  We develop a theoretical formula of spin Hall torque in the presence of two
ferromagnets. While the direction of the conventional spin Hall torque always
points to the in-plane direction, the present system enables to manipulate the
torque direction acting on one magnetization by changing the direction of
another magnetization. Based on the diffusion equation of the spin accumulation
and the Landauer formula, we derive analytical formula of the spin Hall torque.
The present model provides a solution to switch a perpendicular ferromagnet
deterministically at zero field using the spin Hall effect.
