Understanding how nanoscale heterogeneities influence charge transport and mass transfer in oxides is critical for developing advanced materials for energy and electronic uses. In high-temperature applications, the formation of thermal oxides with complex chemical and structural features plays a central role in material lifetime. While thermally grown zirconia (ZrO2) on zirconium alloys exhibits strong chemical and microstructural gradients across the oxide thickness, linking these heterogeneities to electronic-defect landscapes remains challenging. We demonstrate cross-sectional scanning electron microscope-cathodoluminescence (SEM-CL) as a mesoscale probe of spatial variations in luminescence in zirconia and establish correlations with co-registered electron backscatter diffraction (EBSD) and electron probe micro-analysis (EPMA) on the same region. The SEM-CL signal is dominated by the ~2.7 eV defect band, but its intensity varies strongly across the oxide cross section. Correlative EBSD-CL analysis reveals that CL intensity increases with grain area and decreases at the grain boundaries, consistent with enhanced non-radiative recombination associated with microstructural disorde
The alterations in the magnetic properties and electronic structure of chemical vapor deposition (CVD) grown nano-dimensional molybdenum disulfide (MoS2) after low energy ion irradiation are thoroughly investigated. The formation of pure hexagonal 2-H phase has been identified by Raman spectroscopy and X-ray diffraction (XRD). The pristine samples are irradiated by Argon (Ar) ions with low energy at different fluences. A comprehensive analysis of Raman spectroscopy data manifests the formation of lattice defects like S-vacancies across the samples after irradiation. Triangular-flake formation in the pristine sample is confirmed by field emission scanning electron microscopy (FESEM) images. After increasing irradiation fluences the big flakes commenced to fragment into smaller ones enhancing the number of edge-terminated structures. The electron probe microanalyzer (EPMA) analysis verifies the absence of any magnetic impurity. Rutherford backscattering spectrometry (RBS) and X-ray photoelectron spectroscopy (XPS) study confirm the formation of S-vacancies after irradiation. The pristine sample exhibits diamagnetic behavior at room temperature. The saturation magnetization value incr
We have carried out a SEM-EPMA-TEM study to determine the textures and compositions of relict primary iron sulfides and their alteration products in a suite of moderately to heavily-altered CM1 carbonaceous chondrites. We observed four textural groups of altered primary iron sulfides: 1) pentlandite+phyllosilicate (2P) grains, characterized by pentlandite with submicron lenses of phyllosilicates, 2) pyrrhotite+pentlandite+magnetite (PPM) grains, characterized by pyrrhotite-pentlandite exsolution textures with magnetite veining and secondary pentlandite, 3) pentlandite+serpentine (PS) grains, characterized by relict pentlandite exsolution, serpentine, and secondary pentlandite, and 4) pyrrhotite+pentlandite+magnetite+serpentine (PPMS) grains, characterized by features of both the PPM and PS grains. We have determined that all four groups were initially primary iron sulfides, which formed from crystallization of immiscible sulfide melts within silicate chondrules in the solar nebula. The fact that such different alteration products could result from the same precursor sulfides within even the same meteorite sample further underscores the complexity of the aqueous alteration environme
We meticulously study the individual effects of hydrogen irradiation and annealing on the electronic structure and magnetic properties of nanostructured MoS2 thin films grown through Chemical Vapor Deposition (CVD). The role of edge-terminated structure and point defects to induce room-temperature ferromagnetism (RTFM) is thoroughly investigated. The nanostructured pristine MoS2 thin films show the formation of a pure 2-H MoS2 phase, confirmed by X-ray diffraction (XRD) and Raman spectroscopy. Pristine MoS2 thin films are independently annealed in a reducing hydrogen environment and irradiated with low-energy hydrogen ions to study the significance of point defects like sulfur vacancies. RTFM with saturation magnetization value (Ms: 1.66 emu/g) has been observed in the pristine film. Magnetization increases after irradiation and annealing processes. However, hydrogen annealing at a temperature of 200oC exhibits a maximum Ms value of 2.7 emu/g at room temperature. The increase in ferromagnetism is attributed to an increment in sulfur vacancies, hydrogen adsorption with sulfur, and modification in edges, which is confirmed by the analysis of Electron probe micro-analyzer (EPMA), X-ra
Over the Nullarbor Plain in South Australia, the Desert Fireball Network detected a fireball on the night of 1 June 2019 (7:30 pm local time), and six weeks later recovered a single meteorite (42 g) named Arpu Kuilpu. This meteorite was then distributed to a consortium of collaborating institutions to be measured and analyzed by a number of methodologies including: SEM-EDS, EPMA, ICP-MS, gamma-ray spectrometry, ideal gas pycnometry, magnetic susceptibility measurement, μCT, optical microscopy, and accelerator and noble gas mass spectrometry techniques. These analyses revealed that Arpu Kuilpu is an unbrecciated H5 ordinary chondrite, with minimal weathering (W0-1) and minimal shock (S2). The olivine and pyroxene mineral compositions (in mol%) are Fa: 19.2 +- 0.2, and Fs: 16.8 +- 0.2, further supporting the H5 type and class. The measured oxygen isotopes are also consistent with an H chondrite (δ17O = 2.904 +- 0.177; δ18O = 4.163 +- 0.336; Δ17O = 0.740 +- 0.002). Ideal gas pycnometry measured bulk and grain densities of 3.66 +- 0.02 and 3.77 +- 0.02 g cm-3, respectively, yielding a porosity of 3.0 % +- 0.7. The magnetic susceptibility of this meteorite is log X = 5.16 +- 0.08. The m
The reductive perturbation approach was used to explore the nonlinear propagation of fast (compressive) and slow (rarefactive) electron-position (EP) magneto-acoustic (EPMA) modes in an EP plasma medium. The solitary wave solution of the Korteweg-de Vries (K-dV) equation is used to identify the basic properties of EP compressional Alfvén waves. It is shown that the fast (slow) EPMA mode is predicted to propagate as compressive (rarefactive) solitary waves. The basic features (i.e., speed, amplitude, and width) of the compressive (i.e., fast) EPMA waves are found to be completely different from those of rarefactive (i.e., slow) EPMA ones. It is also examined that hump (dip) shape solitary waves are found for fast (slow) mode. The significance of our findings is in understanding the nonlinear electromagnetic wave phenomena in laboratory plasma and space environments where EP plasma may exist.
Single crystals of non-centrosymmetric $s$-wave superconductor LaPt$_{0.88}$Si$_{1.12}$ have been grown by the Czochralski (Cz) technique, whose crystal structure is described by the space group $I4{_1}md$ at ambient conditions. The inter-site mixing between platinum and silicon is confirmed by both single-crystal x-ray diffraction (SXRD) and electron probe micro-analyzer (EPMA). The disordered material exhibits a lower superconducting (SC) transition temperature $T_c$ at 2.02 K as opposed to the highest value of 3.9 K reported in polycrystalline LaPtSi without inter-site mixing. From specific heat, the Sommerfeld coefficient ($γ$) is estimated to be 7.85 mJ/mol K$^2$, which is much larger than the values reported for the samples exhibiting higher $T_c$. This is unprecedented as $T_c$ seems to decrease with increase in the electron density of states (DOS) at the Fermi energy and thus $γ$. The present work reports on the anomalous behaviour of SC and normal state properties of LaPt$_{x}$Si$_{2-x}$, presumably caused due to the existence of non-trivial topological bands.
Spatially-resolved studies of a YBaCuO thin film bridge using electron probe microanalysis (EPMA), low-temperature scanning electron microscopy (LTSEM), and magneto-optical flux visualization (MO) have been carried out. Variations in chemical composition along the bridge were measured by EPMA with 3 microns resolution. Using LTSEM the spatial distributions of the critical temperature, Tc, and of the local transition width, dTc, were determined with 5 microns resolution. Distributions of magnetic flux over the bridge in an applied magnetic field have been measured at 15 and 50 K by magneto-optical technique. The critical current density Jc as a function of coordinate along the bridge was extracted from the measured distributions by a new specially developed method. Significant correlations between Jc, Tc, dTc and cation composition have been revealed. It is shown that in low magnetic fields deviation from the stoichiometric composition leads to a decrease in both Tc and Jc. The profile of Jc follows the Tc-profile on large length scales and has an additional fine structure on short scales. The profile of Jc along the bridge normalized to its value at any point is almost independent
Formation of femtosecond laser direct-written positive refractive index waveguides in Gallium Lanthanum Sulphide (GLS) glass is explained for the first time. Evidence of structural changes and ion migration are presented using Raman spectroscopy and electron probe microanalysis (EPMA), respectively. 2-D Raman spectra maps reveal a peak shift and full-width at half maximum variations in the symmetric vibrations of GaS4 main band. For the first time, the 2D map of the boson band was successfully used to identify and understand the material densification profile in a high refractive index glass waveguide. Finally EPMA provided the evidence of ion migration due to sulphur and the observation of an anion (S2-) migration causing material modification is also reported for the first time.
Atom probe tomography (APT), electron probe microanalysis (EPMA) and nanoindentation were used to characterise the oxygen-rich layer on an in-service jet engine compressor disc, manufactured from the titanium alloy TIMETAL 834. Oxygen ingress was quantified and related to changes in mechanical properties through nanoindentation studies. The relationship between oxygen concentration, microstructure, crystal orientation and hardness has been explored through correlative hardness mapping, EPMA and electron backscatter diffraction (EBSD). The role of microstructure on oxygen ingress has been studied and oxygen ingress along a potential alpha/ beta interface was directly observed on the nanoscale using APT.
Nanocrystalline n-AlN:Er thin films were deposited on (001) Silicon substrates by r. f. magnetron sputtering at room temperature to study the correlation between 1.54 $μ$m IR photoluminescence (PL) intensity, AlN crystalline structure and Er concentration rate. This study first presents how Energy-Dispersive Spectroscopy of X-rays (EDSX) Er Cliff Lorimer sensitivity factor alpha = 5 is obtained by combining EDSX and electron probe micro analysis (EPMA) results on reference samples. It secondly presents the relative PL intensities of nanocrystallized samples prepared with identical sputtering parameters as a function of the Er concentration. The structure of crystallites in AlN films is observed by transmission electron microscopy.
We have investigated the preparation and bulk magnetic properties of NaxCoO2 in the range 0.5<x<0.95, including those for single crystals grown by the floating-zone method in an image furnace. To characterize the samples and ascertain their quality we performed x-ray powder diffraction, electron-probe microanalysis (EPMA) and magnetization measurements. Based on our findings we are able to report conditions for the preparation of single-phase polycrystalline and single-crystal samples in the range 0.65<x<0.95. For lower concentration samples, however, i.e. x<0.65, residual Co3O4 impurities above the detectable limit remained, and conditions to eliminate this have still to be identified. Investigations of the anisotropic magnetization of NaxCoO2 single crystals show: (i) transitions at ~320 K, ~275K and ~22 K present for all Na doping levels investigated, (ii) a strong increase in magnetization below ~8 K, (iii) a crossover in sense for the anisotropy around 8-10 K, and (iv) a hysteresis in the magnetization for certain Na doping levels at temperatures below ~15 K. Notably, neither of the high temperature anomalies (275 K, 320 K) could be observed in the powder sample
Boron carbide thin films were synthesised by laser-assisted chemical vapour deposition (LCVD), using a CO2 laser beam and boron trichloride and methane as precursors. Boron and carbon contents were measured by electron probe microanalysis (EPMA). Microstructural analysis was carried out by Raman microspectroscopy and glancing incidence X-ray diffraction (GIXRD) was used to study the crystallographic structure and to determine the lattice parameters of the polycrystalline films. The rhombohedral-hexagonal boron carbide crystal lattice constants were plotted as a function of the carbon content, and the non-linear observed behaviour is interpreted on the basis of the complex structure of boron carbide. Keywords: Boron carbide; Laser CVD; crystallographic structure; micro-Raman spectroscopy.
The microstructural development in H13 tool steel upon nitriding by an ion beam process was investigated. The nitriding experiments were performed at a relatively low temperature of about 400°C and at constant ion beam energy (400 eV) of different doses in a high-vacuum preparation chamber; the ion source was fed with high purity nitrogen gas. The specimens were characterized by X-ray photoelectron spectroscopy (XPS), electron probe microanalysis (EPMA), scanning and transmission electron microscopy (SEM and TEM), and grazing incidence and Bragg-Brentano X-ray diffractometry. In particular, the influence of the nitrogen surface concentration on the development of the nitrogen concentration-depth profile and the possible precipitation of alloying element nitrides are discussed.
The present study investigates the partial substitutions of Mn and Cu for Fe in the TiFe-system to gain better understanding of the role of elemental substitution on its hydrogen storage properties. The TiFe0.88-xMn0.02Cux (x = 0, 0.02, 0.04) compositions were studied. From X-Ray Diffraction (XRD) and Electron Probe Micro-Analysis (EPMA), it was found that all alloys are multi-phase, with TiFe as a major phase, together with \b{eta}-Ti and Ti4Fe2O-type as secondary precipitates, of all them containing also Mn and Cu. Increasing the Cu content augments the secondary phase amounts. Low quantity of secondary phases helps the activation of the main TiFe phase for the first hydrogen absorption, but on increasing their amounts, harsher activation occurs. Both Mn and Cu substitutions increase the cell parameter of TiFe, thus decreasing the first plateau pressure. However, Cu substitution rises the second plateau pressure revealing the predominancy of electronic effects associated to this substitution. All samples have fast kinetics and high hydrogen capacity making these substituted compounds promising for large scale stationary applications.
Results on the chemical composition, structure and growth kinetics of titanium nitride (TiN) films deposited on mild steel substrates by pyrolytic laser-induced chemical vapour deposition (LCVD) are presented. Golden coloured lines of TiN were deposited from a reactive gas mixture of TiCl4, N2 and H2 using a continuous wave TEM00 CO2 laser beam as heat source. The chemical composition and structure of the films were determined by electron probe microanalysis (EPMA) and glancing incidence X-ray diffraction (GIXRD). A non-contact laser profilometer was used to measure the thickness profiles of the films. Using the data obtained in the steady-state region of the TiN laser-written lines, growth rates in the range 3.7 to 6.9 micrometers per second were deduced. The Arrhenius relation between the deposition rate and the deposition temperature yields an apparent activation energy of 46.9(+-)3.8 kJ.mol-1. This result enabled us to conclude that under our deposition conditions the LCVD of TiN is controlled by mass transport in the vapour phase. Keywords: Coatings; Titanium nitride (TiN); Laser chemical vapour deposition (LCVD); Growth mechanisms.
A method is presented for the registration and correlation of intrinsic property maps of materials, including data from nanoindentation hardness, Electron Back-Scattered Diffraction (EBSD), Electron Micro-Probe Analysis (EPMA). This highly spatially resolved method allows for the study of micron-scale microstructural features, and has the capability to rapidly extract correlations between multiple features of interest from datasets containing thousands of datapoints. Two case studies are presented in commercially pure (CP) titanium: in the first instance, the effect of crystal anisotropy on measured hardness and, in the second instance, the effect of an oxygen diffusion layer on hardness. The independently collected property maps are registered us-ing affine geometric transformations and are interpolated to allow for direct correlation. The results show strong agreement with trends observed in the literature, as well as providing a large dataset to facilitate future statistical analysis of microstructure-dependent mechanisms.
The present work critically investigates the influence of low melting glasses on the fabrication of metal contacts, with the goal of advancing applications of bismuth based oxide glass and screen printed silver contacts for use in integrated circuits (ICs), solar cells, and sensors. In this study, novel electrode contacts were fabricated by screen printing composite pastes composed of mainly silver powder, Bi2O3 glass powder, and acyclic binder, and then firing the pastes in a belt furnace. The microstructures of the composite films after firing at 830 to 890 °C were observed under different corrosion conditions, and the resulting layers were analyzed with X ray diffraction (XRD) and the transfer length method (TLM). A series of investigations to determine the influence of Bi2O3 glass in silver paste involved various tests, including differential thermal analysis (DTA), scanning electron microscopy (SEM), electron probe X ray microanalysis (EPMA), secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM), to determine the effects of Bi2O3 mixed with silver and the efficacy of the resulting metal contacts in IC fabrications. It was observed that the additive,
In this paper results of new far-infrared and middle-infrared measurements (wavenumber range of 4000cm-1 - 100cm-1) in the range of the temperature from 300K to 8K of the CoFe2O4 ceramic are presented. The bands positions and their shapes are the same in the wide temperature range. The quality of the sample was investigated by X-ray, EDS and EPMA studies. The CoFe2O4 reveals the cubic structure (Fd-3m) in the temperature range from 85K to 360 K without any traces of distortion. On the current level of knowledge the polycrystalline CoFe2O4 does not exhibit phase transition in the temperature range from 8 K to 300 K.
The Y33.33Ni66.67-xAlx system has been investigated in the region 0 <= x <= 33.3. The alloys were synthesized by induction melting. Phase occurrence and structural properties were studied by X-Ray powder Diffraction (XRD). The Al solubility in each phase has been investigated by XRD and Electron Probe Micro-Analysis (EPMA). The hydrogenation properties were characterized by pressure-composition isotherm measurements and kinetic curves at 473 K. For x = 0, the binary Y33.33Ni66.67 alloy crystallizes in the cubic superstructure with F4-3m space group and ordered Y vacancies. For 1.67 <= x <= 8.33, the alloys contain mainly Y(Ni, Al)2 and Y(Ni, Al)3 pseudobinary phases; while for 16.67 <= x <= 33.33 they are mainly formed by ternary line compounds Y3Ni6Al2, Y2Ni2Al and YNiAl. Contrary to the binary Y33.33Ni66.67, Y(Ni, Al)2 pseudo-binary compounds crystalize in C15 phase (space group Fd-3m ) with disordered Y vacancies. The solubility limit of Al in the C15 YNi2-yAly phase is y = 0.11 (i.e., x = 3.67). The Y(Ni, Al)3 phase changes from rhombohedral (PuNi3-type, R-3m) to hexagonal (CeNi3-type, P63/mmc) structure for x increasing from 5.00 to 6.67. Upon hydrogenation,