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arXiv · 0912.0205

Observation of spin-triplet superconductivity in Co-based Josephson Junctions

Trupti S. Khaire·Mazin A. Khasawneh·W. P. Pratt, Jr.·Norman O. Birge
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Abstract

We have measured a long-range supercurrent in Josephson junctions containing Co (a strong ferromagnetic material) when we insert thin layers of either PdNi or CuNi weakly-ferromagnetic alloys between the Co and the two superconducting Nb electrodes. The critical current in such junctions hardly decays for Co thicknesses in the range of 12-28 nm, whereas it decays very steeply in similar junctions without the alloy layers. The long-range supercurrent is controllable by the thickness of the alloy layer, reaching a maximum for a thickness of a few nm. These experimental observations provide strong evidence for induced spin-triplet pair correlations, which have been predicted to occur in superconducting/ferromagnetic hybrid systems in the presence of certain types of magnetic inhomogeneity.

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Trupti S. Khaire, Mazin A. Khasawneh, W. P. Pratt, Jr., Norman O. Birge. 2009-12-01. Observation of spin-triplet superconductivity in Co-based Josephson Junctions. https://doi.org/10.1103/physrevlett.104.137002

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