Thermal magnon transport in van der Waals antiferromagnetic CrPS4

Abstract

Magnons in insulating antiferromagnets hold great promise for low-dissipation spintronics, also known as magnonics. Yet, the understanding of their generation and transport behaviors in the emerging two-dimensional (2D) van der Waals (vdW) systems remains limited. Here, we report the systematic study on the thermal magnon transport in the A-type vdW antiferromagnet CrPS4 using the nonlocal detection method. We demonstrate a magnon propagation length of 6.8 μm in 50-nm-thick samples at 2 K, exceeding most previously reported values in antiferromagnets. Temperature-dependent studies reveal a threefold reduction in magnon diffusion length from 6.8 μm (2 K) to 1.6 μm (20 K) at elevated temperature, which is attributed to enhanced magnon–phonon scattering. Thickness-dependent measurements reveal a monotonically increasing diffusion length as film thickness increases, which suggests that surface scattering may significantly suppress magnon propagation in thin samples. These observations improve our understanding of magnon transport in vdW antiferromagnets and establish CrPS4 as a promising platform for future magnonics.