Controllable generation of a spin-triplet supercurrent in a Josephson spin-valve

TL;DR

This paper experimentally demonstrates that the supercurrent in a Josephson spin-valve can be controlled by the relative magnetization orientation of ferromagnetic layers, confirming the generation of spin-triplet superconductivity.

Contribution

It provides the first experimental evidence of controllable spin-triplet supercurrent in a nano-scale Josephson spin-valve device.

Findings

Supercurrent depends on ferromagnetic layer orientation.

Supercurrent is enhanced in non-collinear magnetic states.

Direct proof of controllable spin-triplet generation.

Abstract

It has been predicted theoretically that an unconventional odd-frequency spin-triplet component of superconducting order parameter can be induced in multilayered ferromagnetic structures with non-collinear magnetization. In this work we study experimentally nano-scale devices, in which a ferromagnetic spin valve is embedded into a Josephson junction. We demonstrate two ways of in-situ analysis of such Josephson spin valves: via magnetoresistance measurements and via in-situ magnetometry based on flux quantization in the junction. We observe that supercurrent through the device depends on the relative orientation of magnetization of the two ferromagnetic layers and is enhanced in the non-collinear state of the spin valve. This provides a direct prove of controllable generation of the spin-triplet superconducting component in a ferromagnet.