Controllable Spin-Transfer Torque on an Antiferromagnet in a Dual Spin-Valve

We consider current-induced spin-transfer torque on an antiferromagnet in a dual spin-valve setup. It is demonstrated that a net magnetization may be induced in the AFM by partially or completely aligning the sublattice magnetizations via a current-induced spin-transfer torque. This effect occurs for current densities ranging below 10$^6$ A/cm$^2$. The direction of the induced magnetization in the AFM is shown to be efficiently controlled by means of the magnetic configuration of the spin-valve setup, with the anti-parallell configuration yielding the largest spin-transfer torque. Interestingly, the magnetization switching time-scale $\tau_\text{switch}$ itself has a strong, non-monotonic dependence on the spin-valve configuration. These results may point toward new ways to incorporate AFMs in spintronic devices in order to obtain novel types of functionality.