Oxygen purity effect oxygen deficiency by argon heat treatment on Y:123 superconductors

Argon heat treatments at 450 °C for different times of 0, 12, 24, 36, 48 and 60 h on the two Y:123 oxygenated samples with different oxygen purity (Hp 99.99% and Lp 93%) are reported. The results of X-ray diffraction, oxygen deficiency and resistivity measurements are presented in details. Furthermore, the superconducting critical temperature Tc, normal resistivity ρ300, residual resistivity ρ0, resistivity slope dρ/dT and width of transition ΔTc are extracted from resistivity data. It is found that both c-parameter and oxygen deficiency increase by increasing annealing time, while OD and effective Cu valance decrease. But, the relative increase/decrease is more in Lp samples than that of Hp samples. Although Tc is decreased by annealing time for the two samples, the relative decrease in Tc is more in Lp samples when compared with those of Hp samples. Our results are discussed in terms of oxygen vacancies and hole carriers which are produced by annealing for the considered samples.