1. National Institute for Materials Science, Tsukuba 305-0047, Japan
2. National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Japan
3. ICQD, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
4. Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan
5. PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan
6. Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
7. Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan