Spin-Valve Effect in Fe₃GeTe₂/MoS₂/Fe₃GeTe₂ van der Waals Heterostructures

The van der Waals (vdW) materials offer an opportunity to build all-two-dimensional (all-2D) spintronic devices with high-quality interfaces regardless of the lattice mismatch. Here, we report on an all-2D vertical spin valve that combines a typical layered semiconductor MoS₂ with vdW ferromagnetic metal Fe₃GeTe₂ (FGT) flakes. The linear current-voltage curves illustrate that Ohmic contacts are formed in FGT/MoS₂ interfaces, while the temperature dependence of the junction resistance further demonstrates that the MoS₂ interlayer acts as a conducting layer instead of a tunneling layer. In addition, the magnitude of the magnetoresistance (MR) of 3.1% at 10 K is observed, which is around 8 times larger than that of the reported spin valves based on MoS₂ sandwiched by conventional ferromagnetic electrodes. The MR decreasing monotonically with increasing temperature follows the Bloch's law. As the bias current decreases exponentially, the MR increases linearly up to a maximum value of 4.1%. Our results reveal the potential opportunities of vdW heterostructures for developing novel spintronic devices.