ChemInform Abstract: The Influence of Oxygen Variation on the Crystal Structure and Phase Composition of the Superconductor YBa2Cu3O7-x.
Abstract
In attempts to prepare a material with an O7.00 (x = 0 in the title compound) composition, the highest oxygen content achieved by annealing in an O2 stream at 440 °C for 24 h is 6.96 (iodometric determination).
ChemInform Abstract
In attempts to prepare a material with an O7.00 (x = 0 in the title compound) composition, the highest oxygen content achieved by annealing in an O2 stream at 440 °C for 24 h is 6.96 (iodometric determination). The orthorhombic phase is shown to exist over the composition range O6.96-O6.60 and the tetragonal phase (prepared in Ar or N2 at temp. at about 700 °C) exists from O6.0 to O6.15. Compositions with oxygen contents of 6.15-6.60 may be mixtures of these phases. A study of Tc as a function of x for YBa2Cu3O7-x shows a Tc of 90 K for a sample with x = 0.2 and 55 K for x = 0.4.
