superconducting quantum interference device (sensor) (SQUID)

SQUID is the abbreviation for Superconducting Quantum Interference Device. These units are based on quantum interference, which occurs in superconductivity.

SQUID is a highly sensitive magnetic field sensor that can measure magnetic flux densities in the range of quadrillionths of a Tesla (T), equivalent to `10^-15`. The sensitivity of SQUID sensors is several orders of magnitude higher than that of AMR or GMR sensors.

SQUID sensors are used in medicine to measure brain waves and in magnetic resonance tomographs.