Antiferromagnetic Magnon Drag Effect and Giant On-Off Ratio in a Vertical Device

Antiferromagnets offer unique advantages in the development of spintronics because of the absence of stray field, insensitivity to external disturbances and the ultrafast terahertz eigenfrequency, advancing the development of devices toward small-size and high-speed. However, the ultralow read-out signals of antiferromagnetic spintronics are notoriously smaller than their ferromagnetic counterpart, seriously hindering the development of antiferromagnets. Thus, experimental realization of large read-out signals in antiferromagnets, especially in vertical devices, is intensely pursued. Here the antiferromagnetic magnon drag effect and a giant on-off ratio of approximate to 1000 are realized in a vertical sandwich structure of heavy metal/antiferromagnetic insulator/heavy metal (Pt/alpha-Fe2O3/Pt). The read-out signal can exist up to room temperature, and the detected signal owing to the transmission and blocking of magnon strongly relies on the relative orientation between spin polarization and Neel vector. Benefiting from the nonvolatile characteristic of Fe2O3, zero-field vertical magnon transport is achieved. The giant on-off signals in vertical devices that can be tightly packed, can greatly promote the practical application of antiferromagnetic magnon devices toward smaller, faster, and lower energy consumption.