Commensurability effects in superconducting Nb films with quasiperiodic pinning arrays

TL;DR

This study experimentally investigates how quasiperiodic pinning arrays in Nb superconducting films influence vortex pinning, revealing enhanced critical currents and matching effects near the transition temperature, aligning with theoretical predictions.

Contribution

It provides experimental evidence of commensurability effects in Nb films with quasiperiodic pinning arrays, confirming theoretical models and demonstrating enhanced vortex pinning.

Findings

Enhanced critical current Ic(B) in quasiperiodic arrays

Matching effects near the transition temperature Tc

Comparison shows superior performance over random or no antidots

Abstract

We study experimentally the critical depinning current Ic versus applied magnetic field B in Nb thin films which contain 2D arrays of circular antidots placed on the nodes of quasiperiodic (QP) fivefold Penrose lattices. Close to the transition temperature Tc we observe matching of the vortex lattice with the QP pinning array, confirming essential features in the Ic(B) patterns as predicted by Misko et al. [Phys. Rev. Lett, vol.95, 177007 (2005)]. We find a significant enhancement in Ic(B) for QP pinning arrays in comparison to Ic in samples with randomly distributed antidots or no antidots.