Transport coefficients and flux motion in Bi2Sr2CaCu2Ox single crystals

We present measurements of the electrical resistivity, thermal conductivity, and Hall, Nernst, and Seebeck effects in the mixed state of single crystalline Bi₂Sr₂CaCu₂O_x. It is shown that the sign of the Hall voltage changes twice as temperature decreases below T_c. From the Nernst effect we estimate the transport entropy S_φ to be about 10⁻¹⁰ erg/K cm. S_φ is equal to zero in the normal state, increases and passes through a maximum at the mixed state as expected. The temperature dependences of the thermoelectric power in magnetic fields are analogous to the resistive transition curves. These phenomena are discussed in terms of flux flow. The contribution of the flux flow to the thermal conductivity is estimated to be negligible. Lowering of the thermal conductivity at temperatures below T_c by a magnetic field is attributed to phonon scattering by the vortex lines.