In this report, we examine the structure of bimetallic nanomaterials prepared by an electrochemical approach known as hydride-terminated (HT) electrodeposition. It has been shown previously that this method can lead to deposition of a single Pt monolayer on bulk-phase Au surfaces. Specifically, under appropriate electrochemical conditions and using a solution containing PtCl42-, a monolayer of Pt atoms electrodeposits onto bulk-phase Au immediately followed by a monolayer of H atoms. The H atom capping layer prevents deposition of Pt multilayers. We applied this method to ∼1.6 nm Au nanoparticles (AuNPs) immobilized on an inert electrode surface. In contrast to the well-defined, segregated Au/Pt structure of the bulk-phase surface, we observe that HT electrodeposition leads to the formation of AuPt quasi-random alloy NPs rather than the core@shell structure anticipated from earlier reports relating to deposition onto bulk phases. The results provide a good example of how the phase behavior of macro materials does not always translate to the nano world. A key component of this study was the structure determination of the AuPt NPs, which required a combination of electrochemical methods, electron microscopy, X-ray absorption spectroscopy, and theory (DFT and MD).

High tension flexibility in scanning transmission electron microscopy (STEM) enables versatility in the investigation of a broad variety of materials, which formally did not deliver the right contrast or were too beam sensitive at high acceleration voltages.By the introduction of spherical aberration (Cs) correction low voltage STEM has become the major imaging and spectroscopy technique for atomic resolution observation [1,2].When reducing the acceleration voltage and correcting the Cs of the objective lens, the chromatic aberration (Cc) of the electron source becomes resolution limiting and needs to be addressed.This can be achieved by full correction or minimizing its effect on the image resolution [3].The use of the monochromator to minimize the effect of Cc is beneficial in STEM application due to the fact that it improves the performance of EELS applications.To obtain reproducible results during daily operation the handling of a monochromized Cs corrected tool at low voltage needs simplification.In this contribution a Wien filter monochromator [4] and a probe Cs corrector [5] combination on a cubed Titan Themis is used to maintain the atomic resolution in low voltage STEM applications.State of the art low voltage images require both the monochromator and the Cs-corrector to be tuned optimally at the same time in an easy and reproducible way.Therefore we developed fast automatic routines to tune the monochromator and the Cs corrector to give easy access to high performance in LV S/TEM.These routines are quick and deliver within minutes a completely tuned tool.We demonstrate with videos the performance of the tuning and level of automation.The automatic tuning of the monochromator requires no sample and uses the flucam of the Titan cubed as a feedback detector.For optimum Cs correction mainly the lower order aberrations vary in operation and need daily retuning.For this reason a correction routine using a series of HRSTEM images is developed to correct the lower order aberration of the Cs-corrector (focus, 2-fold astigmatism, 3-fold astigmatism, coma) This routine can run on a crystalline sample, even on the area of interest in the zone axis of the crystal to ensure best result and fastest time-to-data.An example of the automatic routine is demonstrated in figure 1, where the images of silicon [110] and GaN [211] before and after autotuning of focus and 2-fold astigmatism on the crystalline material are shown.The negative effect of a large energy spread of the non-monochromized source is illustrated in figure 2 by looking at calculations of the transfer function in STEM with different energy resolution The calculated results are compared to images taken with different energy resolution, high tensions and beam currents, set-up via the above described automatic routines.The combination of XFEG gun with monochromator delivers even at low voltages high probe currents for analytical work.We discuss the influence of the energy resolution on the image quality.Therefore HR-STEM analytical and imaging results of various materials are presented to prove the robustness of the alignment procedures and the performance of the Wien filter/Cs corrector combination at low voltages down to 30kV.(Figure 3)

Journal Article Reducing the Missing Wedge in TEM Tomography Get access A Genc, A Genc FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR, USA Search for other works by this author on: Oxford Academic Google Scholar L Kovarik, L Kovarik Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, USA Search for other works by this author on: Oxford Academic Google Scholar L Pullan, L Pullan FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR, USA Search for other works by this author on: Oxford Academic Google Scholar J Ringnalda J Ringnalda FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 22, Issue S3, 1 July 2016, Pages 26–27, https://doi.org/10.1017/S1431927616000982 Published: 25 July 2016

Since aberration correction has been applied on modern electron microscope systems, there has been a need to demonstrate the benefits of this capability and in some respect, to justify the cost of these complex systems. Sometimes the justification of such a system is by the presentation of a colorful elemental map which correlates with the atomic periodicity in the sample. This type of visualization, while artistic, may not be sufficient to characterize materials at the levels proclaimed, since there are many events happening which are difficult to place with atomic certainty. There are many benefits of the correctors on the imaging side of the sample by removing delocalization and improving the image interpretability for phase contrast imaging, however there is a strict requirement on the sample both in terms of cleanliness, thickness and damage layers. In the case of correctors on the condenser or probe forming part of the microscope, this requirement is only amplified especially when the imaging techniques are combined with various spectroscopies.

Scanning Transmission Electron Microscopy (STEM) has been enhanced in terms of resolution and probe current with the implementation of aberration correctors on the probe forming lens of a transmission electron microscope (TEM).Using the presently available techniques of measuring resolution in STEM mode, the resolution of the image, perceived to indicate the size of the electron beam (probe) is determined by measuring the extension of spatial frequencies present in the fast Fourier transform (FFT) of a STEM image.The probe aberration corrector allows a larger convergence angle to be used, thus increasing the current that can be put into a focused probe.However this probe is only really in focus in a very small crossover within the TEM sample of finite thickness (t).Realistically samples of thickness of the order of 5-15 nm benefit of probe correction because of the limited depth of field (DOF) of the aberration corrected probe at large convergence angles.Samples that are thicker either maintain the smaller probe entering into the surface through channeling, or often suffer divergence of the beam and therefore a worsening of the analytical performance as the probe travels through the sample [1,2].For crystalline samples, because the incoming probe has more angular spread with the probe corrector, coherent diffraction effects result in more spots in the FFT leading to the perception of increased resolution, however from an analytical point of view, the probe interactions after the initial surface reaction do not enhance the spatial resolution, and this limitation has to be considered for probe corrected systems.distance (d f ) of the probe within the TEM sample, where we expect larger d f and smaller variation in probe intensity by using smaller a.As seen in Figure 1b, there is a wide distribution of Cr deficient `particles of the Ni based superalloy shown in the Cr K elemental maps taken at varying of 21 (left map) and 10 (right map) mrad, respectively.When these images are analyzed in more detail, it becomes clear that `particles that are sized below ~5-10 nm disappear in the XEDS elemental maps taken using

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Journal Article Live Imaging of Reversible Domain Evolution in BaTiO3 on the Nanometer Scale Using in-situ STEM and TEM Get access Alina Schilling, Alina Schilling Department of Physics and Astronomy, School of Mathematics and Physics, Queen's University Belfast, UK, BT7 1NN Search for other works by this author on: Oxford Academic Google Scholar Bastian Barton, Bastian Barton FEI Company, Europe NanoPort, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Joerg R Jinschek, Joerg R Jinschek FEI Company, Europe NanoPort, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Luigi Mele, Luigi Mele FEI Company, Europe NanoPort, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Pleun Dona, Pleun Dona FEI Company, Europe NanoPort, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Jan Ringnalda, Jan Ringnalda FEI Company, Europe NanoPort, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Miryam Arredondo, Miryam Arredondo Department of Physics and Astronomy, School of Mathematics and Physics, Queen's University Belfast, UK, BT7 1NN Search for other works by this author on: Oxford Academic Google Scholar Joshua F Einsle, Joshua F Einsle Department of Physics and Astronomy, School of Mathematics and Physics, Queen's University Belfast, UK, BT7 1NN Search for other works by this author on: Oxford Academic Google Scholar Marty Gregg Marty Gregg Department of Physics and Astronomy, School of Mathematics and Physics, Queen's University Belfast, UK, BT7 1NN Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 20, Issue S3, 1 August 2014, Pages 1560–1561, https://doi.org/10.1017/S1431927614009532 Published: 27 August 2014

Journal Article Towards Quantitative EDX Results in 3 Dimensions Get access Bart Goris, Bart Goris EMAT, University of Antwerp, Antwerp, Belgium Search for other works by this author on: Oxford Academic Google Scholar Bert Freitag, Bert Freitag FEI Company, P.O. Box 80066, KA 5600 Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Daniele Zanaga, Daniele Zanaga EMAT, University of Antwerp, Antwerp, Belgium Search for other works by this author on: Oxford Academic Google Scholar Eva Bladt, Eva Bladt EMAT, University of Antwerp, Antwerp, Belgium Search for other works by this author on: Oxford Academic Google Scholar Thomas Altantzis, Thomas Altantzis EMAT, University of Antwerp, Antwerp, Belgium Search for other works by this author on: Oxford Academic Google Scholar Jan Ringnalda, Jan Ringnalda FEI Company, P.O. Box 80066, KA 5600 Eindhoven, The Netherlands Search for other works by this author on: Oxford Academic Google Scholar Sara Bals Sara Bals EMAT, University of Antwerp, Antwerp, Belgium Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 20, Issue S3, 1 August 2014, Pages 766–767, https://doi.org/10.1017/S1431927614005558 Published: 27 August 2014

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

We report on a novel biocompatible hierarchical TiO 2 porous coating on the surface of Ti, processed via anodic oxidation. The coating consists of large (~1–20 mm) pores on the microscale and nanotubes (~50 nm diameter) on the nanoscale. This structure is exciting because of its potential application as a bioactive coating for Ti bone implants. Surface characterization of the coating showed nanotubes of relatively uniform diameter. The interface between TiO 2 nanotubes and Ti, studied by transmission electron microscopy, was incoherent. The tubes were also somewhat interconnected.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Studies of the transformation kinetics and resulting microstructures of C materials processed at various temperatures are presented. C4 materials are produced through a displacement reaction between solid silica and molten aluminum. Evidence suggests that three distinct, temperature related processing regimes exist, each of which yields characteristic kinetic behavior and microstructures. Through the identification of the various phases and morphologies present in the microstructure, coupled with the observed kinetic behavior, a transformation mechanism for the evolution of the material is proposed.

We resolve the plasmon modes from individual silver nanowires and gold nanorods by means of high-resolution electron energy loss spectroscopy. We compare our experimental results to the analytical description of the energy loss probability for electrons incident on a prolate spheroid.

The excitation of surface plasmons in individual silver nanowires and gold nanorods is investigated by means of high-resolution electron energy loss spectroscopy in a transmission electron microscope. The transverse and longitudinal modes of these nanostructures are resolved, and the size variation of the plasmon peaks is studied. The effect of electromagnetic coupling between closely spaced nanoparticles is also observed. Finally, the relation between energy-loss measurements and optical spectroscopy of nanoparticle plasmon modes is discussed.

Extract Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Extract Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Extract Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007