Large tunneling magnetoresistance and low resistance-area product in CrSe_2/NiCl_2/CrSe_2 van der Waals magnetic tunnel junction

摘要

The emergence of two-dimensional van der Waals (vdW) intrinsic magnets offers exciting opportunities to explore high-performance vdW magnetic tunnel junctions (vdW MTJs) and miniaturization of devices beyond Moore's law for future energy efficient nano-electronic devices. In this work, using first principles calculations, we investigate the spin-dependent transport of vdW MTJs formed by two vdW ferromagnetic (FM) CrSe_2 electrodes and an interlayer antiferromagnetic bilayer NiCl_2 barrier (CrSe_2/NiCl_2/CrSe_2 vdW MTJ). We find that in contrast to the large resistance-area (RA) products higher than several kilohms square micrometer in crystalline MgO based MTJs with high tunneling magnetoresistance (TMR) ratios, the large TMR ratio of about 5200 and the low RA products ranging from 0.11 to 6 Ω μm~2 are simultaneously achieved in the CrSe_2/NiCl_2/CrSe_2 vdW MTJ at zero bias due to the spin-dependent tunnel transport associated with the FM CrSe_2 electrode and the significant spin filtering effect associated with the half-metallic bilayer NiCl_2 barrier. Moreover, the TMR ratio of the CrSe_2/NiCl_2/CrSe_2 vdW MTJ increases first with increasing bias voltage and then decreases with the further increase in the bias voltage after reaching the highest value, and the optimized bias voltage can significantly promote the TMR ratio up to 12 000. Our results pave the way to develop high-performance vdW MTJs with both large TMR ratios and low RA products for future spintronic applications.