bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Mechanism for Mechanochemical Wear of Model Systems: Nano-Tribology Studies of Carbonate and Phosphate Single Crystal Surfaces in Aqueous Media
Authors: Dickinson JT , Scudiero L , Park NS , Kim MW , Langford SC 
Published: July 2020

Abstract
In several mechanical wear situations, e.g., those involving biomaterials and applications of mechanochemical polishing, a surface experiences simultaneous tribological loading and corrosive chemical exposure; the combination can greatly increase wear rates. We examine the exposure of single crystal calcite [CaCO3], dolomite [MgCa(CO3)2], and brushite[CaHPO4.2H2O] to buffered aqueous solutions and mechanical stimulation with an Scanning Force Microscope (SFM) tip. Silicon nitride tips are used with applied normal loads from 0-300 nN, tip radii ∼30 nm and tip velocities from 1-200 μm/s. We present the influence of normal force, tip velocity, and solution chemistry on the rates of corrosive wear of calcite and dolomite. Images of the wear of atomic steps can be used to examine the wear rates and propagation of dissolution around the stimulated region. Mechanical stimulation includes small area scans, linear reciprocation, and indentation. A diagram of wear by linear reciprocation of the SFM tip and typical results on single crystal calcite are shown in Figs. 1 and 2, respectively.
The High Temperature Material Laboratory: A National User Facility For Advanced Materials Characterization
Authors: Allard L F , Nolan T A , Pasto A E 
Published: July 2020

Abstract
The High Temperature Materials Laboratory (HTML, Fig. 1) is a national resource for materials characterization sponsored by the Department of Energy’s Office of Transportation Technology, Assistant Secretary for Energy Efficiency and Renewable Energy. The HTML comprises six principal user centers: Materials Analysis, Thermophysical Properties, X-ray and Neutron Diffraction, Mechanical Characterization and Analysis, Residual Stress, and Machining and Inspection Research. Instruments available at the user centers have extensive capabilities for characterizing the microstructure, microchemistry, and physical and mechanical properties of materials over a wide range of temperatures. Details of all the capabilities of the various user centers are available on the World Wide Web at http://www.ms.ornl.gov/htmlhome/default.htm.http://www.nice.org.uk/page.aspx?o=43210
To date, more than 300 different institutions, evenly divided between university and industry, have formal research agreements with the HTML. Three separate programs are available to meet the needs of these users as well as those from federal agencies wishing to gain access to the HTML.
Magnetism And Micro Structure: Advances In Electron-Optical Characterization
Authors: Krishnan Kannan M 
Published: July 2020

Abstract
Tremendous progress has been made in the field of magnetic materials research and technology over the past few years. Superior properties and novel scientific questions arise due to our ability to either synthesize artificial structures or to tailor microstructures at the appropriate length scales. Microstructure, generally defined as the morphological arrangement of crystallites with similar or different phase constitutions and of the crystal defects, is controlled by the processing, which in turn affects the phases present, their topology and their dispersion. There are two key length scales that determine the magnetic behavior of materials. One is the characteristic length scale associated with the dimensional characteristics of the magnetic phenomenon under consideration. The second is the size of the microstructural feature of interest - grain size, shape, isolation, interfaces, inter-granular phases etc. It is important to identify the range where these two length scales overlap, for it is there that novel properties and phenomenon are usually observed.
Microstructure Of Fe-Nd-B Alloys Tailored To Approach Theoretical Coercrvtty Limits
Authors: Krishnan Kannan M , Girt Er , Nelson E C , Thomas G , Hofer Ferdinand 
Published: July 2020

Abstract
Performance of permanent magnets for a variety of applications is often determined by the maximum energy product (BH)max. In order to obtain high (BH)max permanent magnetic materials have to have large coercivity. In theory the coercive field of ideally oriented, non-interacting, single domain, magnetic particles, assuming Kl is much bigger than K2, was shown to be He = 2K1/Ms - N Ms, where Kl and K2 are the magnetocrystalline anisotropy constants, Ms is the spontaneous magnetization and N is the demagnetization factor. For randomly oriented non-interacting particles the Stoner-Wohlfarth model predicts that the value of Hc decreases to about half. However, experimentally obtained values of the coercitive fields in permanent magnets are 3 to 10 and 2 times smaller for well oriented and randomly oriented samples, respectively. This discrepancy was attributed to inter-particle interaction and the microstructure of the permanent magnets. In order to understand the difference between the theoretically predicted and experimentally obtained results for He we prepared rapidly quenched, Nd-rich, NdxFe14B (2 &lt; x &lt; 150) ribbons.
Lorentz And Interference Electron Microscopy On A Scanning Tem
Authors: Yajima Y , Takahashi Y 
Published: July 2020

Abstract
Magnetic imaging can be performed both on conventional (projection) and scanning TEM (CTEM/STEM). The CTEM-based magnetic imaging, classified into Fresnel, Foucault, holography, and other modes, has proven successful by now in observing various magnetic objects, and has accordingly been well documented elsewhere. The STEMbased one has emerged relatively recently prompted by the rapid growth of current STEM technology.
The most ubiquitous implementation of Lorentz microscopy on a STEM is the differential phase contrast (DPC) mode. Each scanning signal obtained in the DPC mode is linear to Lorentz deflection, thus reflects the magnitude of an in-plane component of magnetic induction integrated along the optical axis(Fig.l). The signals therefore suffice to generate integrated in-plane magnetic induction maps(Fig.2). Furthermore, by making use of the fact that the Lorentz deflection distribution across the image plane forms an irrotational (vortex-free) 2D vector field, a pertinent numerical image processing yields a function equivalent to the electron phase function representing magnetically distorted electron wavefront.
Scanning Electron Microscopy With Polarization Analysis (Sempa) Investigations Of Multilayer Magnetism
Authors: J. Unguris  , Celotta R J , Pierce D T 
Published: July 2020

Abstract
Mulitlayers consisting of various combinations of 1-10 nm thick ferromagnetic, antiferromagnetic and nonmagnetic films have numerous applications in magnetic recording, non-volatile data storage, and sensor technologies. One key aspect to understanding how these devices work is being able to image their magnetic structure. SEMPA is well suited for this job, because of its surface sensitivity and compatibility with thin film growth and surface analysis techniques. This talk will review the SEMPA technique and describe thep use of SEMPA in two examples; one in which the magnetization is imaged while growing a multilayer, and another which examines the magnetization while depth profiling a multilayer by ion milling.
A SEMPA investigation of the magnetic exchange coupling in an Fe/Cr/Fe sandwich is shown in Figs. 1 and 2. A wedge shaped Cr interlayer was grown as shown in Fig. 1 in order to measure the Cr thickness dependence of the exchange coupling.
The Use Of Encoders To Improve Both The Spectral And SpatialPrecision M Raman Microscope Mapping Experiments
Authors: Whitley Andrew , Bennett Bob , Smith Brian 
Published: July 2020

Abstract
With the introduction of high efficiency short acquisition time Raman microscopes at the beginning of the 1990's Raman mapping experiments became more realistic for many different materials. Previous to this time Raman maps of any useful size would take far too long for all but the strongest of Raman scatterers. A typical Raman spectrum used to take 30 minutes or more, a relatively small map of 50μ × 50μ using a step size of 1μ, would take over 50 days to acquire. Today the same map can be obtained in less than 4 hours. The use of an xyz mapping stage in conjunction with a Raman microscope is now common. The user defines an area on the sample that requires mapping and selects a step size and spectral acquisition time. Once the experiment is started the mapping stage drives the sample to the start position and takes the first spectrum, once this is completed the sample is moved by the requested step size and the next spectrum is measured.
Relative Raman Intensity Calibration Through Fluorescent Glass Standards
Authors: Etz Edgar S , Hurst Wilbur S , Choquette Steven J , Blackburn Douglas H 
Published: July 2020

Abstract
Attention has been given in the recent past to the various issues that arise from the general lack of standardized procedures for the calibration of Raman spectral intensity. With the increasing acceptance of analytical Raman methods and the availability of diverse types of commercial Raman systems, it becomes increasingly important that uniform calibration methods be developed that provide some means for the correction of the Raman instrument response function. As matters stand now, Raman spectra are typically not corrected for instrument-dependent variations in spectrometer sensitivity across the Raman range. Especially for measurements at different excitation wavelengths, this leads to often severe distortion of relative peak intensities which impedes calibration transfer and affects spectral matching in library search routines. These issues have been brought forth by the McCreery group to the point where national standards organizations (e.g., ASTM, NIST), federal regulatory agencies, the Raman instrument manufacturers, and the analytical Raman community, have taken note.
A Method For Analysis Of Clinical Tissue Samples Using Ft-Ir Microspectroscopic Imaging
Authors: Story Gloria M , Marcott Curtis , Dukor Rina K 
Published: July 2020

Abstract
During the past decade, Fourier transform infrared (FT-IR) microspectroscopy has been used successfully in many studies to differentiate normal and diseased tissue samples obtained from a variety of organs, including colon, cervix, prostate, and breast. IR images were constructed by collecting spectra point-by-point using a mapping stage on a FT-IR microscope equipped with a single-element detector. Five years ago, in collaboration with NIH scientists Dr. Neil Lewis and Dr. Ira Levin, Procter and Gamble researchers developed a technique for performing vibrational spectroscopic imaging microscopy using a liquid-nitrogen-cooled focal-plane array (FPA) detector and a step-scanning FT-IR spectrometer coupled to a refractive microscope. With this configuration, equipped with a new 64-pixel x 64-pixel Mercury-Cadmium-Telluride (MCT) FPA detector, we are able to image an 800-μm x 800-μm area of a specimen without moving the sample.
For all of these IR imaging studies, the tissue samples were prepared in a manner that was special and different from that commonly used in a pathology laboratory, i.e.,the histopathology sample was not identical to the spectroscopic sample.
A New Model For Electron Probe Quantification
Authors: Donovan John J , Pingitore Nicholas E , Jeanloz Raymond 
Published: July 2020

Abstract
Castaing’s first approximation assumes that the characteristic radiation emitted by each element in a compound is unaffected by the presence of the other elements, and that the intensity of the radiation emitted by each element in the compound is proportional to its mass concentration. From Castaing’s first approximation based on mass fractions, the initial estimate of the concentration of an element in a compound is

where C and C° are mass fractions in the sample and standard, and I and I° are x-ray emission intensities of a specific transition measured in the sample and the standard. Surprisingly, the mass fraction approach works well in practice, even though it lacks any obvious physical basis. This can be understood by considering that for typical energies involved in EPMA (50 keV or less), the size of the nucleus is several orders of magnitude smaller than the average incident beam electron wavelength.
Quantitative Electron Microprobe Analysis Of Semiconductor Materials: An Evaluation Of Accuracy
Authors: Carpenter PK 
Published: July 2020

Abstract
Both precision and accuracy are central to quantitative microanalysis. While precision may be evaluated from x-ray counting statistics and replicate measurement, the determination of analytical accuracy requires well characterized standards of which there are few that span a wide range of compositions in binary and ternary systems. The accuracy of silicate mineral analysis has been previously studied via measurement of α factors at multiple accelerating potential and the subsequent evaluation of correction algorithms and mass absorption coefficient (mac) data sets. This approach has been extended in this study to the In2O3-Ga2O3 and HgTe-CdTe systems.
Single crystals of ln2O3, Ga2O3, and an InGa-oxide of unknown composition were used to evaluate accuracy in the In2O3-Ga2O3 binary, using the GaKα, GaLα, and InLα x-ray lines, with WDS measurements performed at 15, 20, and 25KV relative to the ln2O3 and Ga2O3 standards (see Table I). The Ga Kα line exhibits minimal absorption, has no fluorescence correction in this system and is not critically dependent on the correction algorithm or mac data set used.
Parallel Monte Carlo Simulation Using Desktop Computers
Authors: Scott John Henry J , Myklebust Robert L , Newbury Dale E 
Published: July 2020

Abstract
Monte Carlo simulation of electron scattering in solids has proven valuable to electron microscopists for many years. The electron trajectories, x-ray generation volumes, and scattered electron signals produced by these simulations are used in quantitative x-ray microanalysis, image interpretation, experimental design, and hypothesis testing. Unfortunately, these simulations are often computationally expensive, especially when used to simulate an image or survey a multidimensional region of parameter space.
Here we present techniques for performing Monte Carlo simulations in parallel on a cluster of existing desktop computers. The simulation of multiple, independent electron trajectories in a sample and the collateral calculation of detected x-ray and electron signals falls into a class of computational problems termed “embarrassingly parallel”, since no information needs to be exchanged between parallel threads of execution during the calculation. Such problems are ideally suited to parallel multicomputers, where a manager process distributes the computational burden over a large number of nodes.
The New Form Of The Zeta-Factor Method For Quantitative Microanalysis In Aem-Xeds And Its Evaluation
Authors: Watanabe M , Williams D B 
Published: July 2020

Abstract
For quantitative thin-film microanalysis using X-ray energy dispersive spectrometry (XEDS) in analytical electron microscopy (AEM) the Cliff-Lorimer ratio technique is widely applied. One of the critical steps in the ratio technique is to determine the aiff-Lorimer k factor relating the characteristic X-ray intensities to the compositions. The k factor can be determined experimentally with the relative error of ˜ ± 1%. So, the most accurate quantification can be performed using the experimental k factors. To determine the k factors experimentally, standard thin-filrns with known composition are required. Unfortunately, this is not always possible because such the standards may not be available. Even if all standards are available, many k factors should be determined in multi-component system. This is time consuming. These limitations in k-factor determination make thin-film quantification harder. This paper presents a new quantitative procedure for thin specimens to overcome these limitations.
Multiprobe Studies Of Interfaces In Complex Crystals Using Advanced Electron Microscopy
Authors: Zhu Yimei , Wu L , Volkov VV 
Published: July 2020

Abstract
The small probe size and high spatial resolution of TEM offer unique capabilities for studying interfaces of materials. Compared with neutron and x-ray diffraction, TEM is often considered nonquantitative. In HREM, especially, atomic images can alter significantly with imaging parameters that are often difficult to determine experimentally. The weakness of the HREM can be circumvented by a multiprobe approach, i.e., the combined use of a wide range of TEM techniques, such as B-F/D-F imaging, nano-probe EDS and EELS, electron diffraction, and strain-field characterization. Quantitative analysis, based on the calculations and experimental TEM data, is often necessary to correctly derive the crystal-, chemical-, and electronic-structure of an interface.
We review our multiprobe approach in studying interfaces in complex systems of superconductors, starting with the simplest interface, twin boundary, in YBa2Cu3O7-δ. Although HREM suggested that there are two types of twin boundaries, with and without a ˜d110 lattice translation at the boundaries, the structural characteristics of the interfaces were determined by analyses of the interfacial δ-α fringe and the associated diffuse scattering, while EELS revealed their association with the local oxygen/hole concentration.
Dynamics Of Grain Boundary Space-Charge Potential In Electroceramics
Authors: Johnson Kevin D , Dravid Vinayak P 
Published: July 2020

Abstract
A large number of bulk and thin-film electroceramic systems contain electrically active interfaces which dictate the various useful electronic properties of these devices. The electrical activity of these interfaces stems from a complex interplay among various interfacial attribute but often involves formation of some form of electrostatic potential at the interfaces which is modified under applied bias of current and/or voltage.
Figure la schematically shows charge distribution at a model grain boundary (GB), while Figure 1(b) shows its corresponding potential distribution. As shown in Figure 1(c), the energy band structure bends opposite to this built-in potential, causing a downward shift at the grain boundary. The difficulty with evaluating the Schottky barrier model, which is often invoked to explain GB electrical activity, is that the charge density distribution and therefore the band bending is expected to dynamically alter as bias is applied across the grain boundary. This variation adds another level of complexity to theoretical descriptions of the barrier behavior
Hrem Of General And Twist Grain Boundaries
Authors: Merkle K L , Thompson L J 
Published: July 2020

Abstract
The observation of atomic-scale structures of grain boundaries (GBs) via axial illumination HREM has been largely restricted to tilt GBs, due to the requirement that the electron beam be parallel to a low-index zone axis on both sides of the interface. This condition can be fulfilled for all tilt GBs with misorientation about a low-index direction. The information obtained through HREM studies in many materials has brought important insights concerning the atomic-scale structure of such boundaries. However, it is well known that tilt GBs occupy only an infinitesimally small fraction of the 5-dimensional phase space which describes the macroscopic geometry of all GBs. Therefore, although tilt GBs are very important due to their low energy, it would be usefulto also study twist GBs and general GBs that contain twist and tilt components.
We have prepared thin-film Au samples by an epitaxy technique in which (01l) and (001) grains are grown side by side.
Structural Determination Of A Novel Defect In SrBi2Ta2O9 Using Atomic-Resolution Z-Contrast Imaging
Authors: Yan Y , Xu Z , Lu X , Viehland D , Al-Jassim MM , Pennycook S J 
Published: July 2020

Abstract
Ferroelectric thin films have received much attention because of their nonvolatile ferroelectric random access memory (NVFRAM) applications. Recently SrBi2Ta2O9 (SBT), a bismuth-layered ferroelectric compound, has been recognized as a leading candidate for the NVFRAM applications because of its negligible fatigue, low leakage currents and ability to maintain bulk characteristics when fabricated in very thin films. While most work up to date has been focused on its thin film forms for nonvolatile memory applications, its intrinsic properties, basic structure and the effects of defects on the properties are not well understood, mainly due to the lack of sizable single crystals and the details of defects. In this paper we report the first direct determination of a novel planar defect structure in SrBi2Ta2O9, using high-resolution Z-contrast imaging.
Atomic Structure Of Epitaxial Thin Films Of The Srn+1tinO3n+1 Ruddlesden-Popper Homologous Series
Authors: Tian W , Jiang J C , Pan X Q , Haeni J H , Schlom D G 
Published: July 2020

Abstract
The n+1TinO3n+1 Ruddlesden-Popper homologous series are promising candidates in the search for low loss tunable dielectric materials. SrTiO3 (n=∞) has the perovskite structure with alternating TiO2 and SrO layers. However, those members of the n+1TinO3n+1 series with n≠∞ have tetragonal symmetry and space group 14/mmm. These phases are formed by inserting a rock-salt SrO layer every n SrTiO3 perovskites, resulting in a successive perovskite blocks being mutually sheared by [1/2,1/2,0] (Fig. 1).
Previously, the n = 1 - 3 members of this series have been made in polycrystalline form using solid state synthesis methods. Attempts to synthesize intermediate members (4≤n&lt;∞) have been unsuccessful and resulted in mixed phase samples. Fortunately, significant advancement in epitaxial growth techniques makes it possible to control the synthesis of a wide variety of homologous oxide crystal systems. In the present work, thin films of the Srn+1TinO3n+1, RP series with n = 1 - 5 have been synthesized using reactive molecular beam epitaxy (MBE).
3d Mapping Of Light-Element Segregation In 316 Stainless Steel By Atom Probe
Authors: Kelly T F , Larson D J , Miller M K , Flinn J E 
Published: July 2020

Abstract
A vanadium-bearing variant of 316 stainless steel that was rapid solidification processed (RSP) by gas atomization and hot extrusion of the powder (10:1 extrusion ratio at 900°C) has been studied previously by conventional atom probe field ion microscopy (APFIM). The mechanical properties of this steel were markedly improved by RSP and aging (600°C for 1000 hours). High nitrogen (0.45 at% (0.2 wt%)) and oxygen (0.16 at% (0.05 wt%)) contents were intentionally introduced by melting under 80% nitrogen/20% oxygen gas and atomizing in nitrogen gas. A nominal boron concentration of 0.04 at% (0.01 wt%)) is present as a tramp element. As a result, a large number density (˜ 2 × 1021 m-3) of 25 nm plate-like vanadium-rich nitrides precipitate during aging of the alloy and these precipitates contribute a major portion of the strengthening. Previous efforts to locate the oxygen in the structure using APFIM were inconclusive largely due to poor counting statistics.