Crystal Structures of Tl-Ba-Ca-Cu-O Superconducting Phases Studied by High-Resolution Electron Microscopy

Abstract
Crystal structures of superconductors Tl2Ba2CaCu2O8 and Tl2Ba2Ca2Cu3O10, which show zero-resistivity at temperatures of 98 and 114 K, respectively, were studied with a high-resolution electron microscope having a resolution of 0.17 nm. High-resolution images clearly revealed arrangements of cations and oxygen vacancies in the superconductors. Computer image simulations provided evidence that a considerable amount of Tl atoms are substituted by Ca atoms.