The recently developed semiclassical theory for magnetoelectronic circuits
is applied to a transistor-like device consisting of a normal metal island
and three magnetic terminals. The electric current between source and drain
can be controlled by the magnetization of the base reservoirs up to distan
ces of the order of the spin-flip diffusion length. (C) 2001 Elsevier Scien
ce B.V. All rights reserved.