We propose analytic expressions for fieldlike, $T_{\perp }$, and spin-transfer, $T_{\parallel }$, spin torque components in the spin-filter-based magnetic tunnel junction (SFMTJ), by using the single-band tight-binding model with the nonequilibrium Keldysh formalism. In consideration of multireflection processes between noncollinear magnetization of the spin-filter (SF) barrier and the ferromagnetic (FM) electrode, the central spin-selective SF barrier plays an active role in the striking discovery $T_{\perp }\gg T_{\parallel }$, which can be further identified by the unusual barrier thickness dependence of giant $T_{\perp }$. Our general expressions reveal the sinusoidal angular dependence of both spin torque components, even in the presence of the SF barrier.

• Received 26 March 2017

DOI:https://doi.org/10.1103/PhysRevB.96.064429