Search

A prototype three-axis magnetometer has been developed, intended for geophysical applications, involving high-transition temperature dc superconducting quantum interference devices (SQUIDs). Each SQUID was fabricated from a thin film of YBa[sub 2]Cu[sub 3]O[sub 7-x] deposited on a SrTiO[sub 3] bicrystal to form two Josephson junctions, and was directly coupled to a single-turn pickup loop patterned in the same film. The three orthogonally mounted sensors were immersed in liquid nitrogen in a fiberglass Dewar and operated in separate flux-locked loops. In nominally zero ambient magnetic field, the best magnetic field resolution was 170 fT Hz[sup -½] in the white noise, increasing to 225 fT Hz[sup -½] at 1 Hz. The dynamic range was ±1.6 × 10[sup 6] Hz[sup ½] in the white noise, and the highest slew rate achieved was 1.6 mT s[sup -1], at 900 Hz. The 3 dB point in the frequency response was about 90 kHz. The three channels were mutually orthogonal to about 1%. The three-axis magnetometer was also operated outside the laboratory in the presence of 60 Hz and radio-frequency noise. [ABSTRACT FROM AUTHOR]

Examines the fabrication of low-noise YBCO superconducting quantum interference device magnetometers on SrTiO3 bicrystal substrates. Function of Josephson junctions; Composition of the magnetometer design; Device exhibiting large voltage modulation with applied flux.