| mportant features of the internal chemistry, such as solid solution behavior, stable defect species, and oxidation behavior, have been investigated by structural and physical property measurements of pure perovskite layered cuprates, and related to the inner architecture these potential superconductors. In-situ high temperature (650-800;Transitions from dual carrier (intrinsic) semiconductivity to extrinsic p-type semiconductivity, as a function of chemical composition, temperature, and oxygen pressure, are observed in the double-copper layer systems. Design of materials with high potential for superconductivity has been achieved by rational chemical variations in the inner architecture. The exclusion of interstitial oxygen defects between the copper-oxygen double layers, as evidenced in the weak oxygen partial pressure dependence of the electrical properties in the ;Jonker analysis of the electrical properties of these materials illustrates the similarity of the transport behavior of the quadruple perovskites to superconducting cuprates. The... |
