Interface-controlled antiferromagnetic tunnel junctions
Yang Liu, Yuanyuan Jiang, Xiaoyan Guo, Shu‐Hui Zhang, Rui‐Chun Xiao, W. J. Lu, Lan Wang, Yuping Sun, Evgeny Y. Tsymbal, Ding‐Fu Shao
Abstract
Magnetic tunnel junctions (MTJs) are essential components of high-performance spintronic devices. While conventional MTJs use ferromagnetic materials, antiferromagnetic (AFM) compounds can significantly increase operation speed and packing density. Current AFM tunnel junctions (AFMTJs) exploit antiferromagnets as spin-filter barriers or metal electrodes with bulk spin-dependent currents. Here, we highlight a largely overlooked AFMTJ prototype with bulk-spin-degenerate electrodes exhibiting A-type AFM stacking, forming magnetically uncompensated interfaces that enable spin-polarized tunneling currents and a sizable tunneling magnetoresistance (TMR). Using first-principles quantum-transport calculations and van der Waals (vdW) metal Fe 4 GeTe 2 as an example, we demonstrate a large negative TMR from interfacial magnetic moment alignment. This prototype can also be realized with non-vdW A-type AFM metals featuring roughness-insensitive surface magnetization. Beyond TMR, these AFMTJs allow convenient switching of the Néel vector, opening new avenues for AFM spintronics based on interface-driven spin-dependent properties.