Symmetry-dependent field-free switching of perpendicular magnetization

Modern magnetic-memory technology requires all-electric control of perpendicular magnetization with low energy consumption. While spin–orbit torque (SOT) in heavy metal/ferromagnet (HM/FM) heterostructures1–5 holds promise for applications magnetic random access memory, until today, it has been limited to the in-plane direction. Such can switch only deterministically help additional symmetry breaking, example, through application an external field2,4, interlayer/exchange coupling6–9 or asymmetric design10–14. Instead, out-of-plane SOT15 could directly magnetization. Here we observe SOT HM/FM bilayer L11-ordered CuPt/CoPt and demonstrate field-free switching CoPt layer. The low-symmetry point group (3m1) at interface gives rise this spin torque, hereinafter referred as 3m which strongly depends on relative orientation current flow crystal symmetry. We a three-fold angular dependence both current-induced effective field. Because intrinsic nature shows good endurance cycling experiments. Experiments involving wide variety bilayers groups16,17 may reveal further unconventional torques future. Spin–orbit heterostructures is promising but so far required breaking design give deterministically.