The origin of the giant magnetoresistance of magnetic multilayers and magnetic granular solids is investigated through a unified spin‐dependent linear transport theory, in which the primary source of electrical resistivity is short‐range scattering by impurities in the different magnetic or nonmagnetic regions and at the interfaces. Our theory predicts that magnetotransport in granular solids is similar to that for currents perpendicular to the plane of the layers in multilayers in that their magnetoresistance is independent of the average distance between adjacent magnetic regions.
Camblong, Horacio E., "Theory of Magnetotransport in Inhomogeneous Magnetic Structures" (1994). Physics and Astronomy. 16.