Abstract
We observe an unconventional superconducting minigap induced into a ferromagnet from a spin-triplet superconductor using an tunnel junction. Voltage bias differential conductance of the tunnel junctions exhibits V-shaped gap features around zero bias, corresponding to a decrease in the density of states with an opening of a superconducting minigap in . Observation of a minigap at the surface of a 15-nm-thick layer confirms the spin-triplet nature of induced superconductivity. The shape and temperature dependence of the gap features in the differential conductance suggest that the even-frequency -wave correlations dominate over odd-frequency -wave correlations. Theoretical calculations support this -wave scenario. Our work provides the density-of-states proof for an induced minigap in a ferromagnet, and it significantly advanced our understanding of the spin-triplet proximity effect between unconventional superconductors and ferromagnets.
- Received 3 March 2019
- Revised 18 June 2019
DOI:https://doi.org/10.1103/PhysRevB.100.024516
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