Enhancement of thermoelectric effect in diffusive superconducting bilayers with magnetic interfaces

We demonstrate that thermoelectric currents in superconducting bilayers with a spin-active interface are controlled by the two competing processes. On one hand, spin-sensitive quasiparticle scattering at such an interface generates an electron-hole imbalance and yields an orders-of-magnitude enhancement of the thermoelectric effect in the system. On the other hand, this electron-hole imbalance gets suppressed in the superconductor bulk due to electron scattering on nonmagnetic impurities. As a result, large thermoelectric currents can only flow in the vicinity of the spin-active interface and decay away from this interface at a distance exceeding the electron elastic mean free path [scriptl]. The magnitude of the thermoelectric effect reaches its maximum provided [scriptl] becomes of order of the total bilayer thickness.