Improvement of high T/sub c/ SQUID performance using an integrated resistor

Author

Tarte, E.J. ; Kang, D.J. ; Booij, W.E. ; Coleman, P.D. ; Moya, A. ; Baudenbacher, F. ; Moon, S.H. ; Blamire, M.G.

Author_Institution

Interdisciplinary Res. Centre in Supercond., Cambridge Univ., UK

Volume

9

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

4432

Lastpage

4435

Abstract

The performance of high T/sub c/ SQUIDs with resistively shunted inductances have been investigated. We find that the voltage modulation depth /spl Delta/V of shunted 83 pH SQUIDs is significantly larger than that of unshunted SQUIDs with similar parameters and increases with the parameter /spl gamma/=R/sub n//R/sub s/ as expected from theory (R/sub n/ is the junction resistance and R/sub s/ the shunt resistance). We also find that the conventional decrease of /spl Delta/V with SQUID inductance L can be eliminated leaving only the effect of the thermal noise flux. In this way /spl Delta/V=63 /spl mu/V has been achieved for a bicrystal SQUID at 77 K whose screening parameter /spl beta//sub L/=13. Noise measurements performed on this SQUID indicate that the resistor in circuit does not increase the noise.

Keywords

SQUIDs; bicrystals; high-temperature superconductors; superconducting device noise; thermal noise; bicrystal SQUID; high T/sub c/ superconductor; integrated resistor; junction resistance; resistively shunted inductance; screening parameter; shunt resistance; thermal noise flux; voltage modulation depth; Annealing; Critical current; Electron beams; Inductance; Magnetic modulators; Noise measurement; Resistors; SQUIDs; Strips; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.784008

Filename

784008