Numerical study of SQUID array responses due to asymmetric junction parameters

TL;DR

This paper numerically investigates how asymmetry in Josephson junction parameters affects the response of SQUID arrays, revealing that array performance improves with junction number when resistances vary.

Contribution

It introduces a detailed numerical analysis of asymmetric Josephson junctions in SQUID arrays, focusing on the effects of critical current and resistance variations on device response.

Findings

Maximum transfer function increases with the number of junctions for arrays with resistance variations.

Linearity improves with more junctions in arrays with asymmetric parameters.

Asymmetry in junction resistances enhances array performance compared to identical junctions.

Abstract

Superconducting quantum interference device arrays have been extensively studied for their high magnetic field sensitivity. The performance of these devices strongly depends on the characteristic parameters of their Josephson junctions, i.e. their critical currents and shunt resistances. Using a resistively shunted junction model and including thermal noise, we perform a numerical investigation of the effects of asymmetric Josephson junctions by independently studying variations in the critical currents and junction resistances. We compare the voltage response of a dc-SQUID with a 1D parallel SQUID array and study the maximum transfer function dependence on the number of junctions in parallel, the screening parameter and thermal noise strength. Our results show that the maximum transfer function and linearity increase with the number of junctions in parallel for arrays with different junction resistances, in contrast to SQUID arrays with identical junctions or with spreads in the critical currents.