Magnetic Sensors and Their Applications
IEEE SENSORS JOURNAL, VOL. 6, NO. 3, JUNE 2006
631
Magnetic Sensors and Their Applications
James Lenz and Alan S. Edelstein
Abstract—Magnetic sensors can be classified according to whether they measure the total magnetic field or the vector components of the magnetic field. The techniques used to produce both types of magnetic sensors encompass many aspects of physics and electronics. Here, we describe and compare most of the common technologies used for magnetic field sensing. These include search coil, fluxgate, optically pumped, nuclear precession, SQUID, Hall-effect, anisotropic magnetoresistance, giant magnetoresistance, magnetic tunnel junctions, giant magnetoimpedance, magnetostrictive/piezoelectric composites, magnetodiode, magnetotransistor, fiber optic, magnetooptic, and microelectromechanical systems-based magnetic sensors. The usage of these sensors in relation to working with or around Earth’s magnetic field is also presented. Index Terms—Anisotropic magnetoresistance, fluxgate, giant magnetoresistance, magnetic, magnetic tunnel junctions, magnetoresistance, microelectromechanical systems (MEMS), optically pumped, sensor, spin valves, superconducting quantum interference device (SQUID).
Fig. 1. Estimate of sensitivity of different magnetic sensors. The symbols E and GMN are used to indicate the strength of the Earth’s magnetic field and geomagnetic noise, respectively.
I. INTRODUCTION TO MAGNETIC SENSOR TECHNOLOGIES HIS paper discusses and reviews magnetic sensors and their applications. Magnetic sensors have assisted mankind in analyzing and controlling thousands of functions for many decades. Computers have nearly unlimited memory through the use of magnetic sensors in magnetic storage disks and tape drives. Airplanes fly with higher safety standards because of the high reliability of noncontact switching with magnetic sensors. Automobiles use magnetic sensors to determine position in several places such as the engine crank shaft and wheel
631
Magnetic Sensors and Their Applications
James Lenz and Alan S. Edelstein
Abstract—Magnetic sensors can be classified according to whether they measure the total magnetic field or the vector components of the magnetic field. The techniques used to produce both types of magnetic sensors encompass many aspects of physics and electronics. Here, we describe and compare most of the common technologies used for magnetic field sensing. These include search coil, fluxgate, optically pumped, nuclear precession, SQUID, Hall-effect, anisotropic magnetoresistance, giant magnetoresistance, magnetic tunnel junctions, giant magnetoimpedance, magnetostrictive/piezoelectric composites, magnetodiode, magnetotransistor, fiber optic, magnetooptic, and microelectromechanical systems-based magnetic sensors. The usage of these sensors in relation to working with or around Earth’s magnetic field is also presented. Index Terms—Anisotropic magnetoresistance, fluxgate, giant magnetoresistance, magnetic, magnetic tunnel junctions, magnetoresistance, microelectromechanical systems (MEMS), optically pumped, sensor, spin valves, superconducting quantum interference device (SQUID).
Fig. 1. Estimate of sensitivity of different magnetic sensors. The symbols E and GMN are used to indicate the strength of the Earth’s magnetic field and geomagnetic noise, respectively.
I. INTRODUCTION TO MAGNETIC SENSOR TECHNOLOGIES HIS paper discusses and reviews magnetic sensors and their applications. Magnetic sensors have assisted mankind in analyzing and controlling thousands of functions for many decades. Computers have nearly unlimited memory through the use of magnetic sensors in magnetic storage disks and tape drives. Airplanes fly with higher safety standards because of the high reliability of noncontact switching with magnetic sensors. Automobiles use magnetic sensors to determine position in several places such as the engine crank shaft and wheel