1. Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
2. CEMS, RIKEN, Saitama 351-0198, Japan.
3. Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan.
4. Laboratory of Nanoscale Magnetic Materials and Magnonics(LMGN), Institute of Materials (IMX), School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
5. Research and Development Group, Hitachi Ltd., 1-280 Higashi-koigakubo, Kokubunji-shi, Tokyo 185-8601, Japan.
6. Institute of Microengineering (IMT), School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
7. Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China.
8. CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.