Intrinsic exchange bias in van der Waals alloy Cr0.45Pt0.55Te2

Two-dimensional van der Waals magnetic materials are of recent interest for scientific and technological applications. The novelty in two dimensional magnetic materials means there are new paradigms and functionalities that have yet to be explored, including atomically thick layered structures. Here we report evidence of a novel magnetic structure in exfoliatable van der waals magnetic alloy Cr0.45Pt0.55Te 2 (CPT). We use magneto-optic measurements to observe hysteresis loops in exfoliated CPT samples. The most notable attribute of CPT's hysteresis is that the loop is not centered at zero. We interpret this as an exchange bias effect, reminiscent of heterostructures of ferromagnets and antiferromagnets, but intrinsic to this material. We explain this effect as a layer-by-layer system of coupled ferromagnetic layers, exerting exchange bias on each other. This work demonstrates layer by layer exchange bias effects that pave the way for further understanding exchange in two dimensional systems.