  We report on the experimental observation of thermoelectric currents in
superconductor-ferromagnet tunnel junctions in high magnetic fields. The
thermoelectric signals are due to a spin-dependent lifting of particle-hole
symmetry, and are found to be in excellent agreement with recent theoretical
predictions. The maximum Seebeck coefficient inferred from the data is about
$-100~\mathrm{\mu V/K}$, much larger than commonly found in metallic
structures. Our results directly prove the coupling of spin and heat transport
in high-field superconductors.
