Abstract
Exchange bias (EB) in antiferromagnetic (AFM)/ferromagnetic heterostructures is crucial for the advancement of spintronic devices and has attracted significant attention. The common EB effect in van der Waals heterostructures features a low blocking temperature (T(b)) and a single polarity. In this work, a significant EB effect with a T(b) up to 150 K is observed in FePS(3)/Fe(3)GaTe(2) heterostructures, and in particular, the EB exhibits an unusual temperature-dependent polarity-reversal behavior. Under a high positive field-cooling condition (e.g., μ(0)H ≥ 0.5 T), a negative EB field (H(EB)) is observed at low temperatures, and with increasing temperature, the H(EB) crosses zero at ≈20 K, subsequently becomes positive and later approaches zero again at T(b). A model composed of a top FePS(3)/interfacial FePS(3)/Fe(3)GaTe(2) sandwich structure is proposed. The charge transfer from Fe(3)GaTe(2) to FePS(3) at the interface induces net magnetic moments (∆M) in FePS(3). The interface favors AFM coupling, and thus the reversal of ∆M of the interfacial FePS(3) leads to the polarity-reversal of EB. Moreover, the EB can be extended to the bare Fe(3)GaTe(2) region of the Fe(3)GaTe(2) flake partially covered by FePS(3). This work provides opportunities for a deeper understanding of the EB effect and opens a new route toward constructing novel spintronic devices.