Integrated high-transition temperature squid-based voltmeters operated at 77 k

H. C. Yang; J. H. Chen; H. E. Horng; S. Y. Yang; J. T. Jen

doi:10.1109/77.784003

Integrated high-transition temperature squid-based voltmeters operated at 77 k

H. C. Yang^*, J. H. Chen, H. E. Horng, S. Y. Yang, J. T. Jen

^*Corresponding author for this work

Undergraduate Program of Electro-Optical Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

The voltage noise levels of high-Tc based YBa₂Cu₃O_y bicrystal SQUIDs and SQUID voltmeters were measured to investigate their noise characteristics. The SQUIDs are of washer type with outer dimension of 90 μm × 90 μm and inner dimension of 20 urn x 20 um. The SQUIDs have a normal inductance of about 60 pH. The integrated modulation and input coils were circular in shape. The modulation coil has a radius of r2 = 80 u.m and r, = 60 [im while the input coil for voltage measurement has radius r, = 50 urn and r, =30 (im. Using a dc bias and standard flux locked loop, the spectral density of the voltage noise, Sv, was observed to behave as I/fat low frequencies and the root mean square flux noise, S2, is white and has a value of ~15 nO0/Hz2 at l kHz. The flux noise levels were reduced to ~ 4 ii-4yHz2 using the ac bias reversing technique. These data suggest that the dominant 1/f voltage noise was caused by critical current fluctuations. We further demonstrate that the 1/f can be induced by flux motion. The voltage noise levels of the SQUID voltmeters are also reported.

Original language	English
Pages (from-to)	4412-4415
Number of pages	4
Journal	IEEE Transactions on Applied Superconductivity
Volume	9
Issue number	2 PART 3
DOIs	https://doi.org/10.1109/77.784003
Publication status	Published - 1999

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Electrical and Electronic Engineering

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10.1109/77.784003

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@article{46d124ad377442c99083e62dd88c4f0a,

title = "Integrated high-transition temperature squid-based voltmeters operated at 77 k",

abstract = "The voltage noise levels of high-Tc based YBa2Cu3Oy bicrystal SQUIDs and SQUID voltmeters were measured to investigate their noise characteristics. The SQUIDs are of washer type with outer dimension of 90 μm × 90 μm and inner dimension of 20 urn x 20 um. The SQUIDs have a normal inductance of about 60 pH. The integrated modulation and input coils were circular in shape. The modulation coil has a radius of r2 = 80 u.m and r, = 60 [im while the input coil for voltage measurement has radius r, = 50 urn and r, =30 (im. Using a dc bias and standard flux locked loop, the spectral density of the voltage noise, Sv, was observed to behave as I/fat low frequencies and the root mean square flux noise, S2, is white and has a value of ~15 nO0/Hz2 at l kHz. The flux noise levels were reduced to ~ 4 ii-4yHz2 using the ac bias reversing technique. These data suggest that the dominant 1/f voltage noise was caused by critical current fluctuations. We further demonstrate that the 1/f can be induced by flux motion. The voltage noise levels of the SQUID voltmeters are also reported.",

author = "Yang, {H. C.} and Chen, {J. H.} and Horng, {H. E.} and Yang, {S. Y.} and Jen, {J. T.}",

note = "Funding Information: Manuscript received September IS, 1998. This work was supported by the National Science Council of R.O.C. under Grants NSC 87-21 12-M002-002 and NSC87-2112-M003-001.",

year = "1999",

doi = "10.1109/77.784003",

language = "English",

volume = "9",

pages = "4412--4415",

journal = "IEEE Transactions on Applied Superconductivity",

issn = "1051-8223",

publisher = "Institute of Electrical and Electronics Engineers Inc.",

number = "2 PART 3",

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T1 - Integrated high-transition temperature squid-based voltmeters operated at 77 k

AU - Yang, H. C.

AU - Chen, J. H.

AU - Horng, H. E.

AU - Yang, S. Y.

AU - Jen, J. T.

N1 - Funding Information: Manuscript received September IS, 1998. This work was supported by the National Science Council of R.O.C. under Grants NSC 87-21 12-M002-002 and NSC87-2112-M003-001.

PY - 1999

Y1 - 1999

N2 - The voltage noise levels of high-Tc based YBa2Cu3Oy bicrystal SQUIDs and SQUID voltmeters were measured to investigate their noise characteristics. The SQUIDs are of washer type with outer dimension of 90 μm × 90 μm and inner dimension of 20 urn x 20 um. The SQUIDs have a normal inductance of about 60 pH. The integrated modulation and input coils were circular in shape. The modulation coil has a radius of r2 = 80 u.m and r, = 60 [im while the input coil for voltage measurement has radius r, = 50 urn and r, =30 (im. Using a dc bias and standard flux locked loop, the spectral density of the voltage noise, Sv, was observed to behave as I/fat low frequencies and the root mean square flux noise, S2, is white and has a value of ~15 nO0/Hz2 at l kHz. The flux noise levels were reduced to ~ 4 ii-4yHz2 using the ac bias reversing technique. These data suggest that the dominant 1/f voltage noise was caused by critical current fluctuations. We further demonstrate that the 1/f can be induced by flux motion. The voltage noise levels of the SQUID voltmeters are also reported.

AB - The voltage noise levels of high-Tc based YBa2Cu3Oy bicrystal SQUIDs and SQUID voltmeters were measured to investigate their noise characteristics. The SQUIDs are of washer type with outer dimension of 90 μm × 90 μm and inner dimension of 20 urn x 20 um. The SQUIDs have a normal inductance of about 60 pH. The integrated modulation and input coils were circular in shape. The modulation coil has a radius of r2 = 80 u.m and r, = 60 [im while the input coil for voltage measurement has radius r, = 50 urn and r, =30 (im. Using a dc bias and standard flux locked loop, the spectral density of the voltage noise, Sv, was observed to behave as I/fat low frequencies and the root mean square flux noise, S2, is white and has a value of ~15 nO0/Hz2 at l kHz. The flux noise levels were reduced to ~ 4 ii-4yHz2 using the ac bias reversing technique. These data suggest that the dominant 1/f voltage noise was caused by critical current fluctuations. We further demonstrate that the 1/f can be induced by flux motion. The voltage noise levels of the SQUID voltmeters are also reported.

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Integrated high-transition temperature squid-based voltmeters operated at 77 k

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