  The current driven magnetization dynamics of a thin-film, three magnetic
terminal device (spin-flip transistor) is investigated theoretically. We
consider a magnetization configuration in which all magnetizations are in the
device plane, with source-drain magnetizations chosen fixed and antiparallel,
whereas the third contact magnetization is allowed to move in a weak anisotropy
field that guarantees thermal stability of the equilibrium structure at room
temperature. We analyze the magnetization dynamics of the free layer under a dc
source-drain bias current within the macrospin model and magneto-electronic
circuit theory. A new tunable two-state behavior of the magnetization is found
and the advantages of this phenomenon and potential applications are discussed.
