Transverse vortex commensurability effect and sign change of the Hall voltage in superconducting YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ thin films with a nanoscale periodic pinning landscape

TL;DR

This study demonstrates how a nanoscale periodic pinning landscape in YBa₂Cu₃O₇−δ thin films causes a transverse vortex commensurability effect, including a sign change in the Hall voltage, linked to vortex pinning and matching conditions.

Contribution

It reveals the impact of artificial periodic pinning on vortex behavior and Hall voltage sign change in high-temperature superconductor thin films.

Findings

Observation of a narrow peak in the Hall coefficient with reversed polarity.

Commensurability effect linked to vortex pinning at the artificial lattice.

Disappearance of the effect at higher vortex velocities.

Abstract

The transverse (Hall) voltage in thin films of the high-temperature superconductor YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ with an artificial periodic pinning array is investigated. Columnar defect regions along the crystallographic $c$ axis, in which superconductivity is suppressed, are created by irradiation with He$^+$ ions through a silicon stencil mask. The commensurate arrangement of magnetic flux quanta with the artificial defect lattice is confirmed by maxima of the critical current and minima of the resistance, respectively. The magnetic field dependence of the transverse voltage reveals a commensurability effect characterized by a narrow peak of the Hall coefficient with reversed polarity compared to the background signal. This signature of vortex matching disappears at larger vortex velocities substantiating its close connection with enhanced pinning of vortices at the periodic pinning landscape.