Advances in magnetometry

This article describes many of the advances in magnetometry. Because much of the recent progress in magnetometry is built on current technology, and to put these advances in the proper perspective, a general discussion of magnetometry will also be presented. The progress includes a remarkable increase in the magnetoresistance of some devices, improved signal processing, and some new types of magnetometer. The large increase in magnetoresistance is a result of an increased understanding of quantum mechanical spin dominated transport in restricted geometries such as multilayers and magnetic tunnel junctions. The new types of magnetometer include magnetoelectric sensors, extraordinary magnetoresistance sensors, and sensors that incorporate MEMS technology. These advances in magnetometer technology offer orders of magnitude increases in sensitivity and/or large decreases in cost and power consumption. Major technological limitations of current magnetic sensors are also discussed.