ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We measured the performance of dc superconducting quantum interference devices (SQUIDs) fabricated from YBa2Cu3O7−δ films as a function of the SQUID inductance, L, and normal resistance, Rn, of step-edge Josephson junctions and compared it to theoretical expectations. A process for adjusting critical currents and obtaining high normal resistances of junctions has been developed. All measurements were performed in liquid nitrogen, i.e., at 77 K. We could obtain controllably normal resistances of 5–10 Ω per junction at critical currents of 20–50 μA. A spectral density of white flux noise of SΦ1/2=2.5μΦ0/(square root of)Hz was obtained with a dc SQUID having L=50 pH, Rn=7 Ω per junction, βL=0.5 and ∂V/∂Φ=110 μV/Φ0. The best magnetic field resolution at 1 kHz was 20 fT/(square root of)Hz, with L=150 pH. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.117631
Permalink
