Room-temperature ferromagnetism in Co-doped 2D graphitic ZnO*

Long-range ferromagnetic ordering has been successfully observed in 2D materials, displaying novel quantum phases and spintronic phenomena. Although it is a giant step forward in fundamental physics to realize 2D ferromagnetism, most 2D magnets still suffer from multiple challenges including Curie temperatures below room temperature, chemical instability, and so on, which significantly limit their emergent applications in computing and storage. Recently, we successfully observed 2D ferromagnetism above room temperature, by introducing Co atoms into a non-magnetic 2D vdW system, graphitic ZnO. Room-temperature ferromagnetism has been verified in 2D Zn_1-xCo_xO (ZCO) by means of superconducting quantum interference device, magneto-optic Kerr effect, and X-ray magnetic circular dichroism measurements. ZCO also shows exceptional stability in ambient conditions as well as at elevated temperatures. Our work indicates that the one-atom-thick ZCO can serve as a promising platform to explore new magnetic and topological phases with above-room-temperature T_C, environmental stability, and dopant-tunability.