1. Advances Material Engineering Div., Toyota Motor Corporation, Susono 410-1193, Japan
2. CNRS, Institut Néel, UPR 2940, 25 rue des Martyrs, BP166, 38042 Grenoble Cedex 9, France
3. Univ. Grenoble Alpes, Institut Néel, 38042 Grenoble, France
4. Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
5. Department of Physics, University of California, Davis, California 95616, USA