Mn₃SnN-Based Antiferromagnetic Tunnel Junction with Giant Tunneling Magnetoresistance and Multi-States: Design and...

Antiferromagnets have attracted widespread interest due to the advantages of no stray fields and ultrafast switching dynamics, promising for next-generation high-speed, high-density memories. However, over a long period, the effective detection of antiferromagnetic (AFM) orders remained being one of the greatest challenges of its application in magnetic random access memories (MRAM) because of its zero net magnetization. Recently, the preliminary demonstration of the tunneling magnetoresistance ratio(TMR) in antiferromagnetic tunnel junctions (AFMTJ) offered a feasible solution. Here, a Mn₃SnN/SrTiO₃/Mn₃SnN non-collinear AFMTJ is designed and its transport properties are predicted by ab initio quantum transport simulations. Due to the momentum matching between the spin-polarized Fermi surface of the Mn₃SnN electrode and the low-decay-rate evanescent states of the SrTiO₃ barrier, a remarkable TMR ≈1500% is generated, corresponding to a large device read margin, resulting in higher storage density. In addition, changing the relative orientation of two Mn₃SnN magnetic orders leads to four non-volatile resistance states with a low resistance area (RA) of only 0.07-1.25 Ω•µm² and three multi-state TMR of ≈500, 1000, and 1500%, suitable for high-energy-efficiency multiple-state memory application. Our work provides a promising device structure for future nonvolatile high-speed, high-density, and multiple-state AFM memories.