MnSnN-Based Antiferromagnetic Tunnel Junction with Giant Tunneling Magnetoresistance and Multi-States: Design and Theoretical Validation.

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 MnSnN/SrTiO/MnSnN 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 MnSnN electrode and the low-decay-rate evanescent states of the SrTiO 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 MnSnN magnetic orders leads to four non-volatile resistance states with a low resistance area (RA) of only 0.07-1.25 Ω•µm 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.