1. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
2. Adroit Materials, Inc., 2054 Kildaire Farm Rd., Cary, North Carolina 27518, USA
3. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919, USA
4. Division of Applied Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan