Low volume fraction of high-Tc superconductivity in La3Ni2O7 at 80 K and ambient pressure

TL;DR

This study reports the observation of a very small volume fraction of high-temperature superconductivity at 80 K in La3Ni2O7 under ambient pressure, highlighting factors influencing its emergence and suggesting avenues for further research.

Contribution

It demonstrates the presence of high-temperature superconductivity in La3Ni2O7 at ambient pressure with a practical approach for future investigations.

Findings

Superconductivity observed at 80 K in La3Ni2O7 at ambient pressure

Superconducting volume fraction estimated at 0.2%

Resistivity decreases indicating superconducting behavior

Abstract

The discovery of superconductivity in pressurized La3Ni2O7 with a transition temperature of approximately 80 K above the boiling point of liquid nitrogen has sparked significant attention. It is essential to search for high-temperature superconductivity in bulk samples and at ambient pressure in nickelates. In this study, we report influential factors that affect the appearance of superconductivity in La3Ni2O7 at ambient pressure. From direct-current magnetic measurements, we observe a clear diamagnetic response at 80 K in post-annealed single crystals of La3Ni2O7 in oxygen. The superconducting volume fraction is estimated to be within 0.2%, resulting in a decrease in resistivity. This work presents a practical approach for further investigating high-temperature superconductivity in nickelates at ambient pressure.