Conductivity and magnetoresistance in magnetic granular films (invited)

The transport properties in magnetic granular films are modeled by considering the spin-dependent impurity scattering within the granules and the interface roughness scattering at the boundaries of the granules. The magnetoresistance for these films is derived by using the formalism developed for layered structures with currents perpendicular to the plane of the layers and which is applicable to random systems. With this model, various features of the magnetoresistance observed in recent experiments can be explained and the optimal choice of parameters to maximize the magnetoresistance can be determined.