ABSTRACT
The superconducting quantum interference device (SQUID) is the most sensitive detector of the magnetic flux. This feature makes the SQUID an attractive device for a range of applications. The SQUIDs based on low-Tc superconductors have shown unsurpassed sensitivity for the measurement of current, voltage, magnetic field, and magnetic field gradient (1). Potentiality of the applications of these SQUID magnetometers in measuring the biomagnetic field (2), nondestructive testing (2), and geological prospecting (3) have been demonstrated much earlier. In spite of the commercial availability of low-Tc SQUID for several years, the SQUID-based applications did not gain widespread acceptability. This has been mainly due to the inconvenience of its operation at liquid-helium temperature.
