Magneto shot noise in noncollinear diffusive spin-valves

TL;DR

This paper develops a semiclassical theory to analyze spin-polarized shot noise in diffusive spin-valves with noncollinear magnetizations, revealing how polarization, spin-flip scattering, and magnetization angles influence noise behavior.

Contribution

It introduces a new semiclassical Boltzmann-Langevin framework for spin shot noise in noncollinear spin-valves, accounting for spin-flip processes and spin precession effects.

Findings

Shot noise varies nonmonotonically with magnetization angle.

Parallel configuration yields noise similar to normal metal; antiparallel increases noise.

Polarization and spin-flip scattering significantly affect shot noise behavior.

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.