Sign reversal of the Hall resistance in the mixed-state of La$_{1.89}$ Ce$_{0.11}$CuO$_{4}$ and La$_{1.89}$Ce$_{0.11}$(Cu$_{0.99}$Co$_{0.01}$)O$_{4} $ thin films

TL;DR

This study investigates the Hall resistance behavior in LaCeCuO thin films, revealing a double sign reversal in Co-doped samples linked to vortex pinning and impurity effects, aligning with theoretical predictions.

Contribution

It demonstrates the occurrence of double Hall sign reversal in Co-doped LaCeCuO thin films and links this phenomenon to vortex pinning and impurity effects, providing new experimental insights.

Findings

Double sign reversal observed in LCCO:Co films

Transition from strong to weak pinning correlates with Hall sign changes

Sign reversal behavior influenced by magnetic impurities and vortex coupling

Abstract

The transport properties of La$_{1.89}$Ce$_{0.11}$CuO$_{4}$(LCCO) and La$_{1.89}$Ce$_{0.11}$(Cu$_{0.99}$Co$_{0.01}$)O$_{4}$ (LCCO:Co) superconducting thin films are investigated. When the external field $\bf H$ is applied along the crystallographic c-axis, a double sign reversal of the Hall voltage in the mixed state of LCCO:Co thin films is observed whereas a single sign reversal is detected in LCCO. A double sign reversal of the Hall signal in LCCO can be recovered if the magnetic field is tilted away from the plane of the film. We find that the transition from one to two of the Hall sign reversal coincides with the change in the pinning from strong to weak. This temperature/field induced transition is caused either by the magnetic impurities in LCCO:Co or by the coupling between the pancake vortices and the in-plane Josephson vortices in LCCO. These results are in agreement with early theoretical and numerical predictions.