[1] Univ Grenoble Alpes, Grenoble, France
[2] Inac Sp2m, CEA, Nanophys & Semicond Grp, Grenoble, France
[3] Inst Neel, CNRS, Grenoble, France
[4] Inac, CEA, Minatec Campus, Grenoble, France
[5] Univ Valencia, Inst Mat Sci, E-46003 Valencia, Spain
[6] Inst Univ France, Paris, France