  A pure spin current injector is proposed based on adiabatic pumping and
crossed normal/Andreev reflection. The device consists of a three-terminal
ferromagnet-superconductor-semiconductor system in which the injection of a
pure spin current is into the semiconductor which is coupled to the
superconductor within a coherence length away from the ferromagnet enabling the
phenomena of crossed normal /Andreev reflection to operate. Quantum pumping is
induced by adiabatically modulating two independent parameters of the
ferromagnetic lead, namely the magnetization strength and the strength of
coupling between the ferromagnet and the superconductor. The competition
between the normal/Andreev reflection and the crossed normal/Andreev
reflection, both induced by pumping, leads to non-local injection of a pure
spin current into the semiconductor. The experimental realization of the
proposed device is also discussed.
