| 摘要 |
Compositions having the formula A1+/-xM2+/-xCu3Oy, wherein A is Y, or a combination of Y La, Lu, Sc or Yb; M is Ba, or a combination of Ba, Sr or Ca and y is sufficient to satisfy the valence demands, have been found to be bulk electrical superconductors at a temperature above 77K. The compositions are single phase perovskite-like crystalline structures. They are made by a process involving intimately mixing the metal oxides or their precursors in the proper molar ratios, heating the mixture in the presence of oxygen to a temperature between about 800 DEG C and about 1100 DEG C and slowly cooling the mixture to room temperature in the presence of oxygen over a period of at least four hours. |
