Analysis of Three-dimensional Atom-probe Data by the Proximity Histogram

TLDR

The 3‑D atom‑probe technique reconstructs elemental identities and 3‑D positions of up to ~1 million atoms from a sharply pointed specimen, yielding an analysis volume of roughly 20 × 20 × 200 nm³. This article proposes a data‑compilation method to generate composition profiles in the vicinity of interfaces in a geometrically independent manner. The method aggregates atom‑probe data to produce interface‑centric composition profiles regardless of interface geometry. Applying the method to a MgO/Cu(Ag) heterophase interface quantifies silver segregation and provides atom‑by‑atom chemical descriptions of crystallographic defects.

Abstract

Abstract The three-dimensional (3D) atom-probe technique produces a reconstruction of the elemental chemical identities and three-dimensional positions of atoms field evaporated from a sharply pointed metal specimen, with a local radius of curvature of less than 50 nm. The number of atoms collected can be on the order of one million, representing an analysis volume of approximately 20 nm × 20 nm × 200 nm (80,000 nm 3 ). This large amount of data allows for the identification of microstructural features in a sample, such as grain or heterophase boundaries, if the feature density is large enough. Correlation of the measured atomic positions with these identified features results in an atom-by-atom description of the chemical environment of crystallographic defects. This article outlines a data compilation technique for the generation of composition profiles in the vicinity of interfaces in a geometrically independent way. This approach is applied to quantitative determination of interfacial segregation of silver at a MgO/Cu(Ag) heterophase interface.