Twist-engineered interfacial coupling for tailorable large exchange bias in stacked oxide heterostructures

The establishment and tuning of artificial spin configurations at interfaces constitute a pivotal goal within the field of condensed-matter physics, primarily geared toward the advancement of emerging spintronic devices. However, the interfacial magnetic interaction in traditional epitaxial heterostructures remains static and non-adjustable. Here, we demonstrate the strong interfacial magnetic coupling in the stacked La_0.67Sr_0.33MnO₃ (LSMO)/NiO heterostructures, which feature near-atomic-level contact, both fabricated as transferable, single-crystal, freestanding oxide membranes. Meanwhile, we introduce effective approaches to engineer exchange bias by altering the interface distance and stacking angle between LSMO and NiO. Our results reveal a pronounced dependence of the exchange bias magnitude (H_eb) in stacked LSMO/NiO heterostructures on the twist angle, peaking at 180 Oe at a twist angle of 20°, a value 1.8 times greater than that observed in rigid LSMO/NiO heterostructures. Our work underscores robust strategies for establishing magnetic interactions at an all-oxide van der Waals interface benefiting the printable and reconfigurable devices through twist angle manipulation.