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Title: The mystery of missing species in atom probe tomography of composite materials

There is a serious problem in atom probe tomography of composite materials such as oxides that even from stoichiometric samples one observes non-stoichiometric ion yields. We present a quantitative model that explains the non-stoichiometry allowing a fit to experimental data of ion yields as a function of applied field to extract activation barriers and prefactors. The numbers are confirmed by density functional theory. We also show that for oxides the missing oxygen is thermally desorbed as neutral O{sub 2}, either directly or associatively. Finally, we suggest methods to improve the experimental setup.
Authors:
; ;  [1]
  1. Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada)
Publication Date:
OSTI Identifier:
22489087
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; COMPOSITE MATERIALS; DENSITY FUNCTIONAL METHOD; DIFFUSION BARRIERS; OXIDES; OXYGEN; PROBES; STOICHIOMETRY; TOMOGRAPHY