Abstract
A flip-chip-type gradiometer has been constructed with a 10 mm × 5 mm planar DCSQUID gradiometer fabricated on a SrTiO3 bicrystal substrate and a flux transformer made from a YBCO*/YBCO/CeO2/YSZ multilayer on ϕ50.8 mm Si wafer. The coupling coefficient between the flux transformer and the planar gradiometer is 0.18. The transformer increases effectively the resolution of the gradiometer. A magnetic field gradient resolution of 73 fT.cm−1Hz−1/2 in the white region and 596 fT.cm−1Hz−1/2 at 1 Hz has been obtained. High quality magnetocardiogram signals have been successfully measured by using this flip-chip-type gradiometer in an unshielded environment.
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Tian, Y., Wang, T., Chen, K. et al. Flip-chip-type high-T c gradiometer for biomagnetic measurements in unshielded environment. Sci. China Ser. A-Math. 43, 82–87 (2000). https://doi.org/10.1007/BF02903850
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DOI: https://doi.org/10.1007/BF02903850