Enhancement of spin-orbit torque in WTe2/perpendicular magnetic anisotropy heterostructures

Spin-orbit torque (SOT), exerted to a ferromagnet from an adjacent non-magnetic layer, has been widely considered as a promising strategy to realize spintronic devices with high energy efficiency, endurance, and speed. Much effort has been devoted to the search for materials and structures that can generate strong SOTs. Recent investigations showed that two-dimensional (2D) transition metal dichalcogenides provide the potential to produce strong enough SOTs to manipulate the magnetic devices due to rich spin-dependent properties. Here, we present the study of SOT in WTe2/ferromagnet with perpendicular magnetic anisotropy devices, and an enhancement of SOT efficiency with the thickness of WTe2 is observed, which may be ascribed to the spin absorption at the WTe2/Ta interface and the spin Hall effect. This work demonstrates the possibility of manipulating magnetization by 2D materials and an avenue for engineering spintronic devices based on 2D materials.