Some properties of bulk Y‐Ba‐Cu‐O compounds containing SiO2

摘要

Bulk Y‐Ba‐Cu‐O samples containing Si with nominal compositions of Y:Ba:Cu:Si=1:2:3:x(x=0.2, 0.4, and 0.6) have been prepared by adding SiO2to the source materials. After a relatively short heat treatment, the resistance transition characteristics of the samples were found to improve as the SiO2content was increased. Results from ac susceptibility measurements also showed improved values as the SiO2content was increased. However, as the solid‐state reaction was carried out at a lower temperature but for a longer time, the sample resistance increased and the superconductivity was found to degrade.