TUNNELING, RELAXATION OF SPIN-POLARIZED QUASI-PARTICLES, AND SPIN-CHARGE SEPARATION IN SUPERCONDUCTORS

The nonequilibrium spin imbalance created when electrons tunnel from a ferromagnet to a superconductor is calculated. Since the charge curre nt in a superconductor is carried by the condensate within a penetrati on length of the surface and the spin current, which is carried by qua siparticles, can exist in the bulk, one may be able to directly demons trate spin-charge separation in a superconductor using spin injection techniques. After estimating the spin-relaxation rates due to magnetic impurity and spin-orbit scattering, an explicit experimental geometry for demonstration of spin-charge separation is discussed.