Dc SQUID based on unshunted Josephson junctions: experimental results

Author

Seppa, H. ; Kiviranta, M. ; Gronberg, L.

Author_Institution

Measurement Technol., VTT Automation, Finland

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

3248

Lastpage

3251

Abstract

It has been proposed that a new SQUID type be constructed by using unshunted Josephson junctions instead of resistively shunted junctions. Using this approach we are able to present a SQUID having a high output dynamic resistance and a device characterized by a negative output resistance and an extremely low noise. The first mentioned is called a high-gain SQUID, the latter an unshunted SQUID. This article describes preliminary experiments obtained from the SQUIDs based on this concept. The iv characteristics are shown to resemble the theoretically predicted characteristics but the noise performance was higher than expected. Most likely the reason for the high noise was the imperfect damping of the SQUID in the frequencies near 1 GHz.<>

Keywords

Josephson effect; SQUIDs; superconducting device noise; 1 GHz; DC SQUID; I-V characteristics; damping; dynamic resistance; high-gain SQUID; negative resistance; noise; unshunted Josephson junctions; unshunted SQUID; Automation; Circuit noise; Damping; Frequency; Josephson junctions; Low-frequency noise; Resistors; SQUIDs; Superconducting device noise; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403284

Filename

403284