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 aTesla
(T), equivalent to 10exp-15. Thesensitivity 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 imaging.