Magnetoresistiivistä

Magnetoresistiivistä refers to the phenomenon where the electrical resistance of a material changes when subjected to an external magnetic field. This change in resistance is not due to a change in the material's physical dimensions but rather a modification of its electronic properties by the magnetic field. The effect can be positive, where resistance increases with the magnetic field, or negative, where resistance decreases.

There are several types of magnetoresistance. Anisotropic magnetoresistance (AMR) is observed in ferromagnetic materials and depends on the angle between the current flow and the magnetization direction. Giant magnetoresistance (GMR) is a much larger effect observed in multilayers of ferromagnetic and non-magnetic conductive materials. Spin-dependent scattering of electrons at the interfaces between these layers leads to a significant change in resistance depending on the relative orientation of the magnetization in the ferromagnetic layers. Tunnel magnetoresistance (TMR) is another effect seen in magnetic tunnel junctions, where two ferromagnetic layers are separated by a thin insulating barrier. The resistance in TMR devices depends on the relative orientation of the magnetization of the two ferromagnetic layers and is due to quantum mechanical tunneling of electrons through the barrier.

Magnetoresistive materials and effects have found widespread applications in various technologies. They are crucial components in magnetic sensors, read heads for hard disk drives, magnetic random-access memory (MRAM), and current sensors. The sensitivity and controllability of magnetoresistance make it a valuable tool for detecting and measuring magnetic fields, enabling precise data storage and retrieval.