First observation of flux avalanches in a-MoSi superconducting thin films

TL;DR

This paper reports the first observation of dendritic flux avalanches in amorphous MoSi superconducting thin films, highlighting their thermomagnetic origin and implications for applications.

Contribution

It provides the first experimental evidence of flux avalanches in amorphous MoSi films, expanding the understanding of flux behavior in superconducting thin films.

Findings

Flux avalanches are thermomagnetic in origin.

Avalanches occur within specific temperature and magnetic field ranges.

MoSi films exhibit flux avalanches similar to other superconductors.

Abstract

We have observed the occurrence of dendritic flux avalanches in an amorphous film of Mo$_{84}$Si$_{16}$. These events are understood to have a thermomagnetic origin and involve the abrupt penetration of bursts of magnetic flux taking place within a limited window of temperatures and magnetic fields. While dc-magnetometry allows one to determine the threshold fields for the occurrence of the thermomagnetic instabilities, magneto-optical imaging reveals the spatial distribution of magnetic flux throughout the sample. Conducting appropriate experiments, typical for this goal, avalanches were confirmed to be a characteristic of this material, ruling out the otherwise admissible possibility of an experimental artifact or a feature related to defects in the film. After the present observation, a-MoSi can be included in the gallery of superconducting materials exhibiting flux avalanches when in the form of thin films, a characteristic that must be carefully taken into consideration when one plans to employ films of those materials in applications.