Multiscale approach to spin transport in magnetic multilayers

This paper discusses two dual approaches to spin transport in magnetic multilayers: a direct, purely quantum, approach based on a tight-binding (TB) model and a semiclassical approach [continuous random matrix theory CRMT]. The combination of both approaches provides a systematic way to perform multiscale simulations of systems that contain relevant physics at scales larger (spin accumulation, spin diffusion) and smaller (specular reflexions, tunneling) than the elastic mean free paths of the layers. We show explicitly that CRMT and TB give consistent results in their common domain of applicability.