  A magnetoelectronic thin-film transistor is proposed that can display
negative differential resistance and gain. The working principle is the
modulation of the soure-drain current in a spin valve by the magnetization of a
third electrode, which is rotated by the spin-torque created by a control
spin-valve. The device can operate at room temperature, but in order to be
useful, ferromagnetic materials with polarizations close to unity are required.
