Publications
439 results found
Gasnier V, Gault B, Nako H, et al., 2013, Influence of experimental parameters on the composition of precipitates in metallic alloys, ULTRAMICROSCOPY, Vol: 132, Pages: 199-204, ISSN: 0304-3991
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- Citations: 5
Vurpillot F, Gault B, Geiser BP, et al., 2013, Reconstructing atom probe data: A review, ULTRAMICROSCOPY, Vol: 132, Pages: 19-30, ISSN: 0304-3991
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- Citations: 115
Loi ST, Gault B, Ringer SP, et al., 2013, Electrostatic simulations of a local electrode atom probe: The dependence of tomographic reconstruction parameters on specimen and microscope geometry, ULTRAMICROSCOPY, Vol: 132, Pages: 107-113, ISSN: 0304-3991
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- Citations: 45
Breen A, Moody MP, Gault B, et al., 2013, Spatial decomposition of molecular ions within 3D atom probe reconstructions, ULTRAMICROSCOPY, Vol: 132, Pages: 92-99, ISSN: 0304-3991
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- Citations: 4
Yao L, Cairney JM, Gault B, et al., 2013, Correlating spatial, temporal and chemical information in atom probe data: new insights from multiple evaporation in microalloyed steels, PHILOSOPHICAL MAGAZINE LETTERS, Vol: 93, Pages: 299-306, ISSN: 0950-0839
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- Citations: 8
Stephenson LT, Moody MP, Gault B, et al., 2013, Nearest neighbour diagnostic statistics on the accuracy of APT solute cluster characterisation, PHILOSOPHICAL MAGAZINE, Vol: 93, Pages: 975-989, ISSN: 1478-6435
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- Citations: 13
Gault B, Felfer PJ, Ivermark M, et al., 2013, Atom probe microscopy characterization of as quenched Zr-0.8 wt% Fe and Zr-0.15 wt% Cr binary alloys, MATERIALS LETTERS, Vol: 91, Pages: 63-66, ISSN: 0167-577X
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- Citations: 8
Du S, Burgess T, Loi ST, et al., 2013, Full tip imaging in atom probe tomography, ULTRAMICROSCOPY, Vol: 124, Pages: 96-101, ISSN: 0304-3991
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- Citations: 19
Gault B, Moody MP, Cairney JM, et al., 2012, Atom probe crystallography, MATERIALS TODAY, Vol: 15, Pages: 378-386, ISSN: 1369-7021
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- Citations: 126
Gault B, Cui XY, Moody MP, et al., 2012, Atom probe microscopy investigation of Mg site occupancy within delta ' precipitates in an Al-Mg-Li alloy, Scripta Materialia, Vol: 66, Pages: 903-906, ISSN: 1359-6462
The composition and site occupancy of Mg within ordered δ′ precipitates in a model Al–Mg–Li alloy have been characterized by atom probe microscopy and first-principles simulations. The concentration in the precipitates is found to be almost the same as that of the matrix; however, we show evidence that Mg partitions to the sites normally occupied by Li in the L12 structure. Density functional calculations demonstrate that this partitioning is energetically favorable, in agreement with experimental results.
Mueller M, Smith GDW, Gault B, et al., 2012, Phase separation in thick InGaN layers - A quantitative, nanoscale study by pulsed laser atom probe tomography, ACTA MATERIALIA, Vol: 60, Pages: 4277-4285, ISSN: 1359-6454
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- Citations: 30
Araullo-Peters VJ, Gault B, Shrestha SL, et al., 2012, Atom probe crystallography: Atomic-scale 3-D orientation mapping, SCRIPTA MATERIALIA, Vol: 66, Pages: 907-910, ISSN: 1359-6462
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- Citations: 52
Felfer PJ, Gault B, Sha G, et al., 2012, A New Approach to the Determination of Concentration Profiles in Atom Probe Tomography, MICROSCOPY AND MICROANALYSIS, Vol: 18, Pages: 359-364, ISSN: 1431-9276
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- Citations: 36
Mueller M, Smith GDW, Gault B, et al., 2012, Compositional nonuniformities in pulsed laser atom probe tomography analysis of compound semiconductors, JOURNAL OF APPLIED PHYSICS, Vol: 111, ISSN: 0021-8979
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- Citations: 31
Mueller M, Gault B, Field M, et al., 2012, Interfacial chemistry in an InAs/GaSb superlattice studied by pulsed laser atom probe tomography, APPLIED PHYSICS LETTERS, Vol: 100, ISSN: 0003-6951
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- Citations: 21
Gault B, Danoix F, Hoummada K, et al., 2012, Impact of directional walk on atom probe microanalysis, ULTRAMICROSCOPY, Vol: 113, Pages: 182-191, ISSN: 0304-3991
In the atom probe microanalysis of steels, inconsistencies in the measured compositions of solutes (C, N) have often been reported, as well as their appearance as molecular ions. Here we propose that these issues might arise from surface migration of solute atoms over the specimen surface. Surface migration of solutes is evidenced by field-ion microscopy observations, and its consequences on atom probe microanalysis are detailed for a wide range of solute (P, Si, Mn, B, C and N). It is proposed that directional walk driven by field gradients over the specimen surface and thermally activated is the prominent effect.
Gault B, Moody MP, Cairney JM, et al., 2012, Appendices, Springer Series in Materials Science, Pages: 313-385
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- Citations: 2
Gault B, Moody MP, Cairney JM, et al., 2012, Tomographic Reconstruction, Springer Series in Materials Science, Pages: 157-209
Tomographic reconstruction sets atom probe tomography apart from most other atomic-resolution microscopy techniques and in some ways makes it more powerful. APT offers an unprecedented ability to map the positions of individual atoms in three dimensions to reveal the structural arrangement of the atoms inside a material is unprecedented. This chapter begins with an introduction of the main principles of the ion projection. We then present the procedure used to build the tomographic reconstruction of the analysed volume atom-by-atom, including descriptions of its performance along with its intrinsic limitations and some typical artefacts in the reconstructed data. Methods to address these limitations are discussed. Further, an approach for measuring the spatial resolution of the reconstruction is presented, along with discussion of the experimental and analytical factors affecting these values. This chapter closes with a description of lattice rectification, an extension to the conventional reconstruction algorithm providing a lattice-based reconstruction.
Gault B, Moody MP, Cairney JM, et al., 2012, Introduction, Springer Series in Materials Science, Pages: 3-7
Atom probe microscopy (APM) is a term that encompasses the various imaging and microanalysis techniques that derive from field ionisation, field emission and field evaporation. Amongst other things, APM provides three-dimensional (3D) analytical mapping of materials with atomic-scale resolution and so offers unique insights into both the chemical composition and atomic structure of matter. Although APM techniques were once considered a niche area of high-field physics and surface science, their development has resulted in a powerful microscope that is now an established method for materials characterisation at the atomic scale. Today, APM is recognised as a burgeoning, mainstream microscopy technique, evidenced by a dramatic recent increase in the number of academic and industrial laboratories worldwide that now have APM capabilities.
Gault B, Moody MP, Cairney JM, et al., 2012, Specimen Preparation, Springer Series in Materials Science, Pages: 71-110
Because atom probe requires the feature of interest to be positioned near the apex of a sharp needle-shaped tip, specimen preparation is an essential, and often extremely challenging, part of any experiment. Recent developments in instrumentation for atom probe microscopy, such as laser-pulsing and the use of wide-field-of-view detectors, have overcome many of the limitations on the types of materials and microstructures that may be studied. Now, more than ever, it is the difficulty of preparing specimens from materials of unusual geometry and/or from site-specific regions that is the limiting factor, and this is particularly so for non-metals. Related to this is the increasing need for highly reproducible techniques that allow statistically significant numbers of site-specific specimens to be fabricated, enabling better quantification and reliability of the subsequent analyses.
Gault B, Moody MP, Cairney JM, et al., 2012, Atom Probe Microscopy and Materials Science, Springer Series in Materials Science, Pages: 299-311
Materials science is an interdisciplinary field devoted to understanding the fundamental origins of materials’ properties to develop and sustain materials technology and engineering. Atom probe microscopy enables the characterisation of many important microstructural features that occur across various length scales in materials. This microscopy can enable new insights into the scientific and engineering aspects of how materials actually work. APM techniques enable the characterisation of the structure and the chemistry of materials, and this is of great significance because both are vital in formulating relationships between microstructure and properties. This short chapter explains how the different methods described previously can be applied to obtain information relevant to the materials scientist.
Gault B, Moody MP, Cairney JM, et al., 2012, Field Ion Microscopy, Springer Series in Materials Science, Pages: 9-28
Field ion microscopy, often referred to as FIM, provides atomic-resolution imaging of the surface of a specimen. A rare gas, called the imaging-gas, is introduced in the vicinity of a positively charged sharp needle. The electric field at the apex of the specimen is of the order of 1010 V m–1. Gas atoms are ionised very close to the tip surface and subsequently accelerated away by the intense electric field. The image that is formed by the impact of these gas ions onto a phosphor screen maps the distribution of the electric field at the surface, which is intrinsically related to the local topography of the tip [1, 2]. The specimen is maintained at an extremely low temperature (5–80 K) to optimise the spatial resolution, which is high enough to provide direct imaging of individual surface atoms.
Gault B, Moody MP, Cairney JM, et al., 2012, Analysis Techniques for Atom Probe Tomography, Springer Series in Materials Science, Pages: 213-297
One of the uniquely powerful aspects of atom probe tomography is the capacity for combining striking three-dimensional (3D) visualisations of atomic-scale microstructure with rigorous quantitative data analysis. Data-mining algorithms can be applied to identify regions of interest, ranging from isolating a single atom to highlighting discrete phases. In modern instruments, tens of millions and often hundreds of millions of ions are routinely acquired, elementally identified and assigned 3D spatial coordinates. Hence, an APT dataset represents a large quantity of atomic-scale structural and chemical information. There are obvious limitations to how much can be learned from mere visual inspection of the tomograms. Therefore, research into the development and application of rigorous data-mining approaches has grown in recent years and is an important frontier for the technique. A challenge is for the analysis techniques to keep pace with the instrumental developments that are generating vastly larger datasets. These larger datasets themselves open up new computational approaches for data-mining.
Gault B, Moody MP, Cairney JM, et al., 2012, Experimental Protocols in Field Ion Microscopy, Springer Series in Materials Science, Pages: 111-120
This chapter focuses on the operation of field ion microscopy (FIM) experiments. The image formed on the phosphor screen or position sensitive detector (eFIM) reveals details of the surface topography. Despite seemingly being static, each spot within a field ion micrograph, such as those presented in Fig. 5.1, constitutes a steady flow of gas ions, roughly 104 per second. There are a variety of experimental parameters that influence the quality of the final micrograph. This most notably includes the type of imaging-gas, the gas pressure, and the specimen temperature. Optimisation of the imaging conditions, by carefully selecting these parameters, should ensure that high-quality FIM images are obtained from which reliable information can be extracted. In this chapter, a step-by-step modus operandi is detailed, followed by a discussion on the influence on the experimental parameters on field ion imaging.
Gault B, Moody MP, Cairney JM, et al., 2012, Experimental Protocols in Atom Probe Tomography, Springer Series in Materials Science, Pages: 121-155
In this chapter, each step of an atom probe tomography experiment is described sequentially, from the alignment of the specimen to its probable fracture, which is the most usual termination of an experiment. The influence of the main experimental parameters—base temperature, detection rate, pulsing mode, etc.—is discussed with the aim of helping the atom probe user to understand the mechanisms underpinning how these parameters could change the data collected, and hence to select parameters to obtain the best possible data. A set of metrics is introduced that can be used to assess the quality of the data. Of these, several can be assessed as the analysis is being performed, including the measured composition within a dataset, the signal-to-background ratio, the quality of the field desorption map, or the amount of multiple events. Of course, the quality of the tomographic reconstruction is an a posteriori criterion.
Gault B, Moody MP, Cairney JM, et al., 2012, From Field Desorption Microscopy to Atom Probe Tomography, Springer Series in Materials Science, Pages: 29-68
As mentioned in Chap. 1, atom probe tomography (APT) exploits the principle of field evaporation to successively remove those atoms at the apex of a needle-shaped specimen. Field evaporation involves the ionisation of these surface atoms, whereupon they are subjected to an electric field force that causes them to accelerate towards a detector under a particular projection. The evaporation event follows immediately after the ionisation of the surface atoms, and this ionisation is induced by the combined effects of a standing (DC) electrostatic field and either high-voltage or laser pulses transmitted to the surface atoms of the specimen. The first technique that exploited this process was field desorption microscopy (FDM), which subsequently evolved into the modern atom probe. A general summary of field evaporation theory is first presented, before a more detailed description of FDM and APT and the specific pulsing techniques.
Xie KY, Breen AJ, Yao L, et al., 2012, Overcoming challenges in the study of nitrided microalloyed steels using atom probe, ULTRAMICROSCOPY, Vol: 112, Pages: 32-38, ISSN: 0304-3991
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- Citations: 14
Gault B, Moody MP, Cairney JM, et al., 2012, Atom Probe Microscopy, Publisher: Springer New York, ISBN: 9781461434351
Burgess T, Du S, Gault B, et al., 2012, Quantification of the zinc dopant concentration in GaAs nanowires, Conference on Optoelectronic and Microelectronic Materials and Devices (COMMAD), Publisher: IEEE, Pages: 41-+, ISSN: 1097-2137
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- Citations: 1
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