Characterization of Pd and Pd@Au core-shell nanoparticles using atom probe tomography and field evaporation simulation

TL;DR

This study uses atom probe tomography and simulations to analyze Pd and Pd@Au nanoparticles in a Ni matrix, revealing how local field variations affect data accuracy and reconstruction quality.

Contribution

It provides a detailed comparison of experimental atom maps with simulations, highlighting the impact of local evaporation fields on nanoparticle analysis.

Findings

Good agreement between experiments and simulations for Pd and Ni evaporation fields.

Discrepancies in Au evaporation field predictions suggest limitations of the image hump model.

Local composition variations significantly influence atom probe tomography results.

Abstract

We report on atom probe tomography analyses of Pd and Pd@Au nanoparticles embedded in a Ni matrix and the effects of local evaporation field variations on the atom probe data. In order to assess the integrity of the reconstructed atom maps, we performed numerical simulations of the field evaporation processes and compared the simulated datasets with experimentally acquired data. The distortions seen in the atom maps for both Pd and Pd@Au nanoparticles could be mostly ascribed to local variations in chemical composition and elemental evaporation fields. The evaporation field values for Pd and Ni, taken from the image hump model and assumed in the simulations, yielded a good agreement between experimental and simulation results. In contrast, the evaporation field for Au, as predicted from the image hump model, appeared to be substantially overestimated and resulted in a large discrepancy between experiments and simulations.