bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compact back-scattered electrons' energy analyzer for standard SEM
Authors: Likharev S. , Kramarenko A. , Vybornov V. 
Published: June 2020

At present time the interest is growing considerably for theoretical and experimental analysis of back-scattered electrons (BSE) energy spectra. It was discovered that a special angle and energy nitration of BSE flow could be used for increasing a spatial resolution of BSE mode, sample topography investigations and for layer-by layer visualizing of a depth structure. In the last case it was shown theoretically that in order to obtain suitable depth resolution it is necessary to select a part of BSE flow with the directions of velocities close to inverse to the primary beam and energies within a small window in the high-energy part of the whole spectrum.A wide range of such devices has been developed earlier, but all of them have considerable demerit: they can hardly be used with a standard SEM due to the necessity of sufficient SEM modifications like installation of large accessories in or out SEM chamber, mounting of specialized detector systems, input wires for high voltage supply, screening a primary beam from additional electromagnetic field, etc. In this report we present a new scheme of a compact BSE energy analyzer that is free of imperfections mentioned above.
A new approach to the study of solid-state reactions in oxide ceramics
Authors: Kotula Paul G. 
Published: June 2020

Thin-film reactions have potential applications for the production of buffer layers in heterojunctions and for the reaction bonding of materials. The main drawback to these applications at present isthat the effect of interface morphology on the initial kinetics of solid-state reactions is not well understood. In order to study the kinetics and mechanisms of thin-film reactions in oxide ceramics, a new method has been developed. The approach relies on the production of a well characterized high-quality oxide thin film on a single-crystal oxide substrate which makes up the idealized reaction couple-a ‘single-crystal’ thin film in intimate contact with a single crystal substrate. The thin-film approach localizes the reaction near the surface of the specimen so that conventional cross-sectioning techniques can be utilized. Additionally, the scale of the reaction is of the order of tens of nanometers or less which is ideally suited to high-resolution SEM or conventional TEM.NiO/α-Al2O3is a model system for the study of solid-state reactions.
Applications of electron holography to ferromagnetic and superconductive materials
Authors: Tonomura Akira. 
Published: June 2020

Electromagnetic fields are not observable with conventional electron microscopy: The fields deflect an incident electron beam but no contrast is produced in the electron micrograph for the fields since all the electrons deflected at an object point are focused into a single image point through the electron lens. The information about the electomagnetic fields is included in the deflection distribution or the phase distribution of an electron beam, which is lost in electron micrographs. Electron interferometry has been carried out since 1950s using a transmission electron microscope equipped with an electron biprism to make ultra-fine measurements. The advent of a "coherent" field-emission electron beam has greatly expanded the range of applications and possibilities: Electric and magnetic fields are directly observed as equipotential lines and magnetic lines of force in an electron-holographic interference micrograph. Precision in phase measurement has increased to 2π/50 thanks to a phase amplification technique peculiar to holography.In magnetic field observation, contour fringes in an interference micrograph directly indicate projected magnetic lines of force in h/e flux units. An example of a magnetic field micrograph is shown in Fig. 1.
Automatic idexing of electron-backscatter diffraction patterns
Authors: Wright S. I. 
Published: June 2020

A typical Backscatter Kikuchi Diffraction pattern (BKD, also referred to in the literature as an EBSP or a BEKP) is shown in figure 1. Since the bands in the pattern represent planes in the diffracting volume, the lattice orientation can be determined from their geometrical arrangement. The task of correctly orienting a BKD can be broken into two parts: 1) finding the salient features in the pattern (either the diffraction bands or the intersections of the bands) and 2) using these features to determine the lattice orientation. Recent advances in feature detection in BKDs along with methods for digital image enhancement will be described in some detail. The determination of orientation from a set of detected bands (or intersections of bands) will also be discussed.Dingley has demonstrated that lattice orientation can be practically obtained from BKDs by imaging the diffraction patterns using a low light level video camera and indexing the patterns with the aid of an online computer.
Slip traces caused by plastic deformation during recrystallization of thin metal sheets
Authors: Lin H. , Pope D. P. 
Published: June 2020

During a study of mechanical properties of recrystallized B-free Ni3Al single crystals, regularly spaced parallel traces within individual grains were discovered on the surfaces of thin recrystallized sheets, see Fig. 1. They appeared to be slip traces, but since we could not find similar observations in the literature, a series of experiments was performed to identify them. We will refer to them “traces”, because they contain some, if not all, of the properties of slip traces. A variety of techniques, including the Electron Backscattering Pattern (EBSP) method, was used to ascertain the composition, geometry, and crystallography of these traces. The effect of sample thickness on their formation was also investigated.In summary, these traces on the surface of recrystallized Ni3Al have the following properties:1.The chemistry and crystallographic orientation of the traces are the same as the bulk. No oxides or other second phases were observed.2.The traces are not grooves caused by thermal etching at previous locations of grain boundaries.3.The traces form after recrystallization (because the starting Ni3Al is a single crystal).4.For thicknesses between 50 μm and 720 μm, the density of the traces increases as the sample thickness decreases. Only one set of “protrusion-like” traces is visible in a given grain on the thicker samples, but multiple sets of “cliff-like” traces are visible on the thinner ones (See Fig. 1 and Fig. 2).5.They are linear and parallel to the traces of {111} planes on the surface, see Fig. 3.6.Some of the traces terminate within the interior of the grains, and the rest of them either terminate at or are continuous across grain boundaries. The portion of latter increases with decreasing thickness.7.The grain size decreases with decreasing thickness, the decrease is more pronounced when the grain size is comparable with the thickness, Fig. 4.8.Traces also formed during the recrystallization of cold-rolled polycrystalline Cu thin sheets, Fig. 5.
Effect of alloy grain size on oxidation resistance of silica-coated stainless steel
Authors: McDowell C. S. , Basu S. N. 
Published: June 2020

Oxidation resistance of stainless steels, which rely on the formation of a Cr2O3 (chromia) scale, can be further improved through minor alloying additions such as Al or Si, or by application of coatings to the exposed surfaces. Although, additions of Si to austenitic steels have demonstrated an improvement in oxidation resistance, high Si contents can be detrimental to the mechanical properties of these alloys. The application of a silica coating on the surface of the stainless steel provides improved oxidation resistance without detrimental effects on the mechanical properties. This study examines the effect of the grain size of the stainless steel on the effectiveness of a silica coating as an oxidation barrier.Fully austenitic stainless steel of composition Fe-18(wt%)Cr-20Ni-1.5Mn was produced in both coarsegrained and fine-grained form. The coarse-grained alloy, with a grain size of approximately 100 μm, was produced by casting and hot rolling. The fine-grained alloy, with a grain size of approximately 5 μm, was produced by rapid solidification powder processing, followed by consolidated by hot isostatic pressing and swaging.
Nano-probe x-ray analysis and high-resolution imaging on planar defects in high-pressure synthesized infinite-layer superconductor
Authors: Wang Y. Y. , Zhang H. , Dravid V. P. , Zhang H. , Marks L. D. , Han P. , Payne D. A. 
Published: June 2020

Azuma et al. observed planar defects in a high pressure synthesized infinitelayer compound (i.e. ACuO2 (A=cation)), which exhibits superconductivity at ~110 K. It was proposed that the defects are cation deficient and that the superconductivity in this material is related to the planar defects. In this report, we present quantitative analysis of the planar defects utilizing nanometer probe xray microanalysis, high resolution electron microscopy, and image simulation to determine the chemical composition and atomic structure of the planar defects. We propose an atomic structure model for the planar defects.Infinite-layer samples with the nominal chemical formula, (Sr1-xCax)yCuO2 (x=0.3; y=0.9,1.0,1.1), were prepared using solid state synthesized low pressure forms of (Sr1-xCax)CuO2 with additions of CuO or (Sr1-xCax)2CuO3, followed by a high pressure treatment.Quantitative x-ray microanalysis, with a 1 nm probe, was performed using a cold field emission gun TEM (Hitachi HF-2000) equipped with an Oxford Pentafet thin-window x-ray detector. The probe was positioned on the planar defects, which has a 0.74 nm width, and x-ray emission spectra from the defects were compared with those obtained from vicinity regions.
Surface morphology change induced by bulk order-disorder transition in Cu3Au alloy
Authors: Huang Y. , Gajdardziska-Josifovska M. , Cowley J. M. 
Published: June 2020

In recent years the surfaces of Cu3Au, a typical ordering alloy, have attracted interest from many aulhors[l-6], because the surface is a good example for testing general theories of the 2-D order-disorder phase transition, and also because it is a good material for studying the behavior of bimetallic alloy surfaces and their reactions with surface impurities. Previous work on Cu3Au surface mostly used macroscopic techniques and provided only information averaged over a largearea. In this work the microscopic imaging and diffraction methods are used to study the (111) surface on a more localized scale. Reflection Electron Microscopy (REM) was used to directly image the surface, and the selected-area RHEED was used to determine the local surface crystal structure and orientation.The samples used for observation are single crystal spheres prepared by melting a small piece of Cu3Au suspended on a thin Mo wire. The actual compositions of the samples are about Cu0.7Au0.3. The (111) facets on these spheres were then cleaned by the conventional ion-milling-heating method in a UHV environment.
Reflection electron microscopy (REM) of NaCl crystals
Authors: Hsu Tung 
Published: June 2020

NaCl and other alkaline halide crystals are unstable under the electron beam and therefore have seldom been examined with the various electron beam techniques. Surfaces of these crystals, however, are of fundamental and application interests. There has been a considerable effort in studying these surfaces using the replica methods.Reflection high energy electron diffraction (RHEED) and reflection electron microscopy (REM) have been successfully applied to the study of stable insulators. Since direct observation on an uncoated surface is always desirable, we tried RHEED and REM on cleaved NaCl(100) surfaces.The experiment was carried out on a JEOL JEM-200CX electron microscope with a high tilt side-entrystage. The accelerating voltage of lOOkV was used throughout the experiment. There is no special protection to the specimen except the standard anti-contamination cold finger. The initial effort of doing ordinary REM on NaCl was a failure: When the electron beam and the specimen were properly tilted toget a good RHEED pattern, the bright pattern remained for only a couple of seconds and then turned into a pattern of weak spots and high diffuse background. The bright REM image also lost its contrast in a few seconds.
Auger and TEM analysis of multilayer IC contacts
Authors: Buttry R. W. , Hills C. R. , Nelson G. C. , Tribble T. 
Published: June 2020

With the continued shrinkage of the dimensions (both laterally and in depth) of integrated circuits (IC), knowledge of the interactions that occur over nanometer scale distances becomes increasingly important. This requirement has pushed the capabilities of the tools used to analyze these structuresto their maximum. Two techniques which are frequently used to analyze thin layer structures are AugerElectron Spectroscopy (AES) and Transmission Electron Microscopy (TEM).AES combined with ion beam sputtering is used to measure the elemental composition as a function of sputter time. With suitable calibration, the sputter time scale can be converted to a depth scale. Theprofiles can also be used to study the interfacial reactions for thin layers. TEM is frequently used to accurately measure layer thicknesses and the layer elemental constituents can be identified byEnergy Dispersive Spectroscopy (EDS). When the layer thicknesses approach a few tens of A there are problems associated with interpreting the data from both of these techniques, particularly the data obtained near the interfaces.
Structural and chemical analysis of Pd-Ge ohmic contacts to epitaxially lifted-off GaAs
Authors: Rajesh R. , Liu J. , Fathollahnejad H. , Carpenter R. W. , Maracas G. N. 
Published: June 2020

For the past decade, there has been considerable focus on low resistance Pd-Ge ohmic contacts to GaAs. One approach toward achieving thermodynamically stable ohmic contacts is to consider solid-phasereactions for contacts, rather than the liquid phase interactions that occur upon ohmic alloying of Au-Ge-based systems. The two classifications to this approach are: low temperature annealing (<500°C), mainly using Pd, and high temperature annealing (<500°C), mainly using In. The low temperature annealing class is more compatible with existing GaAs technology, hence the attention to Pd-based systems, particularly Pd-Ge. There has also been tremendous interest in hybrid GaAs-on-Si technology. As an alternative to direct lattice-mismatched growth of GaAs on Si, the epitaxial lift-off (ELO) technique has been used, wherein GaAs devices grown on GaAs substrates can be removed and bonded to any substrate regardless of orientation and/or lattice matching criteria. This process yields high quality dislocation-free GaAs-based devices for hybrid applications.In this study, we demonstrate a low resistance non-alloyed Pd-Ge ohmic contact to epitaxialiy lifted-off n-type GaAs.
Quantitative footprints, in size & number density, of a TEM search for defects in VLSI silicon
Authors: Siriwardane H. , Fraundorf P. 
Published: June 2020

Electron (and scanning tip) microscopes permit the study of objects over a wide dynamic range of size and number density. When reporting results, null or otherwise, of a microscope search to colleagues wishing to fill in blanks in their image of what is and is not there, a few words or numbers oftendoes not convey what really can and cannot be inferred by the technique. We show here some plots which provide a quantitative picture of what was and was not seen, in the context of what might and mightnot be further investigated. Moreover, we illustrate how the format can provide contextual information on the material system under study, using oxygen precipitates in single crystal Czochralski silicon as the example.A microscope observing session usually involves examination (or recording) of Ni fieldsof view of width Wi on a specimen, where the index i runs over the number of different magnifications (or field widths) used by the microscopist. Each field of view might allow one to discernobjects whose largestdimension is no more than DiμWi, where μ is a constant typically between 0.01 and 0.001, dependingon the nature of the contrast mechanisms and the geometry of the objects of interest. The region of size & number density space thus investigated byNi fields of view can be marked on a plot of maximum dimension versus number per unit area(see Fig. 1) as the region both to the right of a vertical lineat l/(NiWi),and above a horizontal line at maximum dimension μWi. The region investigated by a larger number of fields of view at that magnification simply extends the examined region further to the left.
Visualizing emulsion polymer particles with an Scanning Electron Microscope equipped with transmission detector
Authors: Charaf U. K. 
Published: June 2020

It is difficult to obtain good images of small emulsion polymer particles with an older model SEM which necessitates sputter coating and high accelerating voltage. For the purpose of screening a large number of samples before selecting some for TEM imaging off site, a transmission detector was fitted below the sample holder of an Amray 1600 (Turbo) SEM.Emulsion polymers with particle sizes from 10 to 100 μm were diluted in 1 % phosphotungstic acid (or other negative stain) and applied to Formvar and carbon coated grids. Lacking sophisticated freeze drying equipment, the grids with the sample films were cooled by immersing the stem of the grid holder in liquid nitrogen. They were then freeze dried in vacuo in an old sputter coaterInspite of some inherent difficulties, (such as high beam sensitivity), reasonably good resolution was obtained at 30 KV to magnifications of 150,000x.. Image processing was used, where applicable, to sharpen the images.
Visualization of compositional data in microscopy: Representation schemes and software tools
Authors: Bright David S. 
Published: June 2020

Consider quantitated x-ray maps as micrographs which are displayed as gray level images where the gray level of each pixel represents useful quantitative information. Although the gray levels correspond to elemental concentrations, well known illusions or response characteristics of the human visualsystem interfere with matching the gray levels of the image to the accompanying numerically annotatedgray scale. The effect of different backgrounds or surrounds is illustrated in Fig. 1. More subtle effects due to an abrupt transition in gray level is shown in Fig. 2. In Fig. 2, the squares appear differently if the brightness ‘edge’ in the center is covered with a pencil: for example, the lower squares appear to be uniform and equally bright.Similar effects also occur for color images. Visual perception effects aside, interpreting colors quantitatively by matching is more difficult than for black and white images, as will be shown in the talk. Color imaging methods can display only three elements at a time, whereas the phases of interest might depend on the interrelationships of four or more elements. Intensity profiles, such as in Fig. 2, do display values unambiguously, but they represent only a small fraction of the data. An appropriately labeled scatter diagram or two dimensional histogram can represent all of the data.
Stopping-power determination for compound by EELS
Authors: Joy David C. , Luo Suichu , Dunlap John R. , Williams Dick , Cao Siqi 
Published: June 2020

In Physics, Chemistry, Materials Science, Biology and Medicine, it is very important to have accurate information about the stopping power of various media for electrons, that is the average energy loss per unit pathlength due to inelastic Coulomb collisions with atomic electrons of the specimen along their trajectories. Techniques such as photoemission spectroscopy, Auger electron spectroscopy, and electron energy loss spectroscopy have been used in the measurements of electron-solid interaction. In this paper we present a comprehensive technique which combines experimental and theoretical work to determine the electron stopping power for various materials by electron energy loss spectroscopy (EELS ). As an example, we measured stopping power for Si, C, and their compound SiC. The method, results and discussion are described briefly as below.The stopping power calculation is based on the modified Bethe formula at low energy:where Neffand Ieffare the effective values of the mean ionization potential, and the number of electrons participating in the process respectively. Neffand Ieffcan be obtained from the sum rule relations as we discussed before3 using the energy loss function Im(−1/ε).
Grain-boundary compositional measurements in complex high-temperature Ni-base alloys using x-ray spectroscopy
Authors: Hall E. L. , Blankenship C. P. , Henry M. F. 
Published: June 2020

Thermal treatment of advanced Ni-base alloys used in critical aircraft engine components can have a significant effect on both the microstructure and properties of these alloys. One important property that can be strongly affected by heat treatment is the time-dependent fatigue crack propagation rate along grain boundaries. It is possible for heat treatments to affect the morphology, chemistry, andphase distribution along the grain boundaries in these complex multiphase alloys. Structure-property correlations require the measurement of each of these parameters. By far, the least tractable of these is the measurement of grain boundary chemistry.X-ray spectroscopy in the AEM has been shown to be a very powerful method for measuring grain boundary chemistry in single-phase Fe and Ni-base alloys, among others. In the case of a singlephase Ni-base alloy such as IN600, heat treatments in the range of 500-750&C cause precipitation of Crrich carbides at grain boundaries and the depletion of Cr from the grain-boundary segments between precipitates via a collector-plate mechanism. Measurement of Cr-depletion at the grain boundaries and Cr-depletion profiles across boundaries is straightforward.
Nanoscale encapsulation of Fe crystallites within a protective graphite cage
Authors: Yao N. , Navrotsky A. , Leinenweber K. 
Published: June 2020

Since the discovery of carbon fullerene nanotubules by Iijima using high resolution transmission electron microscopy, there has been a great deal of interest in the properties of tubules and related structures. Recently, it was reported that in the presence of transition-metal catalyst particles, abundant single-shell carbon nanotubes or graphite-encapsulated metal nanocrystals can be produced in a carbon-arc synthesis chamber using electrodes containing both carbon graphite and metal. The vaporization of metal from anode in an inert gas environment takes place simultaneously with the production of soot from the carbon cathode. In this paper, we report that the graphite-encapsulated iron nanocrystals can be made by electron beam irradiation of iron particles on an amorphous carbon support in situ.The initial aim of our experiments was to study the microstructure and defects of a new calcium iron (II) titanate, CaFeTi2O6, compound, which was synthesized at 12-15 GPa and 1200-1400°C. This material contains a few iron particles in addition to the major oxide phase.