The manipulation of exchange bias in van der Waal ferromagnetic/antiferromagnetic heterojunction by interfacial coupling

Abstract

Two-dimensional (2D) van der Waals (vdWs) heterostructures, with their atomically sharp interfaces and low defect densities, offer an ideal platform for studying interfacial spin phenomena and enabling low-power spintronic devices. However, achieving controllable and reversible exchange bias (EB) in 2D systems remains challenging. Here, we report a pronounced EB effect in a vdWs ferromagnetic/antiferromagnetic (FM/AFM) heterojunction composed of Fe₃GaTe₂/CrPS₄, with the EB field reaching up to 850 Oe at 10 K. More importantly, we observe a temperature-driven reversal of the EB field direction from negative to positive, a rare phenomenon in 2D heterostructures. To explain this behavior, we propose a model in which spin-canted uncompensated moments in CrPS₄ compete with asynchronous magnetization reversal between the surface and bulk regions of Fe₃GaTe₂, leading to a tunable EB response. Furthermore, the sign and magnitude of EB can be precisely controlled by adjusting temperature and ferromagnetic layer thickness under the same cooling field. This work reveals the fundamental role of interfacial exchange interactions and provides guidance for designing programmable magnetic states in next-generation spintronic devices.