Reduced Critical Current Spread in Planar MgB2 Josephson Junction Array Made by Focused Helium Ion Beam

Leila Kasaei, Thomas Melbourne, Mengjun Li, Viacheslav Manichev, Fei Qin, Hussein Hijazi, Leonard C. Feldman, Torgny Gustafsson, Bruce A. Davidson, Xiaoxing Xi, Ke Chen

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We have fabricated series arrays of closely spaced planar Josephson junctions on MgB2 films using a 30 keV focused helium ion beam. Uniformity of junction parameters within the arrays is sufficient for achieving phase-lock into an applied microwave signal, and flat giant Shapiro steps are observed. The spread in critical current of a 60-Josephson junction array is estimated to be less than 3.5%, significantly better than reported in MgB2 junctions fabricated by other techniques. These results demonstrate the potential of the focused He+ ion beam irradiation technique in MgB2 Josephson multi-junction circuit applications such as quantum voltage standards.

Original languageEnglish
Article number8661661
JournalIEEE Transactions on Applied Superconductivity
Volume29
Issue number5
DOIs
Publication statusPublished - Aug 2019

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Keywords

  • Focused helium ion microscope (HIM)
  • Josephson junction and series array
  • MgB
  • lumped array
  • voltage metrology

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Kasaei, L., Melbourne, T., Li, M., Manichev, V., Qin, F., Hijazi, H., Feldman, L. C., Gustafsson, T., Davidson, B. A., Xi, X., & Chen, K. (2019). Reduced Critical Current Spread in Planar MgB2 Josephson Junction Array Made by Focused Helium Ion Beam. IEEE Transactions on Applied Superconductivity, 29(5), [8661661]. https://doi.org/10.1109/TASC.2019.2903418