1. Small Scale Systems Integration and Packaging Center, State University of New York at Binghamton, Binghamton, New York 13902, USA
2. Department of Physics, State University of New York at Binghamton, Binghamton, New York 13902, USA
3. Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259-J2-19, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
4. Laboratory for Advanced Nuclear Energy, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
5. Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
6. Institute for Materials Research, Tohoku University, Sendai, Japan
7. Center for Innovative Integrated Electronic System (CIES), Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai 980-8572, Japan
8. Center for Spintronics Research Network (CSRN), Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
9. Center for Science and Innovation in Spintronics (CSIS), Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan