Highly Effective Superconducting Vortex Pinning in Conformal Crystals

TL;DR

This study demonstrates that conformal crystal patterns of artificial pinning centers significantly enhance vortex pinning in superconducting films, outperforming traditional lattice arrangements and maintaining effectiveness over wide magnetic fields.

Contribution

The paper introduces a novel conformal crystal pattern for artificial pinning centers that achieves superior vortex pinning in superconductors compared to conventional patterns.

Findings

Magneto-resistance is significantly reduced in conformal crystal patterns.

Conformal crystals exhibit magneto-resistance below noise floor over wide magnetic fields.

Enhanced vortex pinning is due to commensurability with pattern stripes, not lattice compression.

Abstract

We have investigated the vortex dynamics in superconducting thin film devices with non-uniform patterns of artificial pinning centers (APCs). The magneto-transport properties of a conformal crystal and a randomly diluted APC pattern are compared with that of a triangular reference lattice. We have found that in both cases the magneto-resistance below the first matching field of the triangular reference lattice is significantly reduced. For the conformal crystal, the magneto-resistance is below the noise floor indicating highly effective vortex pinning over a wide magnetic field range. Further, we have discovered that for asymmetric patterns the R vs. H curves are mostly symmetric.This implies that the enhanced vortex pinning is due to the commensurability with a stripe in the non-uniform APC pattern and not due to a rearrangement and compression of the whole vortex lattice.