Effect of LiF addition on the formation of the superconducting YBa2Cu4O8 phase

Abstract

Several possible flux materials have been investigated for preparing the superconducting YBa₂Cu₄O₈ phase under 1 atm of oxygen. LiF was a promising flux and the YBa₂Cu₄O₈ phase was successfully obtained at 815 °C with 0.5–1.0 wt.% LiF. Large amounts of LiF (>1.0 wt.%) accelerated the formation of side products, i.e. BaCuO₂ and Y₂BaCuO₅, instead of the superconducting phase. LiF was also used as a flux in the syntheses of the superconducting Y_0.9Ca_0.1Ba₂Cu₄O₈ and EuBa₂Cu₄O₈ phases, and synthesis conditions for these compounds were optimized.