Fabrication of Nb/Al(AlOx)/Nb DC SQUID by focused ion beam sculpturing

TL;DR

This paper reports the fabrication of highly reproducible Nb/Al(AlOx)/Nb DC SQUIDs using focused ion beam etching, demonstrating high flux modulation and a range of critical currents, advancing superconducting quantum interference device technology.

Contribution

The study introduces a novel fabrication method for Nb/Al(AlOx)/Nb DC SQUIDs with high reproducibility and tunable critical currents using focused ion beam sculpturing.

Findings

High modulation factor of 92% at 4.2 K

Critical current range from 25 to 1100 microamperes

Successful fabrication of both hysteretic and non-hysteretic SQUIDs

Abstract

Highly reproducible Nb/Al(AlOx)/Nb Josephson junction based direct current superconducting quantum interference devices (DC SQUID) were fabricated by three dimensional etching using focused ion beam. Hysteretic and non-hysteretic DC SQUID with critical current ranging from 25 to 1100 microampere were fabricated by varying the Al barrier and oxygen exposure time. The fabricated DC SQUIDs have shown periodic flux dependence with high modulation factor reaching a value of 92% at 4.2 K.