Superconducting ceramics for use in accordance with the present invention also may be prepared in consistence with the stoichiometric formulae (A1-x Bx)y Cuz Ow Xv, where A is one or more elements of Group IIIa of the Priodic Table, e.g., the rare earth elements, B is one or more elements of Group IIa of the Periodic Table, e.g., the alkaline earth metals including beryllium and magnesium, X is on