Vortex transport and voltage noise in disordered superconductors

TL;DR

This paper investigates vortex transport and voltage noise in disordered superconductors using 3D Monte Carlo simulations, revealing universal noise behavior near depinning and defect-dependent spectral features at higher currents.

Contribution

It provides new insights into the voltage noise spectrum and vortex dynamics in superconductors with different types of pinning centers, highlighting universal and defect-specific behaviors.

Findings

Voltage noise spectrum follows a 1/w^a power law near depinning.

Distinct peaks in noise spectrum appear for currents above depinning threshold.

Extended defects produce more pronounced spectral features than point defects.

Abstract

We study, by means of three-dimensional Monte Carlo simulations, the current-voltage (IV) characteristics and the voltage noise spectrum at low temperatures of driven magnetic flux lines interacting with randomly placed point or columnar defects, as well as with periodically arranged linear pinning centers. Near the depinning current J_c, the voltage noise spectrum S(w) universally follows a 1/w^a power law. For currents J > J_c, distinct peaks appear in S(w) which are considerably more pronounced for extended as compared to point defects, and reflect the spatial distribution of the correlated pinning centers.