An absolute magnetometer based on dc superconducting quantum interference devices

We propose a novel device, based on a series of dc SQUIDs (direct current Superconducting QUantum Interference Devices), each one with different sensitive area, that can be used to perform absolute measurements of magnetic field. With this array, we overcome the limit of a single dc SQUID of being sensitive only to variations of the linked magnetic flux. The overall voltage-flux characteristic of our device, in fact, has a non-periodic shape that allows a clear identification of the point with zero magnetic field. We present a discussion of the working principle and of the main characteristics, which have been partially tested on a prototype.