[1] Univ Paris 06, CNRS, UMR 7588, Phys Solides Grp, F-75015 Paris, France
[2] Univ Paris 07, CNRS, UMR 7588, Phys Solides Grp, F-75015 Paris, France
[3] ENSAM, LM3, CNRS, UMR 8006, F-75013 Paris, France
[4] Univ Metz, LSMCL, F-57078 Metz, France
[5] ENSCP, LCAES, CNRS, UMR 7544, F-75321 Paris, France
[6] Univ Autonoma Madrid, Dept Fis Aplicada C12, E-28049 Madrid, Spain