Moisture-induced superconductivity in FeTe0.8S0.2

TL;DR

This study demonstrates that exposure to moisture, especially hot water, induces and enhances superconductivity in FeTe0.8S0.2, transforming it from filamentary to bulk superconductivity with higher transition temperature and volume fraction.

Contribution

It reveals that moisture exposure, particularly hot water immersion, can induce and significantly enhance superconductivity in FeTe0.8S0.2, a novel finding for this material.

Findings

Superconductivity improved with air exposure, reaching 7.2 K and 48.5% volume fraction.

Water-related ions/molecules are responsible for inducing superconductivity.

Hot water immersion accelerates the evolution of superconductivity.

Abstract

Moisture-induced superconductivity was observed in FeTe0.8S0.2. With exposing the sample to the air, the zero resistivity temperature and the superconducting volume fraction were enhanced up to 7.2 K and 48.5 %, respectively, while the as-grown sample showed only filamentary superconductivity. We concluded that the causes of the evolution of superconductivity were water-related ions and/or molecules, because only the sample kept in water at room temperature for several days showed superconductivity. The speed of evolution of superconductivity was strongly enhanced by immersing the sample into the hot water.