Impact of oxygen annealing on the heat capacity and magnetic resonance of superconducting Pr0.88LaCe0.12CuO4-δ

We use thermodynamic and neutron-scattering measurements to study the effect of oxygen annealing on the superconductivity and magnetism in Pr0.88LaCe0.12CuO4-delta. Although the transition temperature T-c measured by susceptibility and superconducting coherence length increases 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 first be determined in order to establish a Ce doping dependence of antiferromagnetism and superconductivity phase diagram for electron-doped copper oxides.