Low 1/ f noise single-layer YBa sub 2 Cu sub 3 O sub x dc SQUID at 77 K

Journal Article · Mon Jun 15 04:00:00 EDT 1992 · Applied Physics Letters; (United States)

DOI:https://doi.org/10.1063/1.106752· OSTI ID:7182581

Friedl, G; Vildic, M; Roas, B; Uhl, D; Boemmel, F; Roemheld, M; Hillenbrand, B; Stritzker, B; Daalmans, G ^[1]

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1. SIEMENS AG, Research Laboratories, 8520 Erlangen (Germany)

Autonomous single-layer dc superconducting quantum interference devices (SQUIDs) have been prepared from epitaxial, laser-deposited YBa{sub 2}Cu{sub 3}O{sub {ital x}} films on step edge SrTiO{sub 3} and LaAlO{sub 3} substrates. For device patterning, a SiO{sub {ital x}} inhibit technique as well as conventional ethylenediaminetetraacetic wet etch was used. The Josephson junctions are of grain boundary type. Their widths are 5 {mu}m. The SQUID hole is a square of about 5 {mu}m; the SQUID inductance is estimated to be about 20 pH. We obtained a very regular, nonhysteretic flux to voltage modulation over more than 100 flux quanta ({Phi}{sub 0}). The maximum voltage signal is of the order of 15 {mu}V peak to peak and the maximum transfer function {ital dV}/{ital d}{Phi} at the appropriate flux bias is 50 {mu}V/{Phi}{sub 0} at 77 K. The best value of the equivalent flux noise as measured in the flux locked loop mode is 1.4{times}10{sup {minus}5} {Phi}{sub 0}/Hz{sup 1/2} at 1 Hz and 1{times}10{sup {minus}5} {Phi}{sub 0}/Hz{sup 1/2} in the white noise region for {ital f}{gt}5 Hz. This results in an energy resolution {epsilon}{sub {ital n},{ital w}}({ital f}{gt}5 {ital Hz})=1{times}10{sup {minus}29} {ital J}/{ital Hz} {ital in} {ital the} {ital white} {ital noise} {ital region} {ital and} 2{times}10{sup {minus}29} {ital J}/{ital Hz} {ital at} 1 {ital Hz}.

• OSTI ID: 7182581
• Journal Information: Applied Physics Letters; (United States), Journal Name: Applied Physics Letters; (United States) Vol. 60:24; ISSN APPLA; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

665412* -- Superconducting Devices-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
ELECTRONIC EQUIPMENT
EPITAXY
EQUIPMENT
ETCHING
FLUXMETERS
GRAIN BOUNDARIES
HIGH-TC SUPERCONDUCTORS
JOSEPHSON JUNCTIONS
JUNCTIONS
MEASURING INSTRUMENTS
MICROSTRUCTURE
MICROWAVE EQUIPMENT
NOISE
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTORS
SURFACE FINISHING
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES