1. Beijing National Laboratory of Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences Beijing 100190 China
2. School of Physical SciencesUniversity of Chinese Academy of Sciences Beijing 100049 China
3. NanoSpin, Department of Applied PhysicsAalto University School of Science P. O. Box 15100, FI‐00076 Aalto Finland
4. Peter Grünberg Institut and Institute for Advanced SimulationForschungszentrum Jülich and JARA Jülich 52425 Germany
5. Institut de Ciència de Materials de Barcelona (ICMAB), CSIC Bellaterra 08193 Catalunya Spain