  We show that a quantum wire device with spin splitting can work as an active
spin polarizer. Hot electrons in one `spin' subband (e.g. `spin-up') may pass
such a device with weak electron pair scattering, while electrons in the
opposite subband (`spin-down') may have high conversion probability into the
`spin-up' subband, resulting in spin polarization of a hot electron beam. Under
different circumstances a hot electron beam passing through a single mode
quantum wire may induce a steady state magnetization of the background electron
gas in a section of the wire weakly coupled to the environment.
