Superconducting fluctuation in Hall and diagonal conductivities in YBa2Cu3O7-δ

Magnetic field dependence of Hall conductivity of YBa2Cu3O7-δ single crystal thin films are studied near above the mean field transition temperature Tc. Hall conductance deviates from an H-linear dependence. The deviation is attributed to the superconducting fluctuation effect and analyzed in terms of a theory considering the skew scattering effect, phenomenologically. Skew scattering life times are derived, which indicate that skew scattering plays an important role in the normal-state Hall effect. In Hall effects, the influence of the superconducting fluctuation(SF) has never been observed so far in ordinary superconductors. On the other hand, the Hall coefficient RH in most of the high Tc oxides in the normal state depends strongly on T. Although it is proposed that this anomalous T-dependence may be caused by magnetic skew scattering, the mechanism remains to be understood. The existence of the antiferromagnetic correlations of magnetic Cu ions in superconducting states of the present material suggests the presence of skew scattering. In this paper, the authors study the H-dependence of Hall conductivity σxy (H) near above Tc on high quality YBCO films. We find SF in σxy and analyze this in terms of the skew scattering theory. Skew scattering life times are derived and the T-dependence of Hall coefficient is discussed