Spin transmission in a series of magnetic barrier structure

The spin transport properties in the model of a series of δ-function magnetic barriers are studied on the basis of Lippmann-Schwinger equation. We find that if the magnetic fields are equal in magnitude, the polarization of the outgoing electron beam depends on the relative orientations of magnetic barriers. In addition to the unpolarized configuration in an antiparallel magnetic barrier structure, we find other unpolarized configurations in canted magnetic fields that manifest different properties. The relations of the angles, the magnetic field direction with z-axis, are given in unpolarized configurations. The deviation of the magnetic field direction from the unpolarized angle results in a sign change of polarization in the canted unpolarized configuration, which may provide a realization of spin valve device.