title: Coupling of two superconductors through a ferromagnet: evidence for a pi junction.
abstract: We report measurements of the temperature dependence of the critical current, I(c), in Josephson junctions consisting of conventional superconducting banks of Nb and a weakly ferromagnetic interlayer of a CuxNi1-x alloy, with x around 0.5. With decreasing temperature I(c) generally increases, but for specific thicknesses of the ferromagnetic interlayer, a maximum is found followed by a strong decrease down to zero, after which I(c) rises again. Such a sharp cusp can be explained only by assuming that the junction changes from a 0-phase state at high temperatures to a pi phase state at low temperatures.
authors: Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka.
authors: V V
authors: VV
authors: Ryazanov
authors: V A
authors: VA
authors: Oboznov
authors: A Y
authors: AY
authors: Rusanov
authors: A V
authors: AV
authors: Veretennikov
authors: A A
authors: AA
authors: Golubov
authors: J
authors: J
authors: Aarts