Low-power and Field-free Perpendicular Magnetic Memory Driven by Topological Insulators.

Giant spin-orbit torque (SOT) from topological insulators (TIs) has great potential for the low-power SOT-driven magnetic random-access memory (SOT-MRAM). Here, we demonstrate the functional 3-terminal SOT-MRAM device by integrating the TI [(BiSb) 2 Te 3 ] with perpendicular magnetic tunnel junctions (pMTJs), where the tunneling magnetoresistance is employed for the effective reading method. The ultralow switching current density of 1.5 × 10 5 A cm -2 is achieved in the TI-pMTJ device at room temperature, which is 1-2 orders of magnitude lower than that in conventional heavy metals-based systems, due to the high SOT efficiency θ SH = 1.16 of (BiSb) 2 Te 3 . Furthermore, all-electrical field-free writing is realized by the synergistic effect of a small spin-transfer torque current during the SOT. The thermal stability factor (Δ = 66) shows the high retention time (> 10 years) of the TI-pMTJ device. This work sheds light to the future low-power, high-density, and high-endurance/retention magnetic memory technology based on quantum materials. This article is protected by copyright. All rights reserved.