Triplet supercurrent due to spin-active zones in a Josephson junction

TL;DR

This paper presents a theoretical model explaining triplet supercurrent in a ferromagnetic Josephson junction, emphasizing the role of spin-active zones with canted magnetic moments, aligning well with recent experimental findings.

Contribution

The model introduces spin-active zones with canted magnetic moments as a key mechanism for triplet supercurrent, providing a theoretical framework consistent with experiments.

Findings

Qualitative agreement with experimental supercurrent data

Identification of spin-active zones as essential for triplet pairing

Discussion of experimental implications of spin-active interfaces

Abstract

Motivated by a recent experiment evidencing triplet superconductivity in a ferromagnetic Josephson junction with a Cu$_2$MnAl-Heusler barrier, we construct a theoretical model accounting for this observation. The key ingredients in our model which generate the triplet supercurrent are \textit{spin-active zones}, characterised by an effective canted interface magnetic moment. Using a numerical solution of the quasiclassical equations of superconductivity with spin-active boundary conditions, we find qualitatively very good agreement with the experimentally observed supercurrent. Further experimental implications of the spin-active zones are discussed.