bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative Investigations of Interfaces and Grain Boundaries by Phase Contrast Electron Microscopy with Ultra High Resolution
Authors: Kisielowski C , Plitzko JM , Lartigue S , Radetic T , Dahmen U 
Published: July 2020

Abstract
Recent progress in High Resolution Transmission Electron Microscopy makes it possible to investigate crystalline materials by phase contrast microscopy with a resolution close to the 80 pm information limit of a 300 kV field emission microscope'"". A reconstruction of the electron exit wave from a focal series of lattice images converts the recorded information into interpretable resolution. The present contribution illustrates some recent applications of this technique to interfaces.
Fig. 1 shows a reconstructed electron exit wave of a heterophase interface between GaN and sapphire. The experiment takes advantage of three factors: First, we resolved the GaN lattice in projection, which requires at least 0.15 nm resolution. The projection eliminates the stacking fault contrast that usually obscures lattice images in the commonly recorded projection. Thus, image interpretation is drastically simplified. Second, all atom columns at the interface and in the sapphire are resolvable with a smallest projected aluminum - oxygen spacing of 85 pm in the sapphire.
Energy -Loss Fine Structures at the Si-Gd2O3, Interface
Authors: Botton GA , Gupta J A , Landheer D , McCaffrey JP , Sproule GI , Graham MJ 
Published: July 2020

Abstract
In recent years, electron energy loss spectroscopy has provided high spatial resolution information on the elemental composition of interfacial reactions. with the use of field emission guns in conventional TEM or STEM, additional information on the chemical, structural and electronic state at grain boundaries and interfaces can also be obtained (e.g. Ref. 1 and 2). in the study of new types of materials for semiconductor applications such as high-K dielectrics, high spatial resolution information of this type is of critical importance as the dimensions of the structures are reduced and the ultimate electronic properties become size dependent. This paper discusses the analysis of near edge structure information obtained at the Si-Gd2O3 interface, a system with great potential for the next generation of gate material.
The preparation of the thin films and the sample preparation details are given elsewhere3 and only a summary of the characterization method and results are described here.
Electronic Structure Investigations of Metal / SrtiO3 Interfaces Using EELS
Authors: van Benthem Klaus , Scheu Christina , Sigle Wilfried , Elsässer Christian , Rühle Manfred 
Published: July 2020

Abstract
Ni, Pd and Cr thin films were grown on (100)SrTiO3 surfaces by molecular beam epitaxy at substrate temperatures of TNJ, pd=650°C and Tcr =150°C. Electron energy-loss spectroscopy (EELS) and high resolution transmission electron microscopy (HRTEM) were applied to investigate the local electronic structure and the atomic structure of the interfaces, respectively. Analytical microscopy was carried out with a parallel energy-loss spectrometer (PEELS766) attached to a dedicated scanning transmission electron microscope (STEM) operated at 100keV, which has a point resolution of 0.22 nm. HRTEM studies were performed on a Jeol JEM ARM 1250 operated at 1250keV (0.12 nm point resolution). Conventional TEM and HRTEM experiments showed epitaxial orientation relationships between the thin metal films and the substrate for each interface.
The electronic structure of the interfaces in terms of the site- and symmetry projected density of states (PDOS) above the Fermi-level can be extracted from the electron energy-loss near-edge structures (ELNES).
TEM Analysis of an Alumina Bicrystal Section Using a Fib
Authors: Fairer Jeffrey K , Ravishankar N , Michael Joseph R , Barry Carter C 
Published: July 2020

Abstract
Grain boundary migration (GBM) during the sintering and densification of a polycrystalline ceramic material occurs as a result of mass transport across an interface. When there is a liquid film present, either due to additives used for liquid-phase sintering or unavoidable impurities in the material, the mass transport can be visualized in terms of dissolving material from one grain and precipitating it on another. in order to study the effects of crystallography on GBM in the presence of a liquid phase, alumina bicrystals have been fabricated with anorthite (CaA12Si208) glass films at the interface. The alumina-anorthite system in a bicrystal geometry is used because the pseudo-binary phase diagram of the system is well known, the bicrystal geometry allows for control over the original interface misorientation, and the glassy phase of anorthite is the most commonly occurring glass in commercially used alumina.
Fig. 1 is a secondary-electron SEM image of an alumina bicrystal recorded using a field-emission SEM (Hitachi S900) operating at 5 kV.
Nonorthogonal Twining in Epitaxial SrRuO3 Thin Films Grown on (001) LaAlO3
Authors: Tian W , Jiang J C , Pan X Q 
Published: July 2020

Abstract
Nonorthogonal twinings have commonly been observed in perovskite oxides such as SrTi03 and BaTi03. Among them, the ﹛111﹜ Σ3 type twining exists with a relative large amount of population and has been extensively studied. By combining quantitative high resolution transmission electron microscopy (HRTEM) and spatially resolved electron energy loss spectroscopy (EELS), one was able to determine the atomic structure of the ﹛111﹜Σ3 twin boundary in these oxides.[l] On the other hand, nonorthogonal twinings in SrRuO3 have been much less studied. SrRu03, a ternary ruthenium metal oxide, has a perovskite-compatible structure and exhibits low electrical resistivity (10-4 Ω•cm), showing an unparallel technique importance in microelectronic applications. Since the properties of material strongly depend on the microstructure and defect configurations, it is important to study the twining structures and their formation mechanisms in SrRuO3 thin films.
Transmission electron microscopy (TEM) was used to study the SrRuO3 thin films grown on (001) LaAlO3 by 90° off-axis rf sputtering.
Crystal Polarity Determination by Electron Channeling
Authors: Tafto J 
Published: July 2020

Abstract
Multilayers, heterostructures, nanostructures and composites are of great interest to the materials scientists, and frequently we encounter crystals lacking centrosymmetry. Thus crystal polarity determination on a microscopic scale is becoming increasingly important in describing interface structures and the internal defects in small crystals. in many cases the polarity of a crystallite can be determined by convergent beam electron diffraction, CBED. Powerful alternatives are to monitor the electron induced x-ray emission, EDS, or electron energy losses, EELS, under channeling conditions. While the determination of the phase of the structure factors, and thus the determination of the crystal polarity, relies on many beam diffraction effects when the CBED technique is used, two-beam experiments provide information about the phase of the structure factor when localized EDS or EELS signals are detected under channeling conditions.
The experimental conditions used to determine the polarity and absolute orientation from electron channeling are similar to those used in ALCHEMI experiments to locate small amounts of atoms by electron channeling.
Dechanneling Effects in EELS and EDXS Analysis of Ybacu-Oxides
Authors: Miller Peter 
Published: July 2020

Abstract
Quantitative analysis in the TEM by EELS or EDXS depends on the K-factor method in which uniform ionization, independent of specimen orientation and thickness, is assumed. This assumption is of limited validity for crystals, where channeling of the electron wave ψ affects the ionization rate as observed in both energy loss and X-ray signals. Both EELS and EDXS are sensitive to changes in ψψ*near the atomic sites, and this variation as a function of crystal orientation forms the basis for ALCHEMI. Simultaneously recorded EELS and EDXS spectra were used to monitor changes in Cu/Ba ratio from YBaCu-oxides using L2,3/M4,5 ionization edges or K/L X-rays respectively. Although the acceptance aperture for EELS (11 mrad at 300 keV) may not be sufficiently large to mask double-channeling effects, it is small enough that momentum transfer is sufficiently limited to enhance derealization. Thus it is expected that the EELS signal should be less sensitive to crystal orientation than EDXS (an estimate of impact parameters yields 0.73 and 0.61 Å for the Ba and Cu energy loss signals, reducing to 0.06 and 0.04 Å respectively for X-ray emissions).
Atomic Site Occupancy of Platinum Group Metals in the γ’ (Ll2) Phase of a γ-γ’ Complex Nickel Base Superalloy Using Alchemi (Atomic Location by Channnelling Enhanced Microanalysis)
Authors: Ofori A P , Humphreys C J 
Published: July 2020

Abstract
Nickel-base superalloys (NBSAs) have remarkable mechanical properties (and corrosion resistance) at elevated temperatures. Single crystal NBSAs have found major use as turbine blades in aeroengines, where there is a large world market because the turbine blades have to be replaced at regular intervals. in order to develop engines with higher efficiency, considerable efforts are being devoted to enhance the temperature capabilities of superalloys. The two phase γ-γ’ structure that is crucial to NBSA characteristics is primarily produced by the presence of Al in combination with Ni: above a critical concentration the Ll2 γ’ phase based on Ni3Al precipitates out of the γ Ni-base solution. However, superalloys usually contain many other alloying elements such as Cr, Co, Mo, W and Ta to enhance strength and impart higher temperature performance. Among these alloying additions, much attention has recently been paid to Re because of its contribution to the improvement of both creep and corrosion properties.
The Role of Simulation in ALCHEMI
Authors: Rossouw Chris 
Published: July 2020

Abstract
Contrast in zone axis channelling patterns, formed by variations in characteristic X-ray emission rates as an electron beam is scanned in angle, is related to projected sublattice site symmetries of ionized atoms within the unit cell. Whereas overall Brillouin zone geometry is identical to that observed in large angle convergent beam patterns, this incoherent X-ray channelling contrast is related to ADF or BSE contrast by integration over thickness of the signal generated within the specimen. Contrast is thus relatively stable and easily interpretable.1 This is useful in separating the response of dilute atoms from abundant atomic species, since the specific channelling pattern of each atom has its own overall fingerprint. Correlation of patterns formed from Ta-doped TiAl with bright field LACBED is shown in Fig. 1 (clearly Ta occupies Ti sublattice sites). No simulation of channelling contrast is necessary if minority atomic species are distributed over sublattice sites in a way that can be reconstructed from a linear superposition of majority (or host) atom sites that form part of the regular lattice structure. The distribution over sublattice sites may be determined by any one of a variety of analysis methods.2,3
A Routine to Determine the Shift of Kikuchi Bands in EBSD to Sub-pixel Resolution
Authors: Tao Xiaodong , Eades Alwyn 
Published: July 2020

Abstract
The long-term aim of our research is to detect and image dislocations in the SEM with EBSD. We will apply it first to the characterization of threading dislocations in Si/Si-Ge structures. As an initial step, we set out to detect the shift of the Kikuchi bands in EBSD patterns to sub-pixel precision.
In the standard analysis of EBSD patterns, to find the positions of Kikuchi bands, it is usual to use the Hough transform. This transform displays the intensity along all lines in the EBSD pattern, as a function of the position and the angle of the line. Thus linear features in the pattern (Figure 1) appears as peaks in the transform (Figure 2a). in normal EBSD analysis, the aim is to determine the orientation of the grain to a precision of perhaps a degree or two. Therefore, many simplifications are made in the software with the aim of gaining speed.
How Accurate is Qcbed ? -- the Case of Rutile (TiO2)
Authors: Jiang B , Friis J , Spence JCH 
Published: July 2020

Abstract
An accuracy of better than 1% is needed to measure the changes in charge density due to bonding. Here we report an accuracy up to 0.025% (random error) obtained in rutile crystal structure factors measurement by QCBED. This error is the standard deviation in the mean value obtained from ten data sets. Systematic errors may be present. Figure 1 gives an example of the (200) refinement results. Table 1 lists several low order structure factor refinement results. The accuracy of the measured electron structure factors was 0.1-0.2% but after conversion to x-ray structure factors, the accuracy for low orders improved due to the Mott formula [1] For (110) and (101) reflections, the accuracy in x-ray structure factors became 0.025% and 0.048% respectively. This accuracy is equivalent to that of the X-ray single crystal Pendellosung method on silicon crystals [2].
The experiments were done on a Leo 912 Omega TEM.
ProcessDiffraction VI.2: New possibilities in manipulating electron diffraction ring patterns
Authors: Lábár János L , Adamik Miklós 
Published: July 2020

Abstract
A free computer program was introduced recently to process electron diffraction ring patterns. The program (called ProcessDiffraction) produces XDR-like output from the digitized version of the measured diffraction patterns. The enhanced functionality of V1.2 is summarized in the present paper.
1. The program starts with a hint-window giving suggestions what can be done next. Hints change permanently as processing progresses. The hint-window can be switched off optionally. It is a complement to the Windows-style Help-system. 2. The center of the rings is found by manually shifting the measured pattern until it overlaps with a generated reference circle. The computer can further refine the position of the center. 3. Elliptical distortion of the measured pattern (NOT of the display, which is irrelevant) is corrected by adjusting the eccentricity and axis direction of the reference ellipse (distorted from the reference circle) until visually coincide with the measured ring.
Designing Advanced Ceramic Structures with Novel Environmental Microscopy and Related Methods
Authors: Gai Pratibha L 
Published: July 2020

Abstract
Silica and titania based ceramics and their analogs are some of the most fundamental in crystal chemistry and ceramic science Our interests include applications of nanostructures and chemical composites of the ceramics in nanoelectronics, chemical processes and as scaffolds in biotechnologies. Finely divided titania is used in a vast array of products including paper, paint, food and clothing. Novel microscopy methods including dynamic environmental-high resolution transmission EM (EHREM) at the atomic level, FESEM and cathodoluminescence are leading to striking progress in the development of the ceramic nanotechnologies.
Phase transformations in the cristobalite form of silica, from the tetragonal a phase (low or room temperature form) to the cubic β phase (high temperature, (270°C) form) result in discontinuous thermal expansion and are not conducive to nanotechnology. Here we report fundamental in situatomic resolution studies of the phase transformations using EHREM and have used the results to design a number of stable, single-phase structures at room temperature (RT).
Manipulation of Nanodiamond Clusters for Nanoscale Applications
Authors: Tyler T , Kvit A , Jaeger D , Zhirnov V , Hren J 
Published: July 2020

Abstract
One objective of the present work is to study the processes of assembly/self assembly of diamond clusters into nanostructures such as dots, wires,and filmsunder the influence of high electric fields. Diamond nanoparticles (∼2-5 nm in size) in a suspension of ethyl alcohol were deposited by pulsed electrophoresis onto sharp metal needles, such as those employed for field electron emission applications [1,2]. A custom designed sample holder has been constructed for a JEOL 2010 F, which allows for the convenient transfer of the sharp metal wires for analysis at high resolution, and then for removal (e.g. for re-deposition). These procedures allow us to precisely control the deposition thickness and morphology. They are capable of building a variety of deposition structures, even an isolated nanodiamond particle. The geometry of the deposits depends upon the applied voltage, the concentration of the suspension, the pulse duration, and the local electric field (which in turn depends on tip geometry, e.g. see Fig. 1).
Extreme SEM
Authors: Boyes E D 
Published: July 2020

Abstract
New analytical methods have been implemented with novel instrumentation designed to extend, to explore and to exploit an expanded performance envelop for high resolution imaging, EDX chemical microanalysis and chemical imaging with robust and representative bulk samples in a scanning electron microscope (SEM). A key contribution is the integrated and innovative design of the in-lens electron optics, sample holders, detectors including for EDX, specimen chamber and vacuum system. Each component has been improved individually over previous practice and they have been made to work together much better, especially with respect to combining advanced electron imaging at low voltages with efficient x-ray analysis and mapping.
Compared to a conventional out-of-lens/semi-in-lens FESEM the secondary electron image (SEI) resolution at the widely used low voltage of 1 kV is improved by a factor of almost 2x to &lt;1.5nm and this facilitates low voltage imaging at primary magnifications of 250,000x (Fig.1) or more.
Synthesis and Characterization of Carbon Nanotubes on Porous Silicon Substrates
Authors: Dong Lifeng , Jiao Jun , Tuggle David W , Foxley Sean 
Published: July 2020

Abstract
Carbon nanotubes have many unique properties, including a tensile strength greater than that of steel and current-carrying capacity greater than any known metal or superconductor. Many applications have been identified, including field-emission displays and ultra-small transistors. At present, the main barrier to such applications is the ability to synthesize the nanotubes in a large scale with controlled properties'.
The work reported here is an effort for growing carbon nanotubes on porous silicon with a designed pattern. Experimental procedures include (1) a liquid catalyst was prepared by mixing AlCl3.6H2O, SiCl4, FeCl3.6H2O, MoO2Cl2,P-123 chemical components; (2) a flat piece of polydimethylsiloxane (PDMS) elastomer stamp containing a designed pattern was etched in the oxygen plasma, followed by spin coating the catalyst on the patterned stamp;(3) the inked stamp was printed onto a porous silicon substrate. This substrate was then heated in air at 70°C for 10 minutes to stabilize the catalytic pattern on the surface of porous silicon.
Atomic Scale Analysis of a YSZ Bicrystal Grain Boundary
Authors: Lei Y , Ito Y , Browning N D 
Published: July 2020

Abstract
Yttria-stabilized zirconia (YSZ) has been the subject of many experimental and theoretical studies, due to the commercial applications of zirconia-based ceramics in solid state oxide fuel cells. Since the grain boundaries usually dominate the overall macroscopic performance of the bulk material, it is essential to develop a fundamental understanding of their structure-property relationships. Previous research has been performed on the atomic structure of grain boundaries in YSZ, but no precise atomic scale compositional and chemistry characterization has been carried out. Here we report a detailed analytical study of an [001] symmetric 24° bicrystal tilt grain boundary in YSZ prepared with ∼10 mol % Y2O3 by Shinkosha Co., Ltd by the combination of Z-contrast imaging and electron energy loss spectroscopy (EELS).
The experimental analysis of the YSZ sample was carried out on a 200kV Schottky field emission JEOL 201 OF STEM/TEM4.
Direct Observation of Single Displacement Cascade in Pyrochlore by Tv-Rate In-Situ TEM and Ex-Situ HRTEM
Authors: Lian J , Wang L M , Wang S X , Ewing R C 
Published: July 2020

Abstract
The ion irradiation-induced crystalline-to-amorphous transformation has been studied in many complex ceramics. Direct impact amorphization has been considered to be one of the fundamental amorphization mechanisms for complex ceramics under heavy ion irradiation. Based on the directimpact model, a highly energetic incident ion transfers its kinetic energy to the target as a thermal spike within 10“13 sec creating a “molten-like” displacement cascade, typically nanometer-scaled in diameter (as indicated by the result of a computer simulation in Fig. 1). This “molten” zone quickly quenches to a small amorphous domain within a few pico-seconds. Epitaxial recrystallization occurs around the amorphous/crystalline interface, so that the size of amorphous domains decrease with time. The accumulation and overlap of small amorphous domains eventually leads to complete amorphization of the irradiated material. Although the in-situTEM technique with the setup shown in Fig. 2 has been extensively applied to the study of the amorphization process in complex ceramics, most of the previous studies relied on in-situobservation of the electron diffraction pattern, and there has been a lack of solid evidence of direct impact amorphization due to the small nature of the cascades and the rapid kinetics of its evolution.
Surface Steps on Flux-Grown Alumina
Authors: Ravishankar N , Barry Carter C 
Published: July 2020

Abstract
The utility of a surface to serve as a substrate depends upon its surface structure. The presence of steps on the surface affects the quality of the deposited material. The basal surface of alumina is one of the most widely used substrate materials and hence considerable effort has been directed towards the study of this surface. The mechanism of formation of a stepped structure on the basal surface of alumina has been investigated using atomic force microscopy. The evolution of steps on the basal surface as a function of temperature has been reported. Flux growth is an attractive route for producing alumina because of the low temperatures required for processing and the extremely low dislocation densities that can be obtained. in the present study, the structure of steps on flux-grown alumina has been investigated. Formation of low-index macrofacets as a result of crystal growth has been observed.
Electron Microscopy in Optimizing Microstructure and Mechanical Properties of Hot-Pressed Silicon Carbide
Authors: Zhang XF , Sixta ME , Yang Q , Chen D , Ritchie RO , De Jonghe LC 
Published: July 2020

Abstract
SiC, as one of the most promising candidate ceramics for high temperature structural applications, offers many intrinsic advantages, including high melting temperatures, low density, and high elastic modulus. However, the use of SiC to date has been severely limited by its poor fracture toughness (∽ 2-3 MPa√m for commercially available materials) and crack-growth resistance. Our study focuses on the development of silicon carbide as a potentially tough, high-temperature, and damage-tolerant material. The approaches include identifying roles of sintering additives in modifying grain morphology, effects of post-annealing on grain boundary phases, and possibility in introducing nanoscale precipitates in SiC grains. Central in these efforts is structural characterization using state-of-the-art electron microscopy.
The first success was in situtoughening the SiC, by hot pressing in the presence of A1, B and C additions. Elongated and interlocked grains were developed surrounded by an Al-containing amorphous grain boundary film.