Unconventional magnon transport in antiferromagnet NiPS$_3$ induced by an anisotropic spin-flop transition

TL;DR

This study demonstrates how an anisotropic spin-flop transition in NiPS$_3$ influences nonlocal magnon transport, revealing sharp directional jumps and decay behavior, advancing understanding of magnetic phase transitions in van der Waals antiferromagnets.

Contribution

It provides the first experimental observation of unconventional magnon transport driven by an anisotropic spin-flop transition in a van der Waals antiferromagnet.

Findings

Sharp jumps in nonlocal voltage at specific directions due to spin-flop transition

Magnon signal exhibits a 1/d$^2$ decay in thin NiPS$_3$

Electrical detection effectively probes magnetic phase transitions

Abstract

Nonlocal magnon transport can provide valuable insight into the magnetic properties of magnetic insulators (MIs). A spin-flop transition, a typical magnetic reorientation in antiferromagnets, is expected to affect mag non transport, but studies on this topic are still rare and remain challenging, especially for van der Waals materials. Here we demonstrate the unconventional magnon transport driven by an anisotropic spin-flop transition in the van der Waals antiferromagnet NiPS$_3$. Examining the nonlocal voltage from thermally driven magnons reveals sharp jumps at certain directions when an inplane magnetic field aligns with the b-axis of NiPS$_3$, attributed to an in-plane anisotropic spin-flop transition. Furthermore, thermally driven magnon signal exhibits a 1/d$^2$ decay in thin NiPS$_3$, evidencing that it is dominated by the intrinsic spin Seebeck effect. Our findings highlight that the electrical detection of magnon currents in a nonlocal device geometry serves as a powerful approach for studying magnetic phase transitions in MIs.