Controlled Injection of Spin-Triplet Supercurrents into a Strong Ferromagnet

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Science  10 Jun 2010:
DOI: 10.1126/science.1189246


The superconductor-ferromagnet proximity effect describes the fast decay of a spin-singlet supercurrent originating from the superconductor upon entering the neighboring ferromagnet. After placing a conical magnet (Ho) at the interface between the two, we detect a long-ranged supercurrent in the ferromagnetic layer. The long-range effect requires particular thicknesses of the spiral-magnetically-ordered Ho, consistent with spin-triplet proximity theory. This enables control of the electron pairing symmetry by tuning the degree of magnetic inhomogeneity through the thicknesses of the Ho injectors.