Structural characterization of Ba₂YCu₃O₇ by high resolution transmission electron microscopy

We show that high‐resolution transmission electron microscopy can be used directly to reveal the structure of the metal framework and its defects in Ba₂YCu₃O₇. The use of dynamical effects under carefully selected and controlled conditions allows the detection of long‐range order in the disposition of the oxygen vacancies, but inevitable misalignments make the quantification of the order parameter difficult. Specimen preparation methods are compared, and a wide‐angle convergent‐beam pattern is demonstrated.