[1] Univ Strasbourg, CNRS, Inst Phys & Chim Mat Strasbourg, F-67034 Strasbourg 2, France
[2] Univ Strasbourg, CNRS, NIE UMR 7504, F-67034 Strasbourg 2, France
[3] Nancy Univ, Inst Jean Barriol, UMR CNRS 7036, Lab Cristallog Resonance Magnet & Modelisat,CRM2, F-54506 Vandoeuvre Les Nancy, France
[4] ESRF, F-38043 Grenoble, France
[5] Karlsruhe Inst Technol, Inst Phys, D-76131 Karlsruhe, Germany
[6] Karlsruhe Inst Technol, Ctr Funct Nanostruct, D-76131 Karlsruhe, Germany