Institution: | a State Key Laboratory for Magnetism, Institute of Physics, CAS, P.O. Box 603, Beijing 100080, People's Republic of China b Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, Valckenierstraat 65, 1018XE Amsterdam, The Netherlands c Center of Magnetic Materials and Magnetic Technology, Hebei University of Technology, Tianjing 300130, People's Republic of China |