Spin Injection and Detection in a Mesoscopic Superconductor at Low Temperatures

Abstract

We theoretically study nonequilibrium spin transport in a superconducting wire connected by tunnel junctions to two ferromagnetic metal wires, each of which serves as an injector or detector of spin-polarized electron current. We present a set of Boltzmann equations to determine nonequilibrium quasiparticle distributions in this system, and obtain an analytical expression for the nonlocal spin signal in the case of small injection current. It is shown that the quasiparticle distribution in the ferromagnetic metal for detection strongly affects the magnitude of the spin signal. At low temperatures, since nonequilibrium quasiparticles created by the tunneling from the superconductor dominate thermally excited ones, the spin signal becomes independent of temperature. This explains the convergence of the spin signal with decreasing temperature observed in a recent experiment by Poli \textit{et al}.

7 pages, 1 figure

References in corpus (8)

• Spin Injection and Detection in Magnetic Nanostructures
• Spin injection and relaxation in a mesoscopic superconductor
• Spin Transport in Diffusive Superconductors
• Spin transport and magnetoresistance in F/S/F spin valves
• Enhanced spin accumulation in a superconductor
• Spin relaxation in mesoscopic superconducting Al wires
• Boltzmann Equations for Spin and Charge Relaxations in Superconductors
• Influence of Charge and Energy Imbalances on the Tunneling Current through a Superconductor-Normal Metal Junction