Also, superconducting ceramics for use in accordance with the present invention may be prepared consistent with the stoichiometric formulae (A1-x Bx)y Cuz Ow, where A is one or more elements of Group Vb of the Priodic Table such as Bi, Sb and As, B is one or more elements of Group IIa of the Periodic Table, e.g., the alkaline earth metals including beryllium and magnesium, and x=0.3-1; y=2.0-4.0,