Preparation of YBa2Cu4O8 superconductor from oxalate precursor under ambient pressure

The YBa2Cu4O8, 124, superconductor was prepared from the coprecipitated oxalate precursor powder. Almost complete (>99.9%) precipitation of the cations as oxalates is achieved from concentrated acetic acid medium. Firing at 780°C under atmospheric oxygen pressure yielded pure phase YBa2Cu4O8 superconducting material with Tc ∼ 81 K. This material is quite stable upto 840°C. Further firig at 860°C it transforms to...