Electrodynamics of Josephson junctions containing strong ferromagnets

TL;DR

This study provides a detailed electrodynamic analysis of multilayer ferromagnetic Josephson junctions with triplet supercurrents, revealing unique phase dynamics that could advance superconducting spintronics.

Contribution

It offers the first comprehensive experimental characterization of the phase dynamics in triplet supercurrent Josephson junctions with strong ferromagnets.

Findings

Triplet supercurrents penetrate thicker ferromagnetic barriers.

Junctions exhibit long, moderately damped phase dynamics.

Unconventional behavior suggests new detection methods for triplet supercurrents.

Abstract

Triplet supercurrents in multilayer ferromagnetic Josephson junctions with misaligned magnetization can penetrate thicker ferromagnetic barriers compared to the singlet component. Although the static properties of these junctions have been extensively studied, the dynamic characteristics remain largely unexplored. Here we report a comprehensive electrodynamic characterization of multilayer ferromagnetic Josephson junctions composed of Co and Ho. By measuring the temperature-dependent current-voltage characteristics and the switching current distributions down to 0.3 K, we show that phase dynamics of junctions with triplet supercurrents exhibits long (in terms of proximity) junction behavior and moderately damped dynamics with renormalized capacitance and resistance. This unconventional behavior possibly provides a different way to dynamically detect triplets. Our results show new theoretical models are required to fully understand the phase dynamics of triplet Josephson junctions for applications in superconducting spintronics.