Preparation of a 90 K Superconductor (LaBa2Cu3O7-y) with Ag-Related Additives

Abstract
The orthorhombic LaBa2Cu3O7-y compounds which show superconducting transitions over 90 K were synthesized with Ag-related additives by liquid phase sintering through the molten Ag. From the results of SEM coupled with X-ray microanalysis and X-ray photoemission, more than 90% of the Ag was incorporated as the metallic state in the grain boundaries. The superconducting volume fraction and critical current density were improved by the addition of Ag2O. Both of them had a maximum value at Ag2O contents, i.e. 12.5% to 25%.