1. Department of Electric Engineering, Graduate School of Engineering, Gunma University, Japan
2. Institute of Material Structure Science, KEK, Japan
3. Cross-Correlated Materials Research Group, RIKEN, Japan
4. Department of Applied Physics, Graduate School of Engineering, University of Tokyo, Japan
5. Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Japan
6. Department of Physics, Graduate School of Science, Osaka University, Japan