Pinning and the mixed-state thermomagnetic transport properties of YBa2Cu3O7-delta

We have studied the role of pinning in the mixed-state thermomagnetic transport properties of YBa(2)Cu3O(7-delta). We demonstrate the pinning independence of the transport entropy S-phi, and its consequent scaling within an anisotropic mass model. Due to the anisotropy of YBa2Cu3O7-delta the extrinsic pinning strength effectively decreases as we rotate the magnetic field into the ab plane, The Nernst (E(y)/del(x)T) and Seebeck (E(x)/del(x)T) effects are enhanced as we reduce the effective pinning, yet the transport entropy S(phi)proportional to(E(y)/del(x)T)/rho(xx), the ratio of the Nernst and Seebeck signals, and the ratio of Seebeck and longitudinal resistivity rho(xx) are unchanged, similar to the pinning independence observed for the Hall conductivity sigma(xy). These results can be explained within a simple phenomenological model of vortex dynamics.