Large thermoelectric spin-valve effect with a superconductor

• DOI: 10.48550/arxiv.2502.06962
• Publication Date: 2025-02-10
• Authors: Pablo Tuero; Johanne Bratland ...; Carlos Sánchez; César González‐Ruano; Yuan Lu; Jacob Linder; F. G. Aliev
• Keywords: Spin valve

Recent studies have revealed magnetically controllable thermoelectric effects in superconductor/ferromagnet (S/F) structures. A tunable cryogenic generator needs not only a high conversion factor between electricity and heat, but also large change the output when switching magnetic state of device. Here, we experimentally measure numerically model fully epitaxial F/S/F junctions based on commercially available, easily grown materials, as well their dependence configuration F electrodes. We observe sizeable Seebeck coefficients for parallel alignment ferromagnetic electrodes, reaching values about $100$~$\mu$V/K. Importantly, find decrease signal more than an order magnitude from to antiparallel configuration, constituting spin-valve effect. Theoretical modeling self-consistent non-equilibrium Keldysh-Usadel Green function theory, combined with micromagnetic simulations, qualitatively reproduce experimental findings. These findings pave way development efficient versatile heat engines.