Thermomagnetic and Galvanomagnetic Effects in the Mixed State of High-T c Superconductors

We report on measurements of galvanomagnetic effects (electrical resistiviy, Hall effect) and thermomagnetic effects (thermopower, Nernst-effect) in the mixed state of high-Tc- superconductors. We discuss our results in terms of various possible dissipative mechanisms, since the occurence of a large thermopower, which can not be attributed to vortex motion, and also large dissipation in the force free configuration of the resistivity suggest that in addition to vortex motion also other dissipative channels (e.g. quasiparticle dynamics, fluctuations, granularity) are important.