Magnetic Proximity Effect in Graphene/BiFeO₃ Hybrid System

Graphene, a very intriguing 2D massless fermionic system with high carrier mobility, is promising for spintronics. However, the spin splitting is always weak in pristine graphene. Here, we report the transport properties of graphene coupled to an antiferromagnetic insulator BiFeO₃. It is found that the magnetic proximity effect results in a strong Zeeman splitting in graphene with the obvious spin splitting in Landau levels. ν=0 quantum Hall state of the coupled system undergoes quantum phase transitions as a result of the combined effect of exchange field and external field. The direction of the external magnetic field also shows its capability to adjust the proximity effect at the interface, by tuning the interfacial magnetization. We also achieve the electrical control of the magnetic proximity effect via strong magneto-electric coupling in BiFeO₃ nanoplates. Our findings in graphene/BiFeO₃ heterostructure are therefore promising for future spintronics.