  The ability to switch magnetic elements by spin-orbit-induced torques has
recently attracted much attention for a path towards high-performance,
non-volatile memories with low power consumption. Realizing efficient
spin-orbit-based switching requires harnessing both new materials and novel
physics to obtain high charge-to-spin conversion efficiencies, thus making the
choice of spin source crucial. Here we report the observation of spin-orbit
torque switching in bilayers consisting of a semimetallic film of 1T'-MoTe2
adjacent to permalloy. Deterministic switching is achieved without external
magnetic fields at room temperature, and the switching occurs with currents one
order of magnitude smaller than those typical in devices using the
best-performing heavy metals. The thickness dependence can be understood if the
interfacial spin-orbit contribution is considered in addition to the bulk spin
Hall effect. Further threefold reduction in the switching current is
demonstrated with resort to dumbbell-shaped magnetic elements. These findings
foretell exciting prospects of using MoTe2 for low-power semimetal material
based spin devices.
