Superconducting phase coherent electron transport in proximity conical ferromagnets

TL;DR

This paper demonstrates superconducting phase-coherent electron transport in Ho conical ferromagnets, revealing long-range triplet superconductivity due to the unique magnetic structure, with observable conductance oscillations over large distances.

Contribution

It provides experimental evidence of long-range triplet superconductivity in conical ferromagnets, advancing understanding of superconductor-ferromagnet hybrid systems.

Findings

Observation of phase-periodic conductance oscillations in Ho wires.

Identification of long-range triplet component of the superconducting order parameter.

Oscillations explained by the helical triplet component induced at interfaces.

Abstract

We report superconducting phase-periodic conductance oscillations in ferromagnetic wires with interfaces to conventional superconductors. The ferromagnetic wires were made of Ho, a conical ferromagnet. The distance between the interfaces was much larger than the singlet superconducting penetration depth. We explain the observed oscillations as due to the long-range penetration of an unusual "helical" triplet component of the order parameter that is generated at the superconductor/ferromagnet interfaces and maintained by the intrinsic rotating magnetization of Ho.