Graphene-Enabled Detection of Weak Magnetic Order in Two-Dimensional Antiferromagnets

Magnetic van der Waals materials offer an exceptional platform for exploring low-dimensional magnetism and device concepts, enabled by their weak interlayer bonding and the resulting accessibility of monolayer and few-layer limits. Yet, as these systems are thinned, their magnetic signals diminish rapidly, rendering conventional bulk probes such as SQUID magnetometry ineffective and restricting transport-based approaches to intrinsically conducting samples. Graphene Hall sensors provide a powerful route to overcome these limitations: near charge neutrality, graphene exhibits ultrahigh mobility and minimal background signal, enabling sensitive detection of minute magnetic responses. In this talk, I will discuss about graphene-based Hall bar sensors capable of probing magnetic transition of an antiferromagnet, FePS3, through AC magnetic susceptibility measurements, despite magnetic signals more than two orders of magnitude weaker than typical vdW ferromagnets. Our results extend the reach of Hall-based susceptometry to insulating antiferromagnets and establish graphene sensors as a versatile platform for probing fragile magnetic order across the broader family of two-dimensional materials.