Hall Anomaly and Vortex-Lattice Melting in Superconducting Single Crystal YBa2Cu3O7-d

TL;DR

This study measures voltages in a pure YBa2Cu3O7-d superconductor to observe the Hall anomaly and vortex-lattice melting, revealing their correlation and effects on vortex dynamics and Hall conductivity.

Contribution

It provides the first simultaneous observation of the Hall anomaly and vortex-lattice melting transition in a single crystal superconductor.

Findings

Hall anomaly observed at vortex melting transition

Hall conductivity sharply decreases to large negative values

Vortex dynamics change significantly at melting point

Abstract

Sub-nanovolt resolution longitudinal and Hall voltages are measured in an ultra pure YBa2Cu3O7-d single crystal. The Hall anomaly and the first-order vortex-lattice melting transition are observed simultaneously. Changes in the dynamic behavior of the vortex solid and liquid are correlated with features of the Hall conductivity sxy. With the magnetic field oriented at an angle from the twin-boundaries, the Hall conductivity sharply decreases toward large negative values at the vortex-lattice melting transition.