199034, Russia