Two types of twin boundaries in superconductor Y0.6Na0.4Ba2Cu2.7Zn0.3O7-δ, the

cation-centered and oxygen-centered types, and the associated twinning dislocation

were studied by high-resolution electron microscopy. The structure map projected

in the [001] direction was obtained from a single image by means of the image

deconvolution technique. In this map, all columns of metallic atoms appeared as

individual black dots, and hence the two types of twin boundaries were

distinguished from each other at atomic level. It was seen that the twinning

dislocation occurred when the two types of twin boundaries meet each other. The

structure model of the twinning dislocation together with the two types of twin

boundaries was derived straightforwardly based on the positions of black dots seen

in the deconvoluted image.

Atomic Configurations of Twin Boundaries and Twinning Dislocation in

Superconductor Y0.6Na0.4Ba2Cu2.7Zn0.3O7-δ. Y.M.Wang, W.Wan, R.Wang, F.H.Li,

G.C.Che: Philosophical Magazine Letters, 2008, 88[7] 481-9