Observation of coherent Josephson response in the non-linear ab-plane microwave impedance of $YBa_{2}Cu_{3}O_{6.95}$ single crystals

TL;DR

This paper reports the observation of coherent Josephson effects in the non-linear microwave impedance of YBa2Cu3O6.95 single crystals, indicating intrinsic Josephson behavior in the ab-plane at microwave frequencies.

Contribution

It demonstrates that the entire crystal behaves like a single Josephson junction, revealing intrinsic non-linear Josephson phenomena in high-temperature superconductor crystals.

Findings

Microwave impedance exhibits non-linear behavior described by the RSJ model.

The crystal acts as a single Josephson junction.

Data suggests an intrinsic Josephson mechanism.

Abstract

We report novel non-linear phenomena in the $ab$-plane microwave impedance of $YBaCu_{2}O_{7-\delta }$ single crystals. The $R_s$ vs. $H_{rf}$ data are well described by the non-linear RSJ model : $\dot{\phi}+\sin \phi =i_{rf}\cos \omega t$. The entire crystal behaves like a single Josephson junction. The extraordinary coherence of the data suggests an intrinsic mechanism.