1. Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
2. Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA, and Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
3. Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
4. Center for Spintronics Integrated Systems, Tohoku University, Sendai 980-8577, Japan
5. Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai 980-0845, Japan
6. Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
7. Center for Science and Innovation in Spintronics (Core Research Cluster), Tohoku University, Sendai 980-8577, Japan
8. Physics Department and Center for Advanced Nanoscience, University of California San Diego, La Jolla, Ca. 92093, USA