Angle-dependence of the Hall effect in HgBa2CaCu2O6 thin films

TL;DR

This study investigates the angle-dependent Hall effect in HgBa2CaCu2O6 thin films, revealing a double sign change near the superconducting transition and analyzing it using a fluctuation model adapted for different magnetic field orientations.

Contribution

It provides new insights into the angle dependence of the Hall effect in high-temperature superconducting thin films and applies a modified fluctuation model to interpret the phenomena.

Findings

Observed double sign change of Hall coefficient near transition

Demonstrated angle dependence of the Hall effect in Hg-based superconductor

Applied a field rescaling procedure to model the Hall conductivity

Abstract

Superconducting compounds of the family Hg-Ba-Ca-Cu-O have been the subject of intense study since the current record-holder for the highest critical temperature of a superconductor belongs to this class of materials. Thin films of the compound with two adjacent copper-oxide layers and a critical temperature of about 120 K were prepared by a two-step process that consists of the pulsed-laser deposition of precursor films and the subsequent annealing in mercury-vapor atmosphere. Like some other high-temperature superconductors, Hg-Ba-Ca-Cu-O exhibits a specific anomaly of the Hall effect, a double-sign change of the Hall coefficient close to the superconducting transition. We have investigated this phenomenon by measurements of the Hall effect at different angles between the magnetic field direction and the crystallographic c-axis. The results concerning the upper part of the transition, where the first sign change occurs, are discussed in terms of the renormalized fluctuation model for the Hall conductivity, adapted through the field rescaling procedure in order to take into account the arbitrary orientation of the magnetic field.