  We investigate the spin-dependent transport properties of two-dimensional
electron gas (2DEG) systems formed in diluted magnetic semiconductors and in
the presence of Rashba spin-orbit interaction in the framework of the
scattering matrix approach. We focus on nanostructures consisting of realistic
magnetic barriers produced by the deposition of ferromagnetic strips on
heterostructures. We calculate spin-dependente conductance of such barrier
systems and show that the magnetization pattern of the strips, the tunable
spin-orbit coupling, and the enhanced Zeeman splitting have a strong effect on
the conductance of the structure. We describe how these effects can be employed
in the efficient control of spin polarization via the application of moderate
fields.
