The structure of an AI3Pd-based modulated structure studied by atomic-scale electron microscopy observations

A modulated structure based on an Al3Pd structure in an Al70Co25Pd5 alloy has been studied by atomic-scale observations with high-resolution transmission electron microscopy (HREM) and high-angle annular detector dark-field (HAADF) technique using a scanning transmission electron microscope. From the electron microscopy observations, we can reveal an arrangement of atom columnar clusters, which produces peculiar shifts of diffraction spots in an electron diffraction pattern. Arrangements of transition-metal atoms in defect regions in the modulated structure are proposed from the observed HAADF image.