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Published on: May 29, 2018
Field evaporation behavior in [0 0 1] FePt thin films
K L Torres1, B Geiser, M P Moody
1Department of Metallurgical and Materials Engineering, University of Alabama, College of Engineering, Tuscaloosa, AL 3548, USA.
Ultramicroscopy
|January 14, 2011
Summary
Atom probe tomography struggles with materials like L1(0) FePt due to differing elemental evaporation fields. This study quantifies reconstruction artifacts, revealing Fe depletion at poles caused by local magnification and electrostatic effects.
Area of Science:
- Materials Science
- Surface Science
- Analytical Chemistry
Background:
- Atom probe tomography (APT) relies on a hemispherical tip assumption for reconstruction, which can introduce artifacts.
- Significant differences in field evaporation fields between elements can exacerbate these reconstruction challenges.
- Understanding these artifacts is crucial for accurate chemical analysis in complex materials.
Purpose of the Study:
- To investigate the field evaporation behavior and reconstruction artifacts in the L1(0) FePt super-cell structure.
- To quantify the impact of differing elemental field strengths on APT data fidelity.
- To compare experimental findings with electrostatic simulation models.
Main Methods:
- Field evaporation experiments on L1(0) FePt with alternating Fe and Pt planes.
- Analysis of elemental composition and atom counts using APT.
- Comparison of experimental results with electrostatic simulation.
Main Results:
- Observed depletion of Fe at the (0 0 2) pole and zone axes in reconstructed APT data.
- Compositional profiles showed an increase in Fe and atom count away from the pole.
- Attributed Fe depletion to local magnification and electrostatic effects.
Conclusions:
- The basic hemispherical tip assumption in APT reconstruction is insufficient for materials with significant differences in elemental field strengths, such as L1(0) FePt.
- Local magnification and electrostatic effects are key factors causing reconstruction artifacts.
- Experimental validation against simulation models is essential for accurate interpretation of APT data in such systems.
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