Thermally Driven Inhibition of Superconducting Vortex Avalanches

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.