Room-temperature orbit-transfer torque enabling van der Waals magnetoresistive memories

The non-volatile magnetoresistive random access memory (MRAM) is believed to facilitate emerging applications, such as in-memory computing, neuromorphic computing and stochastic computing. Twodimensional (2D) materials and their van der Waals heterostructures promote the development of MRAM technology, due to their atomically smooth interfaces and tunable physical properties. Here we report the all-2D magnetoresistive memories featuring all-electrical data reading and writing at room temperature based on WTe2/Fe3GaTe2/BN/Fe3GaTe2 heterostructures. The data reading process relies on the tunnel magnetoresistance of Fe3GaTe2/BN/Fe3GaTe2. The data writing is achieved through current induced polarization of orbital magnetic moments in WTe2, which exert torques on Fe3GaTe2, known as the orbit-transfer torque (OTT) effect. In contrast to the conventional reliance on spin moments in spintransfer torque and spin-orbit torque, the OTT effect leverages the natural out-of-plane orbital moments, facilitating field-free perpendicular magnetization switching through interface currents. Our results indicate that the emerging OTT-MRAM is promising for low-power, high-performance memory applications.(c) 2023 Science China Press. Published by Elsevier B.V. and Science China Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).