Current-induced spin-orbit torques (SOTs) enable fast and efficient manipulation of the magnetic state of magnetic tunnel junctions (MTJs), making it attractive for memory, in-memory computing, and logic applications. However, the requirement of the external magnetic field to achieve deterministic switching in perpendicular magnetized SOT-MTJs limits its implementation for practical applications. Here, we introduce a field-free switching (FFS) solution for the SOT-MTJ device by shaping the SOT channel to create a "bend" in the SOT current. The resulting bend in the charge current creates a spatially non-uniform spin current, which translates into inhomogeneous SOT on an adjacent magnetic free layer enabling deterministic switching. We demonstrate FFS experimentally on scaled SOT-MTJs at nanosecond time scales. This proposed scheme is scalable, material-agnostic, and readily compatible with wafer-scale manufacturing, thus creating a pathway for developing purely current-driven SOT systems.
@article{arxiv.2305.03961,
title = {Field-Free Spin-Orbit Torque driven Switching of Perpendicular Magnetic Tunnel Junction through Bending Current},
author = {Vaishnavi Kateel and Viola Krizakova and Siddharth Rao and Kaiming Cai and Mohit Gupta and Maxwel Gama Monteiro and Farrukh Yasin and Bart Sorée and Johan De Boeck and Sebastien Couet and Pietro Gambardella and Gouri Sankar Kar and Kevin Garello},
journal= {arXiv preprint arXiv:2305.03961},
year = {2023}
}