Microstructural Studies of Pb sub 2 Sr sub 2 ACu sub 3 O sub 8 Superconductors
20 March 1989
A detailed study of the microstructure of the new Pb sub 2 Sr sub 2 ACu sub 3 O sub 8 class of high temperature superconductors by Transmission Electron Microscopy (TEM) and electron diffraction is reported. For A = Dy + Sr, a 'supercell' is observed along the [100] and [110] directions, with a period three times the perovskite unit cell. Additional structural and superstructural variants with modulation vectors parallel to a and b have been observed in some fraction of the materials A = Eu + Sr, Dy + Ca, and Dy + Sr. High resolution images of the perovskite structure have been recorded and compared with calculated images.