Magnetoresistive Sensors

Magnetoresistive (MR) sensors are linear magnetic field transducers based either on the intrinsic magnetoresistance of the ferromagnetic (FM) material (sensors based on the spontaneous resistance anisotropy in 3D FM alloys, also called anisotropic magnetoresistance sensors) or on FM/nonmagnetic heterostructures (giant magnetoresistance multilayers, spin valve, and tunneling magnetoresistance devices). This chapter describes the principles, materials, and the structures of MR devices, and discusses the classes of these devices focusing on their different applications. It also describes the real applications in which the MR devices have demonstrated their capabilities. MR sensors are widely used in various applications. The most important are their applications as read heads. MR sensors are also used as mechanical transducers and of course as magnetic field sensors, for example, in compasses. The progress in thin film MR sensors is possible due to the large scientific and business interest.