Low-noise, single-layer YBa/sub 2/Cu/sub 3/O/sub 7-x/ DC SQUID magnetometers at 77 K

Author

Cantor, R. ; Lee, L.P. ; Teepe, M. ; Vinetskiy, V. ; Longo, J.

Author_Institution

Conductus Inc., Sunnyvale, CA, USA

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

2927

Lastpage

2930

Abstract

We describe a low-noise dc Superconducting QUantum Interference Device (SQUID) magnetometer that is fabricated from a single layer of YBa/sub 2/Cu/sub 3/O/sub 7-x/ on a 2 cm/spl times/2 cm bicrystal substrate. The magnetometer design consists of a single-turn pickup loop that is directly coupled to a low inductance SQUID. Using conventional flux-locked loop electronics with bias current reversal, the white flux noise of several of these magnetometers operated at 77 K is observed to be as low as 2.2 /spl mu//spl Phi//sub 0///spl radic/Hz above 10 kHz, increasing to about 5.7 /spl mu//spl Phi//sub 0///spl radic/Hz at 1 Hz. The field-to-flux conversion efficiency is measured to be 4.6 nT//spl Phi//sub 0/, resulting in a white magnetic field noise of to fT//spl radic/Hz above 10 kHz, increasing to 26 fT//spl radic/Hz at 1 Hz.<>

Keywords

SQUID magnetometers; barium compounds; high-temperature superconductors; superconducting device noise; white noise; yttrium compounds; 1 Hz to 10 kHz; 77 K; DC SQUID magnetometers; YBa/sub 2/Cu/sub 3/O/sub 7-x/ single layer; YBa/sub 2/Cu/sub 3/O/sub 7/; bias current reversal; bicrystal substrate; field-to-flux conversion efficiency; flux-locked loop; inductance; magnetic field noise; single-turn pickup loop; white flux noise; Couplings; Current measurement; Inductance; Interference; Magnetic field measurement; SQUID magnetometers; Superconducting device noise; Superconducting devices; Superconducting epitaxial layers; White noise;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403205

Filename

403205