(color online) 3D reconstruction of a FePt nanoparticle including 3D atomic positions, elemental identification, and detailed grain structure. (a) The 3D positions of individual atoms of Fe and Pt. (b) Multislice images through the reconstructed 3D atomic model along the [100], [010], and [001] directions. Color bars indicate the degree of ordering, varying between pure L1₂/L1₀ and chemically disordered fcc. Scale bar, 2 nm. (c) The nanoparticle consists of two large L1₂ grains, three small L1₂ grains, three small L1₀ grains and a Pt-rich A1 grain.^[50]