Magnetoresistance and Hall Resistance Hysteresis in the 2D Heavy Fermion Antiferromagnet CeSiI

The recent discovery of the intrinsic 2D heavy fermion and frustrated antiferromagnet CeSiI has opened a plethora of opportunities to explore the interplay between magnetism and the Kondo effect at low dimensions. The ability to exfoliate CeSiI to the atomically thin limit presents additional opportunities, such as gating and fabrication of heterostructures, to explore this phase space and access a quantum critical point. In this work, we fabricate CeSiI devices ranging from bulk to bilayer unit cell thicknesses and utilize electronic transport and magnetic susceptibility measurements to explore the magnetic behavior. Across all devices, we measure a hysteresis in the magnetoresistance and hall resistance, which we attribute to magnetic ordering. We observe a time dependent contribution to the hysteresis, which implies the presence of magnetic structures other than antiferromagnetic ordering, as well as a time independent contribution. Interestingly, this time dependent hysteresis is most pronounced in the magnetoresistance, where it persists at fields higher than the two metamagnetic transitions. Furthermore, this hysteresis emerges at temperatures above the 8K Néel temperature, reaches a maximum around 3-4K, and diminishes at 0.3 K.