Synthesis of PrBa₂Cu₄O₈ at ambient oxygen pressure

We report for the first time the successful synthesis of polycrystalline PrBa₂Cu₄O₈ (Pr124) at ambient oxygen pressure. Pr124 has been prepared by nitric pyrolysis and oxalate coprecipitation methods, and both methods yield qualitatively the same results. Powder X-ray-diffraction patterns of samples prepared by both methods show a nearly single "124" phase. Thermogravimetric analysis indicates no oxygen loss until the temperature is higher than 800°C, revealing that its thermal stability is distinct from that of PrBa₂Cu₃O₇. Electrical resistivity ρ(T) shows metallic behavior at low temperatures. These results show that the quality of the samples prepared at ambient oxygen pressure is comparable to that by hot isostatic pressing technique.