Magnetic Sensors

Abstract

The different types of vector and scalar or total field magnetic sensors and the applications of these sensors are reviewed. Some of the applications have been employed for many years, such as the compasses for navigation, while others such as the detection of magnetic nanoparticles as part of drug delivery systems are much newer. Among the new phenomena are preferential tunneling of electrons with one direction of spin to increase the magnetoresistance or to change the magnetization using MgO tunnel barrier and Bose condensates for high‐resolution magnetometry. The several points that will be emphasized are the following: (i) magnetic sensors generally differ greatly in sensitivity, cost, power, and size; (ii) many different phenomena can be employed to measure magnetic fields; (iii) there are a large number and variety of applications; and (iv) the discovery of new phenomena has opened up new ways to measure magnetic fields and applications.