Graphene on Chromia: A System for Beyond-Room-Temperature Spintronics

Evidence of robust spin-dependent transport in monolayer graphene, deposited on the (0001) surface of the antiferromagnetic (AFM)/magneto-electric oxide chromia (Cr₂O₃), is provided. Measurements performed in the non-local spin-Hall geometry reveal a robust signal that is present at zero external magnetic field and which is significantly larger than any possible ohmic contribution. The spin-related signal persists well beyond the Néel temperature (≈307 K) that defines the transition between the AFM and paramagnetic states, remaining visible at the highest studied temperature of close to 450 K. This robust character is consistent with prior theoretical studies of the graphene/Cr₂O₃ system, predicting that the lifting of sub-lattice symmetry in the graphene shall induce an effective spin–orbit term of ≈40 meV. Overall, the results indicate that graphene-on-chromia heterostructures are a highly promising framework for the implementation of spintronic devices, capable of operation well beyond room temperature.