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Abstract Giant spin–orbit torque (SOT) from topological insulators (TIs) has great potential for low‐power SOT‐driven magnetic random‐access memory (SOT‐MRAM). In this work, a functional 3‐terminal SOT‐MRAM device is demonstrated 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. An 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.
Cui et al. (Thu,) studied this question.