Thermally driven inhibition of superconducting vortex avalanches

TL;DR

This study reveals that microwave stimulation can inhibit vortex avalanches in type II superconductors near critical conditions, with the effect strongly dependent on excitation frequency and vortex core nonlinearities.

Contribution

It demonstrates the frequency-dependent inhibition of vortex avalanches via microwave stimulation and proposes a nonlinear vortex core model to explain this behavior.

Findings

Avalanches are suppressed near depinning frequencies.

Inhibition increases approaching critical temperature or magnetic field.

A nonlinear vortex core size model explains the observed phenomena.

Abstract

Complex systems close to their critical state can exhibit abrupt transitions, avalanches, between their metastable states. It is a challenging task to understand the mechanism of the avalanches and control their behavior. Here we investigate microwave (mw) stimulation of avalanches in the so- called vortex matter of type II superconductors, a system of interacting Abrikosov vortices close to the critical (Bean) state. Our main finding is that the avalanche incubation strongly depends on the excitation frequency, a completely unexpected behavior observed close to the so-called depinning frequencies. Namely, the triggered vortex avalanches in Pb superconducting films become effectively inhibited approaching the critical temperature or critical magnetic field when the mw stimulus is close to the vortex depinning frequency. We suggest a simple model explaining the observed counter- intuitive behaviors as a manifestation of the strongly nonlinear dependence of the driven vortex core size on the mw excitation intensity. This paves the way to controlling avalanches in complex systems through their nonlinear response.