Velocimetry of superconducting vortices based on stroboscopic resonances

Abstract

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.

Open circuit voltage generated by dragging superconducting vortices with a dynamic pinning potential

“…Unlike previously investigated spatially confined and time-varying pinning potential [33,34], the dynamic pinning discussed here changes both in space and time. We demonstrate that the induced voltage strongly depends on whether the vortex lattice is dragged parallel or perpendicular to the borders of a superconducting strip.…”

“…(ii) The induced voltage decreases in a stepwise fashion to zero, with the steps corresponding to well defined rates dV x /dv p . This phenomenon is reminiscent of the stroboscopic resonances between the vortex motion under applied current and the frequency of the time-varying dynamic pinning [33,34]. At each step, V x is proportional to v p until it jumps down abruptly to another step.…”

Manipulation of individual superconducting vortices and stick-slip motion in periodic pinning arrays

“…One advantage of the stationary trap geometry is that it is not necessary to include a background pinning potential. Instead of using an applied current to drive vortices past the stationary trap, it is also possible to translate the vortices with dynamic pinning sites by means of sequential flashing of the pinning potential 69,70 .…”

Dynamic Behavior of Vortices under Applied Current Drive in Mesoscopic Superconducting Strip with Two Magnetic Dots

“…Superconductivity at reduced structure dimensions has received an increasing interest mainly due to the huge advancements in modern nanofabrication techniques, which have permitted exploration and discovery of new physical phenomena when approaching the mesoscopic limit (dimensions of the order of coherence length ξ or penetration depth λ), such as the giant vortex state [1], multivortex state [2], vortex-antivortex [3], paramagnetic Meissner effect [4], symmetry-induced antivortices [5], fractional flux vortices [6], and vortices trapped in blind holes [7]. The physics becomes even richer when an electric field is applied to the system in addition to a magnetic field, which will result in the phase-slip phenomenon [8], magnetoresistance oscillations [9], fast moving kinematic vortices [10], and stroboscopic resonances phenomena [11].…”

“…The mesoscopic superconductors have been considered extensively both experimentally and theoretically [1][2][3][4][5][6][7][8][9][10][11] up to now. For theoretic studies, the Ginzburg-Landau (GL) theory [12] is probably the most successful macroscopic description of superconductivity [13].…”