Interface-Induced Magnetization Reversal and Multistate Magnetoresistance in Fe₃GaTe₂/Ni₈₀Fe₂₀ Heterostructure

Mixed-dimensional heterostructures integrating two-dimensional (2D) van der Waals magnets with conventional ferromagnetic films unify the versatile functionalities of both material classes and offer enormous potential for magnetic sensing, non-volatile data storage, and reconfigurable spintronic devices. More importantly, 2D domain evolution can modulate the magnetization reversal and magnetotransport of the adjacent ferromagnetic layer through interface engineering. Here, we construct a vertically stacked Fe₃GaTe₂/Ni₈₀Fe₂₀ (Permalloy, Py) heterostructure. Magnetometry measurements confirm the magnetic anisotropies of both constituents and labyrinthine domains in Fe₃GaTe₂. Compared with the narrow, one-step low-field anisotropic magnetoresistance features of isolated Py, the heterostructure exhibits multipeak resistance responses and pronounced hysteresis. Asymmetric minor-loop field-sweeping measurements further reveal a strong dependence on the positive maximum field, which modifies the loop morphology and produces distinct remanent resistance states at zero field. These observations are consistent with a domain-mediated interfacial pinning mechanism, in which Fe₃GaTe₂ domains and domain walls modify the interfacial magnetic environment, thereby pinning adjacent Py moments and promoting their progressive, multistep reversal. These findings provide a route toward multistate spintronic devices based on mixed-dimensional magnetic heterostructures.