2015/06/16 by N. Banerjee, J. W. A. Robinson, M. G. Blamire
Physics and Astronomy · #cond-mat.supr-con
paper · pdf · doi:10.1038/ncomms5771
published as Nature Communications, 5:4771 (2014) · 17 pages, 3 figures
arxiv created 2015/06/16 · arxiv updated 2015/06/17
Magnetic inhomogeneity at a superconductor (S)/ferromagnet (F) interface converts spin-singlet Cooper pairs into spin-one triplet pairs. These pairs are immune to the pair-breaking exchange field in F and support a long-range proximity effect. Although recent experiments have confirmed the existence of spin-polarised triplet supercurrents in S-F-S Josephson junctions, reversible control of the supercurrent has been impossible because of the robust pre-configured nature of the inhomogeneity. Here we use a barrier comprising three F layers whose relative magnetic orientation, and hence the interfacial inhomogeneity, can be controlled by small magnetic fields; we show that this enables full control of the triplet supercurrent and, by using finite element micromagnetic simulations, we can directly relate the experimental data to the theoretical models which provide a general framework to understand the role played by magnetic states in long-range supercurrent modulation.