Josephson junctions with s-wave superconductors (S) and multiple ferromagnetic (F) layers carry spin-triplet supercurrents in the presence of magnetically inhomogeneous spin-mixer interfaces. Here, we report magnetic Josephson junctions with exchange-spring and double exchange-spring ("spin-mixer") Co/Py interfaces. At the Co/Py interface, exchange coupling is strong with respect to the magnetic anisotropy of Py and so, depending on the direction and magnitude of an external magnetic field, a non-collinear magnetic structure forms in Py creating the necessary magnetic inhomogeneity for singlet-to-triplet pair conversion. We detect supercurrents through Py with a thickness exceeding 10 nm, which is much larger than the singlet pair coherence length, suggesting the propagation of magnetically tuneable triplet supercurrents.
@article{arxiv.1907.08406,
title = {Magnetic-field-orientation-dependent triplet supercurrents in Josephson junctions with symmetric and asymmetric exchange-spring interfaces},
author = {Ekta Bhatia and J. M. Devine-Stoneman and S. Komori and A. Srivastava and N. A. Stelmashenko and Z. H. Barber and K. Senapati and J. W. A. Robinson},
journal= {arXiv preprint arXiv:1907.08406},
year = {2019}
}