The structure of an Al3Pd-based modulated structure studied by atomic-scale electron microscopy observations

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