Experimental operation of an RS flip-flop composed of nonlatching Josephson gates

Yoshinao Mizugaki, Takeshi Onomi, Koji Nakajima, Tsutomu Yamashita

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We present the experimental implementation of an RS flip-flop (RS-FF) composed of dc-biased coupled-SQUID (C-SQUID) gates. The C-SQUID gate is a combination of a single-junction SQUID and a double-junction SQUID. This gate utilizes nonhysteretic Josephson functions and it is operated in nonlatching mode with dc-biasing. Several logical functions are able to be realized with a C-SQUID gate by adjusting the input bias and the input signal levels. The speed performance of the gate is evaluated by simulation for ring oscillators, and the minimum switching delay of 65 ps/stage is obtained under Josephson critical current density of 10 kA/cm2. We have fabricated the RS-FF composed of two C-SQUID NOR gates. The circuit is integrated using a Nb/AlOx/Nb junction technology and its operation is demonstrated experimentally.

Original languageEnglish
Pages (from-to)90-93
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number2
Publication statusPublished - 1996 Jun
Externally publishedYes

ASJC Scopus subject areas

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


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