Explanation of high-temperature superconductivity without cuprate planes

Abstract The superconducting hole condensate resides in the SrO planes, or in the BaO planes, or in the interstitial regions of high-temperature perovskite superconductors, depending upon the crystal structure. Supporting evidence includes the following: firstly, PrBa2Cu3O7 superconducts in its BaO layers, and not in its cuprate planes; secondly, the similarity of the layer charges for YBa2Cu3Ox and PrBa2Cu3Ox indicates that both materials superconduct in their BaO layers; thirdly, Gd2-zCezSr2Cu2TiO10, Pr2-zCezSr2Cu2NbO10 and Eu2-zCezSr2Cu2TiO10 all superconduct in their SrO layers, and not in their cuprate planes; and fourthly, the superconducting hole condensate for Cu-doped Sr2YRuO6 (a material with no cuprate planes to better than 1%) must reside in its SrO layers.