1. Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
2. Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan.
3. National Institute for Materials Science (NIMS), Tsukuba 304-0047, Japan.
4. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian, China.
5. Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany.
6. Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany.
7. WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
8. Center for Science and Innovation in Spintronics, Core Research Cluster, Tohoku University, Sendai 980-8577, Japan.