Reconfigurable Room-Temperature Exchange Bias through Néel Order Switching in van der Waals Heterostructures.

Exchange bias (EB) effects play a crucial role in modern magnetic memory technology. Recently, the van der Waals heterostructures have shown potential for investigating mechanisms of the EB effect owing to their tunable physical properties and flexibility in fabrication. However, due to low magnetic ordering temperatures for most van der Waals magnets, establishing EB in van der Waals antiferromagnet/ferromagnet heterostructures at room temperature is challenging. In this study, we fabricate (FeCo)GeTe (FCGT)/FeGaTe (FGaT) heterostructures with magnetic ordering temperatures of each component well above room temperature to achieve a room-temperature EB effect. It is found that the sign and magnitude of the EB field can be efficiently controlled by manipulating the Néel order of FCGT. The manipulation of the Néel order shows significant magnetic field dependence. A strong preset field induces a switch in the Néel order of FCGT, which aligns the interfacial magnetization at the FCGT/FGaT interface, leading to robust EB, as revealed by both transport measurements and macrospin model calculations. Our findings demonstrate the intrinsic manipulation and switchability of room-temperature EB in all-van der Waals heterostructures and further emphasize the potential of two-dimensional spintronic devices.