A MODEL FOR GIANT MAGNETORESISTANCE IN MAGNETIC GRANULAR SOLIDS

We propose a model for giant magnetoresistance (GMR) in granular magnetic solids where the moments within a grain form a single ferromagnetic domain. The electrical transport properties of such solids due to (1) the scattering from grains that act as centers for the potential barrier and (2) the magnetic scattering due to the dipole-dipole interaction between a ferromagnetic domain and spin of a conduction electron are calculated. The magneto-conductance computed as a function of the grain size and the global magnetization shows that GMR in magnetically inhomogenous media may arise from the interplay between the potential-barrier and the magnetic scatterings.