Second-Harmonic Current-Phase Relation in Josephson Junctions with Ferromagnetic Barriers
Second-Harmonic Current-Phase Relation in Josephson Junctions with Ferromagnetic Barriers
We report the observation of a current-phase relation dominated by the second Josephson harmonic in superconductor-ferromagnet-superconductor junctions. The exotic current-phase relation is realized in the vicinity of a temperature-controlled 0-to-$\pi$ junction transition, at which the first Josephson harmonic vanishes. Direct current-phase relation measurements, as well as Josephson interferometry, non-vanishing supercurrent …