Abstract
We report measurements of the temperature dependence of the critical current, , in Josephson junctions consisting of conventional superconducting banks of Nb and a weakly ferromagnetic interlayer of a alloy, with around 0.5. With decreasing temperature generally increases, but for specific thicknesses of the ferromagnetic interlayer, a maximum is found followed by a strong decrease down to zero, after which 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 phase state at low temperatures.
- Received 24 August 2000
DOI:https://doi.org/10.1103/PhysRevLett.86.2427
©2001 American Physical Society