Vortex avalanches and self organized criticality in superconducting niobium

TL;DR

This paper provides experimental evidence that vortex avalanches in superconducting niobium exhibit self-organized criticality, demonstrated by power-law scaling of avalanche sizes across various magnetic conditions.

Contribution

It offers the first conclusive experimental validation that vortex dynamics in superconductors follow self-organized criticality, using extensive micro-Hall probe data and magneto-optical imaging.

Findings

Power-law distribution of vortex avalanche sizes over two decades

Scaling behavior remains consistent across different magnetic landscapes

Confirms vortex avalanches as a SOC phenomenon in superconductors

Abstract

In 1993 Tang proposed [1] that vortex avalanches should produce a self organized critical state in superconductors, but conclusive evidence for this has heretofore been lacking. In the present paper, we report extensive micro-Hall probe data from the vortex dynamics in superconducting niobium, where a broad distribution of avalanche sizes scaling as a power-law for more than two decades is found. The measurements are combined with magneto-optical imaging, and show that over a widely varying magnetic landscape the scaling behaviour does not change, hence establishing that the dynamics of superconducting vortices is a SOC phenomenon.