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".