Synthesis of a bulk YBa2Cu4O8 superconductor by addition of Ag2O at an ordinary pressure of oxygen

Abstract

The superconducting bulk YBa₂Cu₄O₈ compound has been successfully synthesized by the addition of Ag₂O as a reaction‐rate enhancer at an ordinary pressure of oxygen. An almost single YBa₂Cu₄O₈ phase together with the compositionally reasonable metallic silver phase could be formed when the added amount of Ag₂O was larger than 30 wt. %. The obtained bulk YBa₂Cu₄O₈ compound showed a T_c(zero) of 70 K in resistivity curve and a T_c(onset) of 80 K in alternating‐current magnetic susceptibility curve. The results well evidenced that the YBa₂Cu₄O₈ can be directly prepared by the conventional solid‐state reaction.