Influence of nonuniform critical current density profile on magnetic field behavior of AC susceptibility in 2D Josephson Junction Arrays

TL;DR

This study investigates how nonuniform critical current density profiles affect the magnetic field response of AC susceptibility in highly ordered 2D Josephson junction arrays, using mutual-inductance measurements and a single-plaquette model.

Contribution

It introduces a model considering inhomogeneous critical current distribution to explain magnetic field dependence of AC susceptibility in 2D Josephson arrays.

Findings

Inhomogeneous critical current profiles influence AC susceptibility behavior.

The single-plaquette overdamped model successfully explains experimental observations.

Mutual-inductance measurements validate the theoretical approach.

Abstract

Employing mutual-inductance measurements we study the magnetic field dependence of complex AC susceptibility of artificially prepared highly ordered (periodic) two-dimensional Josephson junction arrays of unshunted Nb-AlO_x-Nb junctions. The observed behavior can be explained assuming single-plaquette approximation of the overdamped model with an inhomogeneous critical current distribution within a single junction.