Proximity Effect-Induced Magnetoresistance Enhancement in a Fe 3 GeTe 2 /NbSe 2 /Fe 3 GeTe 2 Magnetic Tunnel Junction.

The coupling between van der Waals-layered magnetic and superconducting materials holds the possibility of revealing novel physical mechanisms and realizing spintronic devices with new functionalities. Here, we report on the realization and investigation of a maximum ∼17-fold magnetoresistance (MR) enhancement based on a vertical magnetic tunnel junction of Fe 3 GeTe 2 (FGT)/NbSe 2 /FGT near the NbSe 2 layer's superconducting critical temperature ( T C ) of 6.8 K. This enhancement is attributed to the band splitting in the atomically thin NbSe 2 spacer layer induced by the magnetic proximity effect on the material interfaces. However, the band splitting is strongly suppressed by the interlayer coupling in the thick NbSe 2 layer. Correspondingly, the device with a thick NbSe 2 layer displays no MR increase near T C but a current dependent on transport properties at extremely low temperatures. This work carefully investigates the mechanism of MR enhancement, paving an efficient way for the modulation of spintronics' properties and the achievement of spin-based integrated circuits.