Materials science

Perpendicular

Geometry

Physics

Torque

Ferromagnetism

Magnetization

Magnetic anisotropy

Mathematics

Spintronics

Quantum mechanics

Magnet

Magnetic field

Condensed matter physics

Nature Materials

Spin–orbit torque (SOT)-driven deterministic control of the magnetic state of a ferromagnet with perpendicular magnetic anisotropy is key to next-generation spintronic applications including non-volatile, ultrafast and energy-efficient data-storage devices. However, field-free deterministic switching of perpendicular magnetization remains a challenge because it requires an out-of-plane antidamping torque, which is not allowed in conventional spin-source materials such as heavy metals and topological insulators due to the system’s symmetry. The exploitation of low-crystal symmetries in emergent quantum materials offers a unique approach to achieve SOTs with unconventional forms. Here we report an experimental realization of field-free deterministic magnetic switching of a perpendicularly polarized van der Waals magnet employing an out-of-plane antidamping SOT generated in layered WTe2, a quantum material with a low-symmetry crystal structure. Our numerical simulations suggest that the out-of-plane antidamping torque in WTe2 is essential to explain the observed magnetization switching. The authors show that an out-of-plane antidamping spin–orbit torque can produce a sizeable change in the switching dynamics of a magnetic layer with perpendicular anisotropy.

Deterministic switching of a perpendicularly polarized magnet using unconventional spin–orbit torques in WTe2