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 (HEB) 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 HEB 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 alpha-Fe2O3 at the disordered interface. This work provides a unique avenue for customizing, integrating, and producing related spintronic devices.