Quantitative analysis of short-range order diffuse scattering in Cu-27.5 at%Pd alloy with energy-filtered electron diffraction

Diffuse scattering associated with a short-range ordered (SRO) state in a Cu-27.5 at%Pd alloy was quantitatively analyzed using energy-filtered transmission electron microscopy. By subtracting the background in electron diffraction with the energy filter, diffuse scattering splitting in two and fourfold was clearly observed at around 100, 110 and their equivalent positions in reciprocal space. Through the analysis of the electron diffraction patterns, it was clarified that the intensity distributions of the diffuse scattering did not change considerably with the crystal thickness, while those of the fundamental reflections remarkably changed. The intensity ratio of the total diffuse scattering to the total electron intensity increased monotonously with the increase of the crystal thickness. Based on these results, the two-dimensional SRO parameters of this alloy were quantitatively evaluated from the energy-filtered electron diffraction patterns.