Giant Tunneling Magnetoresistance in Antiferromagnetic Tunnel Junctions with Non-collinear Mn₃NiN Electrodes

Antiferromagnetic tunnel junctions (AFMTJs) offer a promising device concept for antiferromagnetic (AFM) spintronics [1]. Non-collinear antiferromagnets can provide large tunneling magnetoresistance (TMR) in these junctions due to their extraordinary spin polarization [2]. In this work, first-principles calculations are performed to explore the performance of non-collinear antiferromagnet Mn₃NiN as an electrode in AFMTJs. Mn₃NiN benefits from its spin-split band structure, providing highly spin-polarized conduction channels in its (001) 2D Brillouin zone. When incorporated into AFMTJ, these properties contribute to the significant enhancement of TMR compared to conventional MTJs. As the result, a giant TMR, exceeding 2000%, is predicted for Mn₃NiN/LaAlO₃/Mn₃NiN (001) AFMTJs. This performance is attributed to the nearly 100% spin polarization of Mn₃NiN around the center of the 2D Brillouin zone, which aligns with the low decay rate profile of LaAlO₃, allowing for highly efficient spin-dependent tunneling. This work demonstrates the potential of Mn₃NiN-based AFMTJs as an effective framework for high-performance spintronic devices.