Enhancement of Critical Current across Single Grain Boundaries in YBa2Cu3Ox and Search for Superconductivity in Alkali Metals

TL;DR

This paper reports that hydrostatic pressure enhances current-carrying capacity across grain boundaries in YBa2Cu3Ox and explores superconductivity in alkali metals, finding Li becomes superconducting at high pressure, but Na and K do not.

Contribution

It demonstrates pressure-induced enhancement of grain boundary current in YBa2Cu3Ox and investigates superconductivity in alkali metals under high pressure, revealing Li's superconductivity at high pressure.

Findings

Hydrostatic pressure significantly improves current flow in YBa2Cu3Ox grain boundaries.

Li becomes superconducting above 20 GPa at temperatures up to 15 K.

Na and K do not exhibit superconductivity up to the tested pressures and temperatures.

Abstract

The ability of single grain boundaries in YBa2Cu3Ox bicrystalline rings to carry electrical current is found to be significantly enhanced under hydrostatic pressure. Nearly hydrostatic pressures are applied to the alkali metals Li, Na, and K. in a search for superconductivity. Whereas Li becomes superconducting above 20 GPa at temperatures as high as 15 K, no superconductivity was observed above 4 K in Na to 65 GPa nor in K above 4 K to 43.5 GPa or above 1.5 K to 35 GPa.