π-junction realization due to tunneling through a thin ferromagnetic layer

It is demonstrated that in superconductor-ferromagnet-superconductor (S/F/S) systems in the case of low interface transparency the transition into π-phase is not related with the oscillations of the superconducting order parameter in F-layer. Consequently, the π-phase may exist at very thin F-layer thickness. The crossover from π-to 0-phase results in the nonmonotonous temperature dependence of the critical current.