HIGH-T-C SUPERCONDUCTING GRADIOMETER WITH A LONG-BASE-LINE ASYMMETRICFLUX TRANSFORMER

The planar gradiometer consists of a directly coupled magnetometer ind uctively coupled to the smaller loop of an asymmetric, two-loop flux t ransformer patterned in a single film of YBa2Cu3O7-x. The coupling is adjusted mechanically to balance the gradiometer to about 1 part in 30 00 with respect to fields perpendicular to its plane. The baseline is 48 mm and the intrinsic balance with respect to in-plane fields about 1 part in 1400. When a magnetic field is applied solely to the magneto meter, its sensitivity is reduced by only 5% by the presence of the fl ux transformer. (C) 1997 American Institute of Physics.