Spin-dependent Boltzmann equation and GMR in metallic granular systems

Based on explicit treatment of spin-dependent components of non-equilibrium distribution function within the formalism of Boltzmann equation, the problem of magnetotransport in a system of magnetic granules embedded into a non-magnetic metallic host has been considered. For a specific model of spin-dependent perturbation potential by the granules, an exact solution for distribution function has been found, yielding a magnetoresistance ratio which contains, besides the common long-range-order term ∼ m 2 (the square of uniform magnetization), a term by correlations between magnetic granules. The obtained peculiar structure of the distribution function in the reciprocal space underlines the specifics of transport processes in such a system, compared to the known behavior of uniform metals.