[1] Tver State Univ, Lab Magnetoelect, Tver 170000, Russia
[2] Res Inst mat Sci & Technol, Zelenograd RS-124460, Russia
[3] LEG ENSIEG, Lab Electrotechnique Grenoble, F-38402 St Martin Dheres, France
[4] CNRS, inst Neel, UJF, F-38042 Grenoble, France