Second-harmonic current-phase relation in Josephson junctions with ferromagnetic barriers
Abstract
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- junction transition, at which the first Josephson harmonic vanishes. Direct current-phase relation measurements, as well as Josephson interferometry, non-vanishing supercurrent and half-integer Shapiro steps at the 0- transition self-consistently point to an intrinsic second harmonic term, making it possible to rule out common alternative origins of half-periodic behavior. While surprising for diffusive multimode junctions, the large second harmonic is in agreement with theory predictions for thin ferromagnetic interlayers.
Cite
@article{arxiv.1805.12546,
title = {Second-harmonic current-phase relation in Josephson junctions with ferromagnetic barriers},
author = {M. J. A. Stoutimore and A. N. Rossolenko and V. V. Bolginov and V. A. Oboznov and A. Y. Rusanov and D. S. Baranov and N. Pugach and S. M. Frolov and V. V. Ryazanov and D. J. Van Harlingen},
journal= {arXiv preprint arXiv:1805.12546},
year = {2018}
}