Hall Anomaly Near T_c in YBa₂Cu₃O_7-δ: Effects of Renormalized Superconducting Fluctuations and Pinning

The Hall effect in epitaxial YBa₂Cu₃O_7-x films in perpendicularly applied magnetic fields B from 1 to 6 T reveals a sign reversal of the Hall coefficient for B ≤ 3 T. We analyze our experimental data by using the full quantitative expressions based on the renormalized superconducting fluctuation model. We propose an approach how the vortex pinning can be considered in the Hall coefficient, based on the observation that flux pinning mainly affects the longitudinal conductivity in the low-temperature part of the superconducting transition.