High-Resolution Transmission Electron Microscopy of Defects in YBa2Cu4O8

Abstract
Microscopic structures of the high-T c superconductor YBa2Cu4O8 (T c=80 K) are examined by high-resolution transmission electron microscopy. Planar defects are observed as white spot lines in the micrograph of the single-phase YBa2Cu4O8 and they have a structure with an absence of one Cu-O chain in the double Cu-O chain of YBa2Cu4O8. YBa2Cu3O7 and Y2Ba4Cu7O15-like local structures exist around the planar defects.