Open AccessPerformance of Digital SQUID with Sub-Flux Quantum Feedback Resolution Fabricated using 10 kA/cm2 Nb Process
Author(s) -
Kimio Itagaki,
Itta Oshima,
Yuichi Hasegawa,
Ryo Matsunawa,
Mitsuhide Naruse,
Tohru Taino,
Hiroaki Myoren
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1590/1/012038
Subject(s) - oversampling , squid , physics , flux (metallurgy) , analytical chemistry (journal) , nuclear magnetic resonance , materials science , optoelectronics , chemistry , cmos , ecology , chromatography , metallurgy , biology
Digital superconducting quantum interference device (SQUID with Single Flux Quantum (SFQ) feedback operates as a Δ-type oversampling A/D converter. Magnetic flux resolution at Nyquist frequency can be improved by taking sub SFQ feedback resolution and large oversampling ratio. Using high critical current density Nb process for fabricating SFQ circuits, we expected more higher operation speed for the digital SQUID and resulting to higher magnetic flux resolutions. We expected a performance of the digital SQUID magnetometer fabricated using 10 kA/cm 2 Nb process based on CAD layout, with an up/down counter using T 2 FF cells and parallel SFQ feedback. For the clock frequency of 13 GHz and the Nyquist frequency of 1.587 MHz, the magnetic field noise was lower than 1.5 fT / Hz and the slew rate was exceeded 500 mT/s.