Destruction of Neel order and appearance of superconductivity in electron-doped cuprates by oxygen annealing process

TL;DR

This study investigates how oxygen annealing affects magnetism and superconductivity in electron-doped cuprates, revealing a sudden emergence of bulk superconductivity linked to oxygen removal, crucial for understanding phase diagrams.

Contribution

It demonstrates that oxygen annealing induces a sharp transition to bulk superconductivity and destroys Neel order in electron-doped cuprates, clarifying the phase diagram dependence.

Findings

Superconducting transition temperature increases smoothly with oxygen removal.

Bulk superconductivity appears abruptly near maximum $T_c$.

Neel order is destroyed as superconductivity emerges.

Abstract

We use thermodynamic and neutron scattering measurements to study the effect of oxygen annealing on the superconductivity and magnetism in Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-\delta}$. Although the transition temperature $T_c$ measured by susceptibility and superconducting coherence length increase smoothly with gradual oxygen removal from the annealing process, bulk superconductivity, marked by a specific heat anomaly at $T_c$ and the presence of a neutron magnetic resonance, only appears abruptly when $T_c$ is close to the largest value. These results suggest that the effect of oxygen annealing must be first determined in order to establish a Ce-doping dependence of antiferromagnetism and superconductivity phase diagram for electron-doped copper oxides.