Spin-drift transport and its applications

We study the generation of nonequilibrium spin currents in systems with spatially inhomogeneous magnetic potentials. For sufficiently high current densities, the spin polarization can be transported over distances significantly exceeding the intrinsic spin-diffusion length. This enables applications that would be impossible within the conventional spin-diffusion regime. Specifically, we propose dc measurement schemes for the carrier spin-relaxation times, $T_1$ and $T_2,$ as well as demonstrate the possibility of spin species separation by driving current through a region with an inhomogeneous magnetic potential.