Ambient pressure synthesis of Pr124 and Pr247 using citrate pyrolysis precursor method

Practical synthetic conditions of PrBa2Cu4O8 (Pr124) and Pr2Ba4Cu7O15−δ (Pr247) were clarified for our citrate pyrolysis precursor method. The decided optimum calcination temperatures were 875–880 °C for Pr124 and 885 ± 0.5 °C for Pr247. Calcination time at least ∼80 h is necessary for both the syntheses of Pr124 and Pr247, and further duration is effective in avoiding impureness by PrBaO3 for Pr124 synthesis. Especially for the case of Pr247, the allowed temperature condition is very tight considering inevitable temperature graduation in an ordinary electric furnace. So further experimental devising for temperature homogeneity must be necessary to obtain single phase Pr247. Basically, however, it was confirmed that Pr124 and Pr247 can form under ambient pressure condition with our synthetic method consistently.