Antisymmetric Tunneling Magnetoresistance in Van der Waals Fe ₃ GeTe ₂ /Nb ₃ Cl ₈ /Fe ₃ GeTe ₂ Heterostructures Driven by Spin‐Splitting Potential Barrier

Abstract Spintronic circuits exploit electronic spin other than charge as an information carrier, consuming several orders of magnitude less energy than conventional electronic circuits. 2D ferromagnets and topological material harbor spin polarization and spin dependent transport properties, bearing great application potential in spintronic devices. Among them, Fe 3 GeTe 2 is a well‐known van der Waals ferromagnetic material. Nb 3 Cl 8 is an emerging topological semiconducting material with a van der Waals layered structure, which enables 2D heterostructure composition and CMOS fabrication compatible. Here, the observation of antisymmetric tunneling magnetoresistance is reported in van der Waals Fe 3 GeTe 2 /Nb 3 Cl 8 /Fe 3 GeTe 2 heterostructures with a semiconductor as the intermediate tunnelling layer. Unlike previous studies, the antisymmetric magnetoresistance can be tuned to be symmetric through both temperature or bias current. Such an antisymmetric magnetoresistance phenomenon can be explained by the dominant spin splitting in the electronic band structure of the Nb 3 Cl 8 barrier layer. Meanwhile, the bias current across the heterojunction affects the coercive field of Fe 3 GeTe 2 with varying thicknesses and leads to the emergence of exchange bias, resulting in the magnetoresistance transitioning from antisymmetric to symmetric. The work thus not only provides a new material platform but also shines light on the physical mechanism of exotic magnetic tunnel junction devices for spintronic applications.