  Spin transfer torque in magnetic structures occurs when the transverse
component of the spin current that flows from the nonmagnetic medium to
ferromagnetic medium are absorbed by the interface. In this paper, considering
the Rashba effect on semiconductor region, we have discussed the spin transfer
torque in semiconductor/ferromagnetic structure and obtained the components of
spin-current density for two models: (I)-single electron and (II)- the
distribution of electrons. We have shown that whatever the difference between
Fermi surfaces in semiconductor and Fermi spheres for the up and down spins in
ferromagnetic increase, the transmission probability decreases. The obtained
results for the values used in this article illustrate that Rashba effect
increases the difference between a Fermi sphere in semiconductors and Fermi
sphere for the up and down spins in ferromagnetic. The results also show that
the Rashba effect, brings an additional contribution to the components of spin
transfer torque, which is not exist in the absence of the Rashba interaction.
Moreover, the Rashba term has also different effects on the transverse
components of the spin torque transfer.
