  The conditions for the occurrence of pronounced magnetoelectric bistabilities
in the resonant tunneling through a ferromagnetic quantum well are
theoretically investigated. The bistability appears due to the mutual feedback
of the carriers Coulomb interaction and the carriers exchange coupling with
magnetic impurities in the well. It is shown that the well Curie temperature
depends strongly on the relative alignment of the quantum well level and the
reservoirs chemical potentials, which can be modified electrically. Switching
between a "current-on/magnetism-off" and a "current-off/magnetism-on" mode
becomes possible, if the well temperature lies in-between the bistable values
of the well Curie temperature.
