Injecting, Transmitting and Detecting Magnons Through a 2D Antiferromagnet/Graphene Heterostructure Using Non-Local Transport and Edge States

Antiferromagnetic insulators harbor spin waves, or magnons, the manipulation of which offers a potential pathway to transmit information in an energy-efficient manner. In this work we developed a new experimental method to generate and detect magnons in a van der Waals antiferromagnet/graphene heterostructure using pure electrical transport means and exploiting the spin polarized quantum Hall edge states of graphene. Magnons are injected at a MnPS₃/bilayer graphene interface, transmitted through a pristine MnPS₃ region, and detected by another MnPS₃/graphene interface. Both linear and second order non-local responses are observed and we report injection/detection efficiency several orders of magnitude higher than the conventional (inverse)spin Hall setup. The magnetic field induced phase transition of the MnPS₃ impacts the sign and amplitude of the magnon signal. By analyzing the temperature dependence of the observed signal, we extract the Gilbert damping coefficient of MnPS₃, which is ~ 0.01 in our sample. This method can potentially be generaled to probe the magnetic order and low energy excitations of other van der Waals magnets.