Highly sensitive uncooled magnetometers: State of the art. superconductingmagnetic hybrid magnetometers, an alternative to SQUIDs?

We discuss the performances of highly sensitive magnetometers using flux ga tes, as well as magnetotransport effects (magnetoresistance-AMR/GMR and mag netoimpedance-GMI), Soft magnetic materials operating at room temperature o r cryogenic temperatures are involved in these effects. We report on their performances (sensitivity, bandwidth, etc.) with emphasis on their noise pr operties. The latter often fall to 1 - 10 pT/root Hz even for active areas as low as 1 - 2 mm(2). Amorphous magnetic flux guides are often used to enh ance the field sensitivity of micro-devices. Their replacement by supercond ucting concentrators, which could lead to much larger gain factors, is disc ussed. This review, together with new results, confirms a new research held which could lead to highly sensitive, low noise, superconducting-magnetic hybrid magnetometers.