thin films*

Cr₂O₃ is an interesting insulating antiferromagnetic material, which has been widely investigated recently, including in the studies of the spin Seebeck effect and the long spacing distance spin transport. Cr₂O₃ is also a well-known magneto-electric material, whose sublattice spins can be switched by an electric field. In this study, we first grow a 5 nm thick Pt layer on the substrate of (0001)-oriented Al₂O₃ using magnetron sputtering, and then the Cr₂O₃ thin films using high vacuum pulsed laser deposition. 1 nm Co is grown on top of Cr₂O₃ by molecular beam epitaxy or magnetron sputtering, followed by a 2 nm thick Pt capping layer deposited in-situ to prevent the oxidation of the ferromagnetic Co. The Co layer shows a very strong perpendicular magnetic anisotropy with exchange bias by anisotropy magnetoresistance measurements. The exchange bias can be reversibly manipulated by the gating electric field in Cr₂O₃ between the bottom and top Pt layers. The magneto-electric manipulation of Cr₂O₃ spins offers potential to switch the magnetization in high-density memory devices incorporating antiferromagnets with low energy consumption.