The Spontaneous and Tunable Exchange Bias in above Room-Temperature Van der Waals Magnet

Van der Waals (vdW) magnets have opened up new avenues for exploring next-generation spintronic devices. The exchange bias (EB) effect plays an undisputed role in ensuring accurate data retrieval in spintronic devices. However, the unsustainably weak EB field (H_EB) introduced by field cooling and the high-complexity of devices incompatible with silicon-based industry, limit the application of related vdW spintronic devices. Here, a compatible and simple method is reported for constructing Fe₃GaTe₂/oxidized Fe₃GaTe₂ heterostructures and achieving a spontaneous EB effect with a low-complexity device configuration. The spontaneous EB effect exhibits undecayed, tunable, and giant H_EB of 2550 Oe at 3 K, along with a relatively high blocking temperature of 220 K. Field cooling and cross-sectional microstructure studies suggest that the EB effect arises from antiferromagnetic exchange coupling between Fe₃GaTe₂ and spin clusters frozen by α-Fe₂O₃ at the disordered interface. This work provides a unique avenue for customizing, integrating, and producing related spintronic devices.