Antiferromagnetic V2O3 based exchange coupling

Vanadium sesquioxide (V₂O₃) is a strongly correlated electronic material that famously undergoes a triple coupled first-order transition where it transitions from a paramagnetic metal with a rhombohedral structure at high temperature to an antiferromagnetic insulator with a monoclinic structure. While several studies have used one of both electronic and structural transitions to control the properties of a heterostructure, evidence of magnetic coupling has notoriously yet to be found. In this paper, we report on a robust magnetic coupling between the antiferromagnetic (AFM) V₂O₃ and ferromagnetic (FM) Permalloy (Py) layers that results in a significant exchange bias and strain-induced coercivity enhancement. We provide a temperature and angle-dependent study of magnetic properties, which clearly indicates exchange bias at the AFM/FM interface that appears at the onset of the metal-insulator transition. The magnitude of the exchange bias is strongest when the field is applied along the [001] V₂O₃ crystallographic orientation which corresponds to an AFM spin configuration on the [110] surface. This opens the door to designing and implementing novel functionalities in transition metal oxide-based computing using the connection between magnetism and the metal-insulator transition.