Observation of Magnetic Fingerprints in Superconducting Au_0.7In_0.3 Cylinders

TL;DR

This study reports the experimental observation of reproducible, sample-specific magnetic fingerprints in disordered superconducting Au_0.7In_0.3 cylinders, revealing significant mesoscopic fluctuations in the superconducting transition regime.

Contribution

It provides the first experimental evidence of magnetic fingerprints in superconducting cylinders and discusses their origin in mesoscopic fluctuations of the condensation energy.

Findings

Magnetoresistance fluctuations are reproducible and sample-specific.

Fluctuation amplitude exceeds universal conductance fluctuations in normal metals.

Physical origin linked to mesoscopic fluctuations of superconducting condensation energy.

Abstract

Reproducible, sample-specific magnetoresistance fluctuations (magnetic fingerprints) have been observed experimentally in the low-temperature part of the superconducting transition regime of disordered superconducting Au_0.7In_0.3 cylinders. The amplitude of the fluctuation was found to exceed that of the universal conductance fluctuation in normal metals by several orders of magnitude. The physical origin of these observations is discussed in the context of mesoscopic fluctuations of the superconducting condensation energy in disordered superconductors.