In thin alloy films consisting primarily of nickel, iron, copper, and other ferromagnetic metals that are used in magnetoresistance elements, when the ferromagnetic metals are subjected to an external magnetic field, at the molecular level, rotation in the 3d-band electron orbital plane occurs, and combined with the interaction of the inherent spin orbit of the electrons,
this causes distortion in the 3d-band electron distribution (d-band wave function is distorted).
As a result, the electrons seek energy stability, and this incites a change in the conduction electron probability of occurrence in the 4s-band, which is a different electron orbit, and this state is manifested as a change in electrical resistance.
Millitesla. Name for unit of magnetic flux density. (SI units)
The conversion with the CGS unit of gauss is 1mT = 10 gauss.