Asynchronous Digital SQUID Magnetometer With an On-Chip Magnetic Feedback for Improvement of Magnetic Resolution

Author

Tsuga, Y. ; Yamanashi, Y. ; Yoshikawa, N.

Author_Institution

Dept. of Electr. & Comput. Eng., Yokohama Nat. Univ., Yokohama, Japan

Volume

23

Issue

3

fYear

2013

fDate

Jun-13

Firstpage

1601405

Lastpage

1601405

Abstract

An asynchronous digital superconducting quantum interference device (SQUID) with complementary output, which needs no periodic high-frequency readout clock input, has been investigated. The magnetic flux resolution of the asynchronous digital SQUID has been improved using an on-chip magnetic feedback. A wide dynamic range asynchronous digital SQUID magnetometer system with improved magnetic resolution has been devised using alternating readout of two digital SQUIDs placed in parallel. The slew rate and the dynamic range of the asynchronous digital SQUID magnetometer were estimated to be 4 × 10¹⁰ Φ₀/s and quite large, respectively. We have designed the asynchronous digital SQUID magnetometer system using 2.5 kA/cm² Nb process. We have experimentally confirmed the magnetic flux resolution of less than flux quantum (Φ₀) and the good linearity of the magnetic response of the asynchronous digital SQUID magnetometer system up to 3000 Φ₀.

Keywords

SQUID magnetometers; asynchronous circuits; magnetic flux; niobium; type II superconductors; Nb; asynchronous digital SQUID magnetometer system; asynchronous digital superconducting quantum interference device; complementary output; dynamic range; magnetic flux resolution; magnetic response; on-chip magnetic feedback; slew rate; Dynamic range; Magnetic flux; Magnetic tunneling; SQUID magnetometers; SQUIDs; System-on-a-chip; Digital superconducting quantum interference device (SQUID); SQUID; dynamic range; single flux quantum circuit;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2012.2235901

Filename

6392890