Effect of Annealing Conditions on the Tc of the Y2Ba4Cu7O15-x Superconductor

The superconductor Y2Ba4Cu7O15-x was prepared in bulk form, and the effect of annealing conditions on superconductivity was investigated by annealing under various conditions. Single-phase 247 samples were prepared at 870°C in 1 atm oxygen. The Tc was found to decrease from a maximum of 82 K for a sample quenched from 300°C to a minimum of 40 K for a sample quenched from 870°C.