π - 0 Transition in Superconductor-Ferromagnet Junctions

We find the π-0 phase diagram of an SFS junction depending on the transparency of an intermediate insulating layer (I). We show that in general, the Josephson critical current is nonzero at the π - 0 transition temperature. The currents in the two spin channels nearly compensate each other and the first harmonic of the Josephson current as a function of phase difference is suppressed. However, higher harmonics give a nonzero contribution to the supercurrent.