Incommensurate Modulated Structure of “Pb”-1223 Determined by Combining High Resolution Electron Microscopy and Electron Diffraction

Abstract

The one-dimensional incommensurate modulated structure of (Pb_0.5Sr_0.3Cu_0.2)Sr₂(Ca_0.6Sr_0.4)₂Cu₃O_y has been determined. The low-resolution average structure was derived by image deconvolution. The image resolution was enhanced by phase extension based on a set of corrected electron diffraction intensities. Multi-dimensional direct methods were then used to solve the four-dimensional (4D) structure. The incommensurate modulated structure was finally obtained by cutting the 4D structure with the three-dimensional physical space. Occupation and/or displacement modulation has been observed for all atoms.