Voltage-controlled tunneling magnetoresistance in all-antiferromagnetic tunnel junctions based on noncollinear antiferromagnet Mn₃Sn

Unlike traditional antiferromagnetic materials (AFMs), kagome-based non-collinear antiferromagnets (NCAFs) (Mn_3X, X =\rm Sn, Ge, Ga, etc.) exhibit a local spin-splitting effect and ultrafast dynamics, which are expected to enable the construction of all-antiferromagnetic tunnel junctions (AATJs) with negligible stray fields. Herein, we revealed the non-collinear magnetization switching mechanisms of Mn_3Sn and constructed the AATJs models with Mn_3Sn as free layer and reference layer by employing the non-equilibrium Green's function combined with density-functional theory. We achieved tunnelling magnetoresistance (TMR) ratios of approximately 131% at room temperature in Mn_3Sn/MgO/Mn_3Sn structure by manipulation of their Néel vectors. Particularly, we explored the dependence of TMR on bias voltages in non-equilibrium states, and the results show the TMR ratio can be regulated from 42% to 20% by applied bias. Our work presents the great potential of developing MRAM with ultra-high-speed, low-power consumption and high-density integration based on non-collinear antiferromagnets as the core functional units.