  Electrical gate-manipulated exchange bias (EB) effect is a long-term goal for
spintronics applications. Meanwhile, the emergence of van der Waals (vdW)
magnetic heterostructures provides ideal platforms for the study of interlayer
magnetic coupling. However, to date, the electrical gate-controlled EB effect
has yet to be realized in vdW heterostructures. Here, for the first time, we
realized electrically-controllable EB effects in a vdW antiferromagnetic
(AFM)-ferromagnetic (FM) heterostructure, FePS3-Fe5GeTe2. For pristine
FePS3-Fe5GeTe2 heterostructures, sizable EB effects can be generated due to the
strong interface coupling, which also depend on the thickness of the
ferromagnetic layers. By applying a solid protonic gate, the EB effects can be
electrically tuned largely by proton intercalations and deintercalations. The
EB field reaches up to 23% of the coercive field and the blocking temperature
exceeds 50 K at Vg= -3.15 V. The proton intercalations not only tune the
average magnetic exchange coupling, but also change the AFM configurations and
transform the heterointerface between an uncompensated AFM-FM interface and a
compensated AFM-FM interface. These alterations result in a dramatic modulation
of the total interface exchange coupling and the resultant EB effects. The
study is a significant step towards vdW heterostructure-based magnetic logic
for future low-energy electronics.
