The influence of Ag on univariant reactions and the oxygen content of the eutectic melt in the Y–Ba–Cu–(Ag)–O system

In situstudy through electrical resistance of growth rate of trifluoroacetate-based solution-derived YBa2Cu3O7films

“…This equation allows to propose that, as a validity test of our assumption that the term C(T) is the dominant one, we need only to look at the plot lnG vs 1/T, which should follow a straight line if the other temperature-dependent terms included in equation ( 8) have a smoother dependence. As is shown in figure 5(b), the predicted law (equation ( 8)) properly describes the observed experimental temperature dependence G(T) and so we can indeed estimate the formation enthalpy of the YBCO formation reaction, Δ Θ H ∼ 190 kJ mol −1 F, as well as that of the YBCO-Ag phase Δ Θ H ∼ 212 kJ mol −1 F. Our results suggest, therefore, that both the increase of the growth rate of YBCO-Ag films and the enhanced tendency to nucleate c-axis islands previously reported [29] have a common thermodynamic origin, leading also to a decrease in the peritectic temperature of the YBCO-Ag system [12,29,63,64]. These are features which may have consequences in the processing of YBCO CCs and are certainly worthy of further investigation.…”

Morphology and composition changes of the Pt-based secondary phase in melt-grown YBCO caused by Al pollution

“…In the samples with Ag addition, only Pt-based particles of irregular shapes were observed and they did not contain any Al (figure 5 the sample, the solidified Ag inclusions were found to contain Al between 0.1 and 0.6 wt%. This result indicates that, in addition, the diffusion of Al into the melt is significantly hindered by trapping aluminium in the silver-rich melt which appears during the melt process [11].…”

Growth, nanostructure and vortex pinning in superconducting YBa2Cu3O7thin films based on trifluoroacetate solutions

“…It is remarkable, however, that no modification of T c is observed, an issue that was associated with Ag sublimation at the growth temperature [36]. The influence of Ag additives on the stability of c-axis nucleation can be understood if we take into account that supersaturation µ is decreased because the peritectic temperature of the Ag-Y-Ba-Cu-O system is decreased [36,112,113], similarly to REBCO oxides with high RE atomic number. As a consequence, the crossover temperature where c-axis nucleation becomes dominant (figure 16) is decreased, similarly to YbBCO films [99].…”