Monolithic 77 K dc SQUID magnetometer

Journal Article · Mon Dec 02 04:00:00 EST 1991 · Applied Physics Letters; (United States)

DOI:https://doi.org/10.1063/1.105790· OSTI ID:6183167

Lee, L P; Char, K; Colclough, M S; Zaharchuk, G ^[1]

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1. Conductus, Inc., Sunnyvale, California (USA)

We report the first fabrication of a monolithic dc SQUID magnetometer that operates above 77 K. We have used bi-epitaxial grain boundary Josephson junctions in YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) to produce the SQUID itself while the flux transformer consists of heteroepitaxial layers of YBCO/SrTiO{sub 3}/LaAlO{sub 3}/SrTiO{sub 3}/YBCO. In the circuit fabricated, the SQUID is built on top of the epitaxial layers of the flux transformer. We have used dry etching, ion-beam cleaning, and photolithographic processing to pattern all the layers. Via contacts and step coverage of the epitaxial wire layers have been achieved without significant degradation of the superconducting properties of any of the three YBCO layers. The magnetometer enhances the magnetic field sensitivity of the bare SQUID by a factor of 127, giving an effective area, {ital d}{Phi}/{ital dB}, of 1.9 mm{sup 2}.

• OSTI ID: 6183167
• Journal Information: Applied Physics Letters; (United States), Journal Name: Applied Physics Letters; (United States) Vol. 59:23; 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
AMINES
AMMONIUM COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTAL STRUCTURE
CUPRATES
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EPITAXY
EQUIPMENT
FABRICATION
FLUXMETERS
GRAIN BOUNDARIES
HIGH-TC SUPERCONDUCTORS
INTEGRATED CIRCUITS
MAGNETOMETERS
MEASURING INSTRUMENTS
MICROELECTRONIC CIRCUITS
MICROSTRUCTURE
MICROWAVE EQUIPMENT
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
QUATERNARY COMPOUNDS
SENSITIVITY
SQUID DEVICES
STABILITY
SUPERCONDUCTING DEVICES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES