Long-range spin-polarized quasiparticle transport in mesoscopic Al   superconductors with a Zeeman splitting
  We report on nonlocal transport in multiterminal superconductor-ferromagnet structures, which were fabricated by means of e-beam lithography and shadow evaporation techniques. In the presence of a significant Zeeman splitting of the quasiparticle states, we find signatures of spin transport over distances of several {\mu}m, exceeding other length scales such as the coherence length, the normal-state spin-diffusion length, and the charge-imbalance length. The relaxation length of the spin signal shows a nearly linear increase with magnetic field, hinting at a freeze-out of relaxation by the Zeeman splitting. We propose that the relaxation length is given by the recombination length of the quasiparticles rather than a renormalized spin-diffusion length. 
F. H\"ubler, M. J. Wolf, D. Beckmann and H. V. L\"ohneysen
cond-mat.supr-con cond-mat.mes-hall