magnetoresistiveisiä

Magnetoresistiveisia refers to the phenomenon where the electrical resistance of a material changes when subjected to an external magnetic field. This effect is observed in various materials and is the basis for a range of sensor technologies. There are several types of magnetoresistance, each with distinct physical mechanisms and applications.

One prominent type is anisotropic magnetoresistance (AMR), which occurs in ferromagnetic materials. The resistance of an AMR material depends on the angle between the current flow and the magnetization direction. Another important effect is giant magnetoresistance (GMR). GMR is observed in thin-film structures composed of alternating ferromagnetic and non-magnetic metallic layers. When an external magnetic field is applied, the relative orientation of the magnetization in the ferromagnetic layers changes, leading to a significant change in resistance.

Tunnel magnetoresistance (TMR) is a quantum mechanical effect that occurs in magnetic tunnel junctions, which consist of two ferromagnetic electrodes separated by a thin insulating barrier. The resistance in a TMR device depends on the relative orientation of the magnetization of the two ferromagnetic layers and the spin polarization of the tunneling electrons. Extraordinary magnetoresistance (EMR) is another phenomenon observed in specific materials and geometries, where a large change in resistance occurs in the presence of a magnetic field, often in materials with high mobility carriers.

These magnetoresistive effects have led to the development of numerous applications, including magnetic field sensors, read heads for hard disk drives, magnetic random-access memory (MRAM), and automotive sensors. The sensitivity, linearity, and operating range of magnetoresistive sensors can be tailored by material selection and device design, making them versatile components in modern electronics.