title: Long-range spin-polarized quasiparticle transport in mesoscopic Al superconductors with a Zeeman splitting.
abstract: 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 μm, 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.
authors.affiliation: Institut für Nanotechnologie, Karlsruher Institut für Technologie, Karlsruhe, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Hübler
authors.forename: M J
authors.initials: MJ
authors.lastname: Wolf
authors.forename: D
authors.initials: D
authors.lastname: Beckmann
authors.forename: H
authors.initials: H
authors.lastname: V Löhneysen