Hall effect anomaly near Tc and renormalized superconducting fluctuations in YBCO

TL;DR

This study investigates the Hall effect anomaly near the critical temperature in YBCO superconductors, demonstrating how renormalized fluctuations and inhomogeneity influence the Hall coefficient and proposing a model that includes vortex pinning effects.

Contribution

It introduces a comprehensive model incorporating renormalized superconducting fluctuations and inhomogeneity to explain the Hall effect anomaly in YBCO near Tc.

Findings

Sign reversal of the Hall coefficient observed at low magnetic fields.

The renormalized fluctuation model explains the experimental data near Tc.

Vortex pinning effects significantly impact the Hall coefficient.

Abstract

Measurements of the Hall effect and the resistivity on precisely-patterned YBCO thin films in magnetic fields B from 0.5 to 6 T oriented parallel to the sample crystallographic c axis reveal a sign reversal of the Hall coefficient for B <= 3 T. The data are compared to the full, quantitative expressions based on the renormalized fluctuation model for the Hall conductivity. The model offers a satisfactory understanding of the experimental results, for moderate fields and temperatures near the critical region, provided that the inhomogeneity of the critical temperature distribution is also taken into account. We also propose an approach how vortex pinning that strongly affects the magnitude of the Hall coefficient can be incorporated in the model.