The development of a high-temperature superconducting magnetic sensor (SQUID) has been reported. It is relatively easy to handle in comparison with a Nb SQUID because it can work at liquid nitrogen temperature. This high Tc SQUID has great potential for application in medical diagnostics, nondestructive tests and geological survey, and in other areas. Recently a single channel of the high Tc SQUID was placed on the market. It is expected that this SQUID will accelerate the development of SQUID applications.
