Silver Substitution in Pb sub 2 Sr sub 2 Y sub (1-y) Ca sub y Cu sub 3 O sub 8 (y=O, 0.25).

Substitution of Ag for Cu in the the layered cuprate non-superconducting Pb sub 2 Sr sub 2 YCu sub 3 O sub 8 enabled phases of composition Pb sub 2 Sr sub 2 YCu sub (3-x) Ag sub x O sub 8 (x=0.55) to be prepared at 860C in air. X-ray powder crystallography showed that the Ag substitutes for the linearly coordinated Cu(1) atoms in the Pb sub 2 Sr sub 2 YCu sub 3 O sub 8 structure. Small amounts of Ag/Cu substitution could also be achieved in the superconducting phase Pb sub 2 Sr sub 2 Y sub (0.75) Ca sub (0.25) Cu sub 3 O sub 8 with little effect on its superconducting properties.