Josephson effect in a $CeCoIn_5$ microbridge

TL;DR

This study demonstrates the presence of DC Josephson effects in a CeCoIn_5 microbridge, revealing unique magnetic and temperature-dependent behaviors that challenge conventional microbridge models.

Contribution

First observation of Josephson effects in a CeCoIn_5 microbridge, with unexpected I_c(T) behavior following the Ambegaokar-Baratoff relation.

Findings

Periodic voltage modulations under magnetic field consistent with Josephson effects

Asymmetric magnetic field dependence of voltage modulations

Temperature dependence of critical current follows Ambegaokar-Baratoff relation

Abstract

We report DC Josephson effects observed in a microbridge prepared from an individual crystalline growth domain of $CeCoIn_5$ thin film. Josephson effects were observed by periodic voltage modulations under external magnetic field $\Delta V(B)$ with the expected periodicity and by the temperature dependence of the Josephson critical current $I_c(T)$. The shape of $\Delta V(B)$ was found to be asymmetric, as it is expected for microbridges. The dependence $I_c(T)$ follows the Ambegaokar-Baratoff relation, which is unexpected for microbridges. Features in the dynamical resistance curves were attributed to the periodic motion of Abricosov vortices within the microbridge.