Low-noise SQUID

Patent · Sat Jan 01 00:00:00 EST 2000

OSTI ID:872850

Dantsker, Eugene ^[1]; Clarke, John ^[2]

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1. Torrance, CA
2. Berkeley, CA

The present invention comprises a high-transition-temperature superconducting device having low-magnitude low-frequency noise-characteristics in magnetic fields comprising superconducting films wherein the films have a width that is less than or equal to a critical width, w.sub.C, which depends on an ambient magnetic field. For operation in the Earth's magnetic field, the critical width is about 6 micrometers (.mu.m). When made with film widths of about 4 .mu.m an inventive high transition-temperature, superconducting quantum interference device (SQUID) excluded magnetic flux vortices up to a threshold ambient magnetic field of about 100 microTesla (.mu.T). SQUIDs were fabricated having several different film strip patterns. When the film strip width was kept at about 4 .mu.m, the SQUIDs exhibited essentially no increase in low-frequency noise, even when cooled in static magnetic fields of magnitude up to 100 .mu.T. Furthermore, the mutual inductance between the inventive devices and a seven-turn spiral coil was at least 85% of that for inductive coupling to a conventional SQUID.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 6023161
• OSTI ID: 872850
• Country of Publication: United States
• Language: English

Related Subjects

low-noise
squid
comprises
high-transition-temperature
superconducting
device
low-magnitude
low-frequency
noise-characteristics
magnetic
fields
comprising
films
width
equal
critical
depends
ambient
field
operation
earth
micrometers
film
widths
inventive
transition-temperature
quantum
interference
excluded
flux
vortices
threshold
100
microtesla
squids
fabricated
strip
patterns
kept
exhibited
essentially
increase
noise
cooled
static
magnitude
furthermore
mutual
inductance
devices
seven-turn
spiral
coil
85
inductive
coupling
conventional
ambient magnetic
superconducting film
quantum interference
magnetic flux
magnetic field
magnetic fields
temperature superconducting
static magnetic
superconducting quantum
interference device
superconducting device
mutual inductance
frequency noise
superconducting films
conducting films
inductive coupling
comprising superconducting
film strip
conducting film
transition-temperature superconducting
high-transition-temperature superconducting
low-noise squid
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