1. Contribution from the Université Bordeaux 1, CNRS, Centre de Recherche Paul Pascal - UPR8641, 115 avenue du Dr. Albert Schweitzer, 33600 Pessac, France, CNRS, Institut Néel, BP 166, 25 av. des Martyrs, 38042 Grenoble, France, Laboratorium für Festkörperphysik, Wolfgang-Pauli-Strasse 16 ETH Hönggerberg, CH-8093, Zürich Switzerland. Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan, and CREST, Japan Science and Technology...