High-Tc Electronic Planar Gradiometer Constructed From Magnetometers on a Chip.

We have fabricated a high-Tc electronic planar gradiometer composed of dc SQUIDs on a 10 mm × 10 mm SrTiO3 bicrystal substrate. The SQUIDs were patterned in a single-layer YBa2Cu3Oτ-δ thin film which is prepared by pulsed laser deposition. The outputs of the magnetometers are added and subtracted by analog electronic circuits to form the gradiometer. These magnetometers could be used to construct two sets electronic planar first-order gradiometers or an electronic planar second-order gradiometer, which could measure the elements ∂Bz/∂x and ∂Bz/∂y or ∂² Bz/∂x∂y, respectively. The noise spectra of each magnetometer and a first-order electronic planar gradiometer were measured. [ABSTRACT FROM AUTHOR]