STSM of Stanislava Shpilinska (University of Vienna, Austria) at the Goethe University (Germany): Nanoengineered superconductors for high-velocity vortex dynamics

The aim of this short-term scientific mission (STSM) was to characterize superconductor-based hybrid structures with foci on their current-carrying capability and ultimate vortex velocities.

Electrical transport measurements were done in 4He flow cryostat with magnetic field oriented perpendicular to the films surface. The analysis of current-voltage curves revealed that the maximal vortex velocities are an order of magnitude larger for superconductor/normal metal bilayers compared to single superconducting layers.

The enhancement of the critical current and the vortex instability velocity is attributed to the combined effects of the highly conducting Au layers: effective heat removal from the superconductor (suppression of Joule heating) as well as enhancement of the superconducting coherence length, reduction of penetration depth and, consequently, reduction of the background pinning due to the expansion of the vortex cores.