  We study the critical current of a S/F-I-N/S tunnel structure - a proximity
coupled superconductor (S) with thin ferromagnetic (F) and nonmagnetic (N)
metals separated by an insulating (I) barrier - in an external magnetic field.
The dependence of the current on exchange and external magnetic fields, and
their mutual orientation is analyzed within the microscopic theory of the
proximity effect. We find that the S/F-I-N/S contact with strong magnetism of
the F layer is in a ground state with superconducting phase difference on the
electrodes about pi/2. Low external magnetic field reverses the critical
current sign of such a contact (a \pi-state of the junction) for parallel field
orientation. For antiparallel alignment the dc Josephson current behavior is
essentially nonmonotonic: by increasing an external magnetic field the current
passes though a maximum, while the 0-phase state is held, and then the junction
gets into the \pi-phase state with an opposite current direction. We
demonstrate that the hybrid S/F-I-N/S metal structures possess new effects of
the superconductivity in the presence of spin splitting, while an experimental
set-up seems to be feasible and it may lead to further understanding of
superconducting proximity effects in ferromagnetic materials.
