2009/01/26 by Yositake Takane
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1143/jpsj.78.024705
published as J. Phys. Soc. Jpn. 78 (2009) 024705 · 7 pages, 1 figure
openalex publication_date 2009/01/26 · arxiv created 2009/02/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 et al.