  A novel state is predicted for a S/F heterostructure. It is shown that the
equilibrium F/S bilayer can be in a bistable state: one state is ground and the
other is metastable. One of these states is always normal and the other is
superconducting. One can switch between these states by an external control
parameter, for example, by an applied magnetic field. This phenomenon can
manifest itself through the hysteresis behavior upon varying the applied
magnetic field or, even, temperature. It can also lead to transition of the
heterostructure into the superconducting state upon increase of the
temperature.
