Magneto shot noise in noncollinear diffusive spin-valves

Abstract

We develop a semiclassical Boltzmann-Langevin theory of the spin polarized shot noise in a diffusive normal metal spin-valve connected by tunnel contacts to ferromagnetic reservoirs with noncollinear magnetizations. We obtain basic equations for correlations of the fluctuating spin-charge distribution and current density matrices by taking into account the spin-flip processes and precession of the spin accumulation vector in the normal metal. Applying the developed theory to a two terminal FNF structure, we find that for a small spin-flip strength and a substantial polarization of the terminals the shot noise has a nonmonotonic variation with the angle between magnetization vectors. While the shot noise is almost unchanged from the normal structure value for parallel configuration and increases well above the normal value for antiparallel configuration, it suppresses substantially at an intermediate angle depending on the ratio of the conductances of the N metal and the tunnel contacts. We also demonstrated pronounced effects of the polarization and the spin-flip scattering on the shot noise which reveals the interplay between relaxation and precession of the spin accumulation vector in the N metal.