Nonlocal spin transport in antiferromagnet Cr₂O₃ thin film

Cr₂O₃ is an interesting insulating antiferromagnetic material, which has been widely investigated recently, including in the electric field control of the exchange bias and spin Seebeck effect. In our study, high quality Cr₂O₃ films are epitaxially grown on the substrates of (0001) Al₂O₃ using high vacuum pulsed laser deposition. The layer by layer growth is monitored by the in-situ reflection high energy electron reflection oscillations, and atomic force microscope result shows the surface is atomically flat. The spin transport on the thin films is probed by using the nonlocal spin transport geometry with two parallel electrodes via the standard low frequency lock-in technique. Temperature and magnetic field dependences of the nonlocal spin signal are systematically studied. Interestingly, the nonlocal signal can be observed even at a spacing distance of 20 μm, demonstrating the potential of insulating antiferromagnet for the long distance spin transport.