  Spin transfer torques allow the electrical manipulation of the magnetization
at room temperature, which is desirable in spintronic devices such as spin
transfer torque memories. When combined with spin-orbit coupling, they give
rise to spin-orbit torques which are a more powerful tool for magnetization
control and can enrich device functionalities. The engineering of spin-orbit
torques, based mostly on the spin Hall effect, is being intensely pursued. Here
we report that the oxidation of spin-orbit torque devices triggers a new
mechanism of spin-orbit torque, which is about two times stronger than that
based on the spin Hall effect. We thus introduce a way to engineer spin-orbit
torques via oxygen manipulation. Combined with electrical gating of the oxygen
level, our findings may also pave the way towards reconfigurable logic devices.
