Spin-dependent Seebeck coefficients of Ni80Fe20 and Co in nanopillar spin valves

摘要: We have experimentally determined the spin-dependent Seebeck coefficient of permalloy (Ni${}_{80}$Fe${}_{20}$) and cobalt (Co) using nanopillar spin valve devices, a stack two ferromagnetic layers separated by nonmagnetic layer. The devices were specifically designed to separate heat-related effects from charge-related effects. A heat current, with no accompanying charge through leads thermovoltage proportional ${S}_{S}={S}_{\ensuremath{\uparrow}}\ensuremath{-}{S}_{\ensuremath{\downarrow}}$ ferromagnet, where ${S}_{\ensuremath{\uparrow}}$ ${S}_{\ensuremath{\downarrow}}$ are for spin-up spin-down electrons. By three-dimensional finite-element model based on thermoelectric theory, whose input material parameters measured in we able accurately determine $\ensuremath{-}$1.8 $\ensuremath{\mu}$V K${}^{\ensuremath{-}1}$ $\ensuremath{-}$4.5 permalloy, respectively, corresponding polarization ${P}_{S}={S}_{S}/{S}_{F}$ 0.08 0.25, ${S}_{F}$ is ferromagnet. results agreement earlier theoretical work Co/Cu multilayers Peltier measurements Ni${}_{80}$Fe${}_{20}$/Cu structures.