Interpreting Atom Probe Data from Oxide–Metal Interfaces

2018 ◽  
Vol 24 (4) ◽  
pp. 342-349 ◽  
Author(s):  
Ingrid McCarroll ◽  
Barbara Scherrer ◽  
Peter Felfer ◽  
Michael P. Moody ◽  
Julie M. Cairney
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale ◽  
Field Evaporation ◽  
Correlative Microscopy ◽  
Reconstruction Process ◽  
Simulation Techniques ◽  
Field Simulation ◽  
Metal Interfaces

AbstractUnderstanding oxide–metal interfaces is crucial to the advancement of materials and components for many industries, most notably for semiconductor devices and power generation. Atom probe tomography provides three-dimensional, atomic scale information about chemical composition, making it an excellent technique for interface analysis. However, difficulties arise when analyzing interfacial regions due to trajectory aberrations, such as local magnification, and reconstruction artifacts. Correlative microscopy and field simulation techniques have revealed that nonuniform evolution of the tip geometry, caused by heterogeneous field evaporation, is partly responsible for these artifacts. Here we attempt to understand these trajectory artifacts through a study of the local evaporation field conditions. With a better understanding of the local evaporation field, it may be possible to account for some of the local magnification effects during the reconstruction process, eliminating these artifacts before data analysis.

scholarly journals Atom Probe Analysis of Ex Situ Gas-Charged Stable Hydrides

2017 ◽  
Vol 23 (2) ◽  
pp. 307-313 ◽  
Author(s):  
Daniel Haley ◽  
Paul A. J. Bagot ◽  
Michael P. Moody
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale ◽  
Ex Situ ◽  
Native Oxide ◽  
Probe Analysis ◽  
Atom Probe Tomography Analysis ◽  
Hydrogen Analysis ◽  
Atom Probe Analysis

AbstractIn this work, we report on the atom probe tomography analysis of two metallic hydrides formed by pressurized charging using an ex situ hydrogen charging cell, in the pressure range of 200–500 kPa (2–5 bar). Specifically we report on the deuterium charging of Pd/Rh and V systems. Using this ex situ system, we demonstrate the successful loading and subsequent atom probe analysis of deuterium within a Pd/Rh alloy, and demonstrate that deuterium is likely present within the oxide–metal interface of a native oxide formed on vanadium. Through these experiments, we demonstrate the feasibility of ex situ hydrogen analysis for hydrides via atom probe tomography, and thus a practical route to three-dimensional imaging of hydrogen in hydrides at the atomic scale.

scholarly journals Reflections on the Spatial Performance of Atom Probe Tomography in the Analysis of Atomic Neighborhoods

2021 ◽  
pp. 1-11
Author(s):  
Baptiste Gault ◽  
Benjamin Klaes ◽  
Felipe F. Morgado ◽  
Christoph Freysoldt ◽  
Yue Li ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Atom Probe ◽  
Atomic Scale ◽  
High Entropy Alloys ◽  
Material System ◽  
Field Evaporation ◽  
Ion Imaging ◽  
High Entropy ◽  
Spatial Performance ◽  
Pure Metals

Atom probe tomography (APT) is often introduced as providing “atomic-scale” mapping of the composition of materials and as such is often exploited to analyze atomic neighborhoods within a material. Yet quantifying the actual spatial performance of the technique in a general case remains challenging, as it depends on the material system being investigated as well as on the specimen's geometry. Here, by using comparisons with field-ion microscopy experiments, field-ion imaging and field evaporation simulations, we provide the basis for a critical reflection on the spatial performance of APT in the analysis of pure metals, low alloyed systems and concentrated solid solutions (i.e., akin to high-entropy alloys). The spatial resolution imposes strong limitations on the possible interpretation of measured atomic neighborhoods, and directional neighborhood analyses restricted to the depth are expected to be more robust. We hope this work gets the community to reflect on its practices, in the same way, it got us to reflect on our work.

scholarly journals An atomic-scale view at the composition of amyloid-beta fibrils by atom probe tomography

2018 ◽  
Author(s):  
Kristiane A.K. Rusitzka ◽  
Leigh T. Stephenson ◽  
Agnieszka Szczepaniak ◽  
Lothar Gremer ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Atom Probe Tomography ◽  
Senile Plaques ◽  
Three Dimensional ◽  
Atom Probe ◽  
Pulse Frequency ◽  
Atomic Scale ◽  
Chemical Information ◽  
Protein Fibrils ◽  
Spectrometry Technique

ABSTRACTAmyloid-beta (Aβ) proteins play an important role in a number of neurodegenerative diseases. Aβ is found in senile plaques in brains of Alzeimer’s disease patients. The 42 residues of the monomer form dimers which stack to fibrils gaining several micrometers in length. Using Aβ fibrils with 13C and 15N marker substitution, we developed an innovative approach to obtain insights to structural and chemical information of the protein. We deposited the modified protein fibrils to pre-sharped aluminium needles with >100-nm apex diameters and, using the position-sensitive mass-to-charge spectrometry technique of atom probe tomography, we acquired the chemically-resolved three dimensional information for every detected ion evaporated in small fragments from the protein. We also discuss the influence of experimental parameters such as pulse energy and pulse frequency of the used Laser beam which lead to differences in the size of the gained fragments, developing the capability of localising metal atom within Aβ plaques.

A New Approach to the Determination of Concentration Profiles in Atom Probe Tomography

2012 ◽  
Vol 18 (2) ◽  
pp. 359-364 ◽  
Author(s):  
Peter J. Felfer ◽  
Baptiste Gault ◽  
Gang Sha ◽  
Leigh Stephenson ◽  
Simon P. Ringer ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Solute Concentration ◽  
Concentration Profiles ◽  
Field Evaporation ◽  
New Approach ◽  
Depth Direction ◽  
Spread Function

AbstractAtom probe tomography (APT) provides three-dimensional analytical imaging of materials with near-atomic resolution using pulsed field evaporation. The processes of field evaporation can cause atoms to be placed at positions in the APT reconstruction that can deviate slightly from their original site in the material. Here, we describe and model one such process—that of preferential retention of solute atoms in multicomponent systems. Based on relative field evaporation probabilities, we calculate the point spread function for the solute atom distribution in the “z,” or in-depth direction, and use this to extract more accurate solute concentration profiles.

New Frontiers in Electrocatalyst Characterization – Three Dimensional Atomic-Scale Insights By Atom Probe Tomography

2020 ◽  
Vol MA2020-01 (45) ◽  
pp. 2561-2561
Author(s):  
Kevin Schweinar ◽  
Se-Ho Kim ◽  
Joohyun Lim ◽  
Christina Scheu ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale

scholarly journals Three-dimensional atomic mapping of ligands on palladium nanoparticles by atom probe tomography

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kyuseon Jang ◽  
Se-Ho Kim ◽  
Hosun Jun ◽  
Chanwon Jung ◽  
Jiwon Yu ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Pd Nanoparticles ◽  
Atom Probe ◽  
Atomic Scale ◽  
Colloidal Synthesis ◽  
Spectroscopic Techniques

AbstractCapping ligands are crucial to synthesizing colloidal nanoparticles with functional properties. However, the synergistic effect between different ligands and their distribution on crystallographic surfaces of nanoparticles during colloidal synthesis is still unclear despite powerful spectroscopic techniques, due to a lack of direct imaging techniques. In this study, atom probe tomography is adopted to investigate the three-dimensional atomic-scale distribution of two of the most common types of these ligands, cetrimonium (C19H42N) and halide (Br and Cl) ions, on Pd nanoparticles. The results, validated using density functional theory, demonstrate that the Br anions adsorbed on the nanoparticle surfaces promote the adsorption of the cetrimonium cations through electrostatic interactions, stabilizing the Pd {111} facets. In contrast, the Cl anions are not strongly adsorbed onto the Pd surfaces. The high density of adsorbed cetrimonium cations for Br anion additions results in the formation of multiple-twinned nanoparticles with superior oxidation resistance.

Chemical and Structural Characterization of γ/γ′ Interfaces

2012 ◽  
Vol 463-464 ◽  
pp. 20-24
Author(s):  
Kai Zhao
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Scanning Transmission Electron Microscope ◽  
Atomic Scale ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Nickel Base

More attention has been paid to the interfaces since mechanical properties of nickel-base superalloys are determined to some degree by them. The compositional transition across γ/γ′ interfaces and atomic structure of the interfaces was investigated using three-dimensional atom probe tomography and scanning transmission electron microscope equipped with high-resolution Energy Dispersive X-ray Spectrometry. Results show that no obvious segregation to the interfaces or ledges of the precipitates in the present experimental alloys has been observed. Also, adsorption of a solute to the interface was not observed. The interfaces are not flat as usually thought at an atomic scale. The interfacial thickness is about two atomic layers, i.e. 0.7 nm.

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