Thickness modulations enable multi-functional spin valves based on Van der Waals hetero-structure

Spintronic devices serve as important components of the next-generation large scale integrated circuits, but until today, spintronic devices of different kinds can only be realized by using different materials and structures, methods of controlling device properties and realizing different functions of devices are still wanted. Here, we report on the first realization of spin valves with three distinct magnetoresistance behaviors in a single hetero-structure of Fe3GeTe2 (FGT)/Nb-doped MoS2 (MoS2: Nb)/FGT by varying the thickness of the sandwiched MoS2: Nb layer. We propose a possible scenario for the spacer layer’s functions and corresponding mechanisms of three different types of spin valves, where the MoS2: Nb layer works as a tunneling barrier, a spin-filter, and a spin potential keeper, respectively. This work demonstrates a novel and promising method for controlling the spin valve properties and functions in a single material and structure system, which significantly benefits the integration of spin devices on a single micro-chip. More importantly, we propose a novel method to tune the properties of different types of spintronic devices. [Display omitted] •Multi-types spin valves are realized in one single material system and device structure.•Band structure of the spacer layer determines transport performance of the spin valve.•By using band engineering method like varying the thickness of the spacer layer, the transport performance of the spin valve can be modulated.