Thermoelectric and thermomagnetic effects in the mixed state of HTSC's

Whereas flux line diffusion in the mixed state of HTSC's driven by the Lorentz force has been studied extensively, the thermal diffusion phenomena have received much less attention. In the mixed state, thermal diffusion of the quasiparticles and of the flux lines result in the Seebeck effect and the Nernst effect, respectively. Measurements of these effects yield the transport entropy of the diffusing species. We discuss the recent results obtained mostly for YBaCuO epitaxial films or single crystals, and emphasize the points where thermomagnetic experiments can discriminate between different models for dissipation.