Avalanches and Self-Organized Criticality in Superconductors

TL;DR

This paper reviews how superconductors serve as a platform for studying avalanche phenomena and self-organized criticality, combining experimental magneto-optical observations with analytical modeling to understand vortex dynamics.

Contribution

It introduces a comprehensive experimental and theoretical framework linking vortex landscape roughening to avalanche behavior in superconductors, highlighting the effects of anisotropy and thermo-magnetic instabilities.

Findings

Vortex density distribution monitored over time reveals self-organized criticality.

Analytical models align closely with experimental avalanche data.

Anisotropic substrates suppress avalanche size and frequency.

Abstract

We review the use of superconductors as a playground for the experimental study of front roughening and avalanches. Using the magneto-optical technique, the spatial distribution of the vortex density in the sample is monitored as a function of time. The roughness and growth exponents corresponding to the vortex landscape are determined and compared to the exponents that characterize the avalanches in the framework of Self-Organized Criticality. For those situations where a thermo-magnetic instability arises, an analytical non-linear and non-local model is discussed, which is found to be consistent to great detail with the experimental results. On anisotropic substrates, the anisotropy regularizes the avalanches.