  Nonequilibrium charge transport in superconductors has been investigated
intensely in the 1970s and 80s, mostly in the vicinity of the critical
temperature. Much less attention has been focussed on low temperatures, and the
role of the quasiparticle spin. We report here on nonlocal transport in
superconductor hybrid structures at very low temperatures. By comparing the
nonlocal conductance obtained using ferromagnetic and normal-metal detectors,
we discriminate charge and spin degrees of freedom. We observe spin injection
and long-range transport of pure, chargeless spin currents in the regime of
large Zeeman splitting. We elucidate charge and spin tranport by comparison to
theoretical models. The observed long-range chargeless spin transport opens a
new path to manipulate and utilize the quasiparticle spin in superconductor
nanostructures.
