Exceptional type-I superconductivity of the layered silver oxide Ag$_5$Pb$_2$O$_6$

TL;DR

This paper presents evidence that layered silver oxide Ag$_5$Pb$_2$O$_6$ exhibits type-I superconductivity, characterized by magnetic and resistivity measurements, making it potentially the first oxide with such properties.

Contribution

It reports the discovery of type-I superconductivity in Ag$_5$Pb$_2$O$_6$, a layered silver oxide, supported by magnetic and resistivity data, and analyzes its superconducting parameters.

Findings

Ag$_5$Pb$_2$O$_6$ shows zero-resistivity transition.

Magnetic susceptibility indicates type-I superconductivity.

Superconductivity is in the dirty limit.

Abstract

We report zero-resistivity transition and the details of magnetic transition of a layered silver oxide Ag$_5$Pb$_2$O$_6$ single crystal, which make definitive evidence of superconductivity in this compound. In the AC susceptibility of a mono-crystal, we observed large supercooling, as well as positive peaks in the real part of the susceptibility indicating the reversibility of magnetic process. These observations reveal that Ag$_5$Pb$_2$O$_6$ is probably the first oxide that shows type-I superconductivity. Evaluation of the superconducting parameters not only gives confirming evidence of type-I superconductivity, but also indicates that it is a dirty-limit superconductor. We also analyze supercooling to determine the upper limit of the Ginzburg-Landau parameter.