Superconductivity in the system (AlxY1−x)Ba2Cu3O6.5+δ

Abstract

High-temperature superconductivity was observed in the system $\left({\mathrm{Al}}_x{\mathrm{Y}}_{1-x}\right){\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{6.5+\delta }$ for $0\le x\le 0.85$. Transition temperatures at zero resistance vary between 90.6 and 50 K, and are related to gradual crystal lattice changes. At $x=0.90\mathrm{}$ a time- and current-dependent resistance is found for $T<\mathrm{}25\mathrm{}$ K.