Superconductive quantum interference detector magnetometer for high-precision measurement of magnetic fields uses superconductive closed loops with multiple Johnson contacts

摘要

Current loops form a superconductive quantum interference filter (SQIF) (1). Three cells are so designed that, under an existing magnetic field, the screening currents flowing in the cells generate no magnetic flux in most cells that is greater than an elementary flux quantum. An electric feedback loop (4a,4b) links to an electronics unit (5) and couples magnetically to the SQIF.