1. Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
2. Department of Physics and Astronomy, University of Mt. Union, 1972 Clark Ave, Alliance, OH, 44601, USA
3. Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands