Description:
The construction of a spinguide—a semiconductor channel with walls consisting of a dilute magnetic semiconductor with very large Zeeman splitting and transmitting electrons only with one type of polarization—is proposed. Such channels can be sources of spin-polarized current in nonmagnetic conductors. They can be used for creating fast switches of the spin-polarization direction of the electric current and for transmitting spin polarization over large distances (even larger than the spin-flip length). The selective transparency of the walls gives rise to new size transport effects.