Crystal Structure of a New Phase in the Sr-Y-Cu-O System

A study of the Sr-Y-Cu-O system has yielded a new phase with an extended stoichiometry range. In contrast to other earth-alkaline/rare-earth cuprates, this phase is copper rich, similar to CaCu sub 2 O sub 3. Stoichiometries observed range from (Sr,Y) sub 4 Cu sub 7 O sub x to (Sr,Y) sub 3 Cu sub 5 O sub x.