1. Department of Physics, Graduate School of Science, Osaka University, 1-1 Machikaneyamacho, Osaka 560-0043, Japan
2. Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan
3. Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Osaka 560-8531, Japan
4. Institute for Physics of Intelligence and Department of Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
5. JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan