The Impact of High-Temperature Superconductivity on SQUID Magnetometers.

DC and RF Superconducting QUantum Interference Devices (SQUIDs) fabricated from low transition temperature (T(c)) superconductors and operated at liquid (4)He temperatures are routinely used as ultrasensitive detectors in many applications, for example, as magnetometers, magnetic gradiometers, voltmeters, and motion detectors. SQUIDs fabricated from high T(c) superconductors such as YBa(2)Cu(3)O(7) and operated in liquid nitrogen at 77 K offer a greater convenience in operation at the expense of a poorer noise performance, particularly at low frequencies. The resolution of SQUID-based magnetometers is compared with that of other types of magnetometers operatng at ambient temperatures.