Spin-flop transition in the quasi-two-dimensional antiferromagnet MnPS3 detected via thermally generated magnon transport

Abstract

We present the detection of the spin-flop transition in the antiferromagnetic van der Waals material MnPS 3 via thermally generated nonlocal magnon transport using permalloy (Py) detector strips. Py detector strips possess the inverse anomalous spin Hall effect, which has the unique power to detect an out-of-plane spin accumulation [Das et al., Nano Lett. 18, 5633 (2018)]. This enables us to detect magnons with an out-of-plane spin polarization, in contrast to strips of high-spin-orbit materials such as Pt which possess only the spin Hall effect and are sensitive to only an in-plane spin polarization of the spin accumulation. We show that nonlocal magnon transport is able to measure the spin-flop transition in the absence of spurious magnetoresistance effects. Our measurements show the detection of magnons generated by the spin Seebeck effect before and after the spin-flop transition. We observe a signal reversal of the magnon spin accumulation which agrees with the out-of-plane spin polarization carried by magnon modes before and after the spin-flop transition.