Coexistence of Diamagnetism and Vanishingly Small Electrical Resistance at Ambient Temperature and Pressure in Nanostructures

TL;DR

This study reports nanostructured silver-gold composites exhibiting near-zero electrical resistance and strong diamagnetism at ambient conditions, with potential to tune the critical temperature well above room temperature.

Contribution

It demonstrates the coexistence of diamagnetism and vanishing resistance in nanostructures at ambient temperature and pressure, and introduces methods to increase the critical temperature.

Findings

Resistance drops below 2 microohms below 286 K

Resistivity is at least four orders of magnitude lower than noble metals

Samples exhibit strong diamagnetism with susceptibilities as low as -0.056

Abstract

The great practical utility has motivated extensive efforts to discover ultra-low resistance electrical conductors and superconductors in ambience. Here we report the observation of vanishingly small electrical resistance at the ambient temperature and pressure conditions in films and pellets of a nanostructured material that is composed of silver particles embedded into a gold matrix. Upon cooling below a sample-specific temperature scale ($T_{C}$) as high as $286$ K, the film resistance drops below $\sim 2\mu\Omega$, being limited by measurement uncertainty. The corresponding resistivity ($\sim 10^{-12}$ $\Omega$.m) is at least four orders of magnitude below that of elemental noble metals, such as gold, silver or copper. Furthermore, the samples become strongly diamagnetic below $T_{C}$, with volume susceptibilities as low as -0.056. We additionally describe methods to tune $T_{C}$ to temperatures much higher than room temperature.