Open AccessReduced Critical Current Spread in Planar MgB2 Josephson Junction Array Made by Focused Helium Ion Beam
Author(s) -
Leila Kasaei,
Thomas Melbourne,
Mengjun Li,
Viacheslav Manichev,
Fei Qin,
Hussein Hijazi,
L. C. Feldman,
Torgny Gustafsson,
B. A. Davidson,
Xiaoxing Xi,
Ke Chen
Publication year - 2019
Publication title -
ieee transactions on applied superconductivity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.467
H-Index - 84
eISSN - 1558-2515
pISSN - 1051-8223
DOI - 10.1109/tasc.2019.2903418
Subject(s) - josephson effect , planar , pi josephson junction , materials science , ion , microwave , superconductivity , ion beam , helium , superconducting tunnel junction , optoelectronics , beam (structure) , physics , condensed matter physics , atomic physics , optics , computer science , computer graphics (images) , quantum mechanics
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.
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