Probing Magnetic Domains in Two-dimensional Magnets via Electric Transport

The recently discovered van der Waals (vdW) magnets provide new opportunities for studying  magnetism at the 2D limit and designing novel spin devices. However, the role of magnetic domains in few-layer vdW magnets has been largely ignored. Here, we report the fabrication of high-quality magnetic tunneling devices based on 2D magnets and a systematic study of the tunneling magnetoresistances (TMR). In the TMR results, we not only observed the layer-dependent magnetization switching-induced large step-like resistance changes, but also identified a few mini step-like resistance changes. We further found that the corresponding coercivities and magnitudes of the mini step-like resistance changes are highly dependent on the cooling history of the device as well as the tunneling current. We attribute these observations to the appearance of magnetic domains in the few layer 2D magnets. Our results may shed some light on understanding the novel magnetism at low dimensions.