Large Magnetoresistance Oscillations in Mesoscopic Superconductors Due to Current-Excited Moving Vortices

TL;DR

This paper demonstrates that in mesoscopic superconductors, large magnetoresistance oscillations are primarily caused by current-excited moving vortices, which differ from the traditional Little-Parks effect and are influenced by applied current and vortex dynamics.

Contribution

It reveals that current-excited moving vortices induce significant magnetoresistance oscillations in mesoscopic superconductors, highlighting a different mechanism from the Little-Parks effect.

Findings

Large resistance oscillations due to vortex motion.

Oscillations depend on applied current and magnetic field.

Vortex dynamics influence magnetoresistance in mesoscopic samples.

Abstract

We show in the case of a superconducting Nb ladder that a mesoscopic superconductor typically exhibits magnetoresistance oscillations whose amplitude and temperature dependence are different from those stemming from the Little-Parks effect. We demonstrate that these large resistance oscillations (as well as the monotonic background on which they are superimposed) are due to {\it current-excited moving vortices}, where the applied current in competition with the oscillating Meissner currents imposes/removes the barriers for vortex motion in increasing magnetic field. Due to the ever present current in transport measurements, this effect should be considered in parallel with the Little-Parks effect in low-$T_c$ samples, as well as with recently proposed thermal activation of dissipative vortex-antivortex pairs in high-$T_c$ samples.