Improvement of Water-Resistivity of High-T_c Superconductor by Ag₂O Addition

Abstract

The deterioration of superconductivity in YBCO system occurs rapidly by moisture adsorption. The addition of Ag₂ O into system improves water-resistivity of superconductivity. Appropriate amount of Ag₂ O and calcinated YBCO powder were mixed. The mixture was recalcinated, pulverized, pressed into pellets, and then sintered. Immersion of YBCO pellet, which contained no silver, into boiling water for one minute disappeared the superconductivity. By 5wt% and 10wt% addition of Ag₂ O to specimens, superconductivity retained even after the thirty minutes and one hour boiling water immersion, respectively. From the results of EPMA and X-ray diffraction pattern, it was suggested that silver deposited in crystallte surface prevents water diffusion into superconducting crystallites.