A theory of spin-dependent ballistic transport in the effective-mass approximation

A unified theory describing a spin-dependent transport of electrons through a thin metallic or insulator nonmagnetic layer sandwiched between two ferromagnets is developed in the ballistic regime and current-perpendicular-to-plane (CPP) geometry. The theory is based on the Landauer formalism and the exact electron transmission coefficient in the effective-mass approximation. Results of numerical calculations are presented.