We have developed HTS SQUID modules applicable to various systems, such as nondestructive evaluation and low-field NMR/MRI systems. The SQUID module consists of a directly coupled HTS planar gradiometer and a HTS multi-turn input coil, which are fabricated on separate substrates and stacked with a flip-chip configuration. Two types of input coils, 26-turns and 59-turns, are fabricated. The SQUID module is mounted on a printed circuit board with large electrodes for soldering to the external pickup coil. The mutual inductances between the input coil and SQUID varied from 0.5 to 2.3nH, depending on the number of turns of the input coil and the inductance of the SQUID. The SQUID modules with an external pickup coil made of normal metal showed a lower cut-off frequency of 45Hz and a field noise as low as 35fTHz-1/2 (>4kHz).
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