First Derivative High-Tc SQUID Gradiometers with Narrow Structure from Single Layer YBCO Thin Film

Mizushi MATSUDA  Tsutomu MATSUURA  Koichi KATO  Hiroshi OYAMA  Amane HAYASHI  Satoru HIRANO  Shinya KURIKI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.3   pp.677-680
Publication Date: 2002/03/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Superconductive Electronics)
Category: SQUIDs and Their Applications
Keyword: 
SQUID,  gradiometer,  low frequency noise,  

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Summary: 
We have fabricated and characterized two types of high-Tc planar SQUID gradiometers having different line width of pickup loops. The device worked in flux-locked loop (FLL) operation even in laboratory environment without any shielding. A magnetic field gradient resolution of a parallel-type device in a lightly shielded room was about 0.5 pT/cmHz1/2 at 1 kHz and 2 pT/cmHz1/2 at 1 Hz. The device was possible to record magnetocardiograms in a shielded room. QRS-complex peaks of about 10 pT PP/4mm are clearly observed. For a mesh-type device, the increase of low frequency noise in the open laboratory environment was less than that for a parallel-type.