pi-0 transition in superconductor-ferromagnet-superconductor junctions

Superconductor-ferromagnet-superconductor (SFS) Josephson junctions are kno wn to exhibit a transition between pi and 0 states. In this letter, we find the pi -0 phase diagram of an SFS junction depending on the transparency o f an intermediate insulating layer (I). We show that, in general, the Josep hson critical current is nonzero at the pi -0 transition temperature. Contr ibutions to the current from the two spin channels nearly compensate each o ther, and the first harmonic of the Josephson current as a function of phas e difference is suppressed. However, higher harmonics give a nonzero contri bution to the supercurrent. (C) 2001 MAIK "Nauka / Interperiodica".