Effect of Processing Parameters on the Superconductivity of HgO Added Y-123 Compound

Abstract

The superconducting properties of the Y-123 superconductors are very sensitive to the oxygen content and therefore requires oxygen annealing. Alternatively, the oxygen content can be optimized by using some material as an internal source of oxygen. The present study was undertaken to illuminate the effect of HgO addition in Y-123 superconductors, synthesized at different temperatures under variant conditions. Polycrystalline samples of Y-123 were synthesized with nominal composition YBa2Cu3O7 − x adding 30% weight of HgO. The X-ray diffraction patterns of all the samples revealed monophasic Y-123 nature without any trace of Hg. A sharp transition at 90 K was observed in the samples treated at 950°C, 960°C, and 975°C, although these were annealed without oxygen flow. The scanning electron micrographs of these samples showed uniform grain size with substantial grain interdiffusion. The significant role played by the HgO is to provide oxygen ambient through its decomposition. Thus, Y-123 samples with 90 K transition can be prepared without oxygen annealing.