Surface decomposition of Pb2Sr2(Ca,Y)Cu3O8+δ at room temperature studied with high-resolution electron microscopy

High-resolution electron microscopy shows that Pb2Sr2(Ca,Y)Cu3O8+δ is sensitive to air at room temperature. Planar defects are induced by exposure to air. These planar defects are due to a depletion of Pb and Cu from the three-layer block: PbO-Cu□-PbO, □ being a vacancy. Once these blocks are depleted, further depletion is enhanced, leading to almost completely depleted patches within these blocks and finally to the absence of several of the layers within this block. The new structures, thus formed, are potential new superconductors with high Tc's