Measurement of the current-phase relation of superconductor/ferromagnet/superconductor π Josephson junctions -: art. no. 144505

We present measurements of the current-phase relation (CPR) of superconductor-ferromagnet-superconductor (SFS) Josephson junctions as a function of temperature. The CPR is determined by incorporating the junction into a superconducting loop coupled to a dc SQUID, allowing measurement of the junction phase difference. We find that the critical current of Nb-Cu0.47Ni0.53-Nb Josephson junctions with barrier thickness similar to22 nm changes sign at T