Thermomagnetic Effects in the Mixed State of Type II Superconductors

Abstract

A phenomenological theory is developed for the thermomagnetic effects in the flux flow state of type II superconductors. Ettinghausen-, Nernst-, and Righi-Leduc-coefficients are expressed explicitly with the use of known physical quantities. Thermal conductivity and analogous Peltier coefficient due to flux line are discussed in detail using a quasi-particle model for the flux line. It is shown that the analogous thermoelectric figure of merit in the flux flow states has large values of the order of 1/T in the perpendicular direction to the external electric current, while it is of the order of 10^-2/T∼10^-3/T in the direction parallel to the current. A possibility of a negative figure of merit is also pointed out.