Velocimetry of superconducting vortices based on stroboscopic resonances

An experimental determination of the mean vortex velocity in superconductors mostly
relies on the measurement of flux-flow resistance with magnetic field, temperature, or driving
current. In the present work we introduce a method combining conventional transport
measurements and a frequency-tuned flashing pinning potential to obtain reliable estimates
of the vortex velocity. The proposed device is characterized using the time-dependent
Ginzburg-Landau formalism, where the velocimetry method exploits the resonances in mean
vortex dissipation when temporal commensuration occurs between the vortex crossings and
the flashing potential. We discuss the sensitivity of the proposed technique on applied current,
temperature and heat diffusion, as well as the vortex core deformations during fast
motion.