  We theoretically analyze non-local effects in electron transport across
three-terminal ballistic normal-superconducting-normal (NSN) structures with
spin-active interfaces. Subgap electrons entering S-electrode from one N-metal
may form Cooper pairs with their counterparts penetrating from another N-metal.
This phenomenon of crossed Andreev reflection is highly sensitive to electron
spins and yields a rich variety of properties of non-local conductance which we
describe non-perturbatively at arbitrary interface transmissions, voltages and
temperatures. Our results can be applied to hybrid structures with normal,
ferromagnetic and half-metallic electrodes and can be directly tested in future
experiments.
