Observation of Josephson coupling through an interlayer of antiferromagnetically ordered chromium

TL;DR

This study demonstrates Josephson supercurrent transport through chromium, an itinerant antiferromagnet, revealing its dependence on layer thickness and providing estimates for its coherence length and diffusion constant.

Contribution

It provides the first experimental observation of Josephson coupling through an antiferromagnetic chromium interlayer and compares results with theoretical models.

Findings

Supercurrent observed through chromium interlayer

Weak dependence of supercurrent on thin chromium layers

Exponential decay of supercurrent with thicker films

Abstract

The supercurrent transport in metallic Josephson tunnel junctions with an additional interlayer made up by chromium, being an itinerant antiferromagnet, was studied. Uniform Josephson coupling was observed as a function of the magnetic field. The supercurrent shows a weak dependence on the interlayer thickness for thin chromium layers and decays exponentially for thicker films. The diffusion constant and the coherence length in the antiferromagnet were estimated. The antiferromagnetic state of the barrier was indirectly verified using reference samples. Our results are compared to macroscopic and microscopic models.