Search results for "Electron microscope"
showing 10 items of 784 documents
Characterization of Dielectric Anomaly in Solid Solution Based on BaTiO3
2011
The influence of Zr doping on a structure and dielectric properties of Ba0.8Sr0.2TiO3 were studied. For this purpose Ba0.8Sr0.2Ti0.75Zr0.25O3 ceramics were obtained by a conventional method and were determined by an X-ray diffraction (XRD) and scanning electron microscopy (SEM) for crystallographic, surface morphological and compositional studies. The temperature and frequency dependence of dielectric permittivity were studied in the temperature range from 150 to 500 K and the frequency between 20 Hz and 1000000 Hz. The thermal behavior of the Ba0.8Sr0.2Ti0.75Zr0.25O3 ceramics were also studied using Differential Scanning Calorimetry. A diffusivity coefficient γ was calculated.
X-ray diffraction line-broadening study on two vibrating, dry-milling procedures in kaolinites
2009
Due to the great technological importance of the microstructure of kaolinite, characterizing its evolution during dry milling of kaolin and analyzing the microstructural information obtained from different methods were the main aims of this work. The microstructural alteration of kaolinite is evaluated by X-ray diffraction and electron microscopy methods, comparing the results obtained and analyzing the correlations between them. The Warren-Averbach and Voigt-function methods of X-ray diffraction microstructural analysis have been applied successfully to the study of the effects of two different, vibrating-cup dry-milling configurations in the microstructure of kaolinite from the reflection…
Gas sensing properties of Zn-doped p-type nickel ferrite
2012
Abstract The influence of zinc ion to the NiFe2O4 p-type semiconductor gas response characteristics is demonstrated. For characterization of gas sensor material, synthesized by sol–gel auto combustion method, X-ray diffraction (XRD), scanning electron microscopy (SEM), DC resistance and impedance spectroscopy (IS) measurements were employed. The response change of Zn doped nickel ferrite is related to the interruption of hole hopping between nickel ions. This was improved by change of conductivity type with temperature and gas exposure.
Preparation and Electric Properties of Barium Zirconium Titanate Ceramic
2015
The relaxor behavior of barium zirconium titanate ceramics BaZr0.35Ti0.65O3 prepared by a conventional sintering process was investigated. The synthesized material was determined by an X-ray diffraction and scanning electron microscopy. Based on performed studies, the BaZr0.35Ti0.65O3 ceramic material has been identified as canonical relaxor, related to the Ti-rich polar regions. The freezing temperature Tf and activation energy Ea are calculated from the Vogel-Fulcher relationship.
CuInS2 Films for Photovoltaic Applications Deposited by a Low-Cost Method.
2006
We report an atmospheric-pressure deposition method for preparing well-adhered and compact CuInS 2 films. The precursor film is obtained by a solution-coating technique and is subjected to a low-cost and safe one-step reduction-sulfurization treatment. A maximum thickness of 300 nm is achieved per layer, and up to three layers were sulfurized at a time. The obtained films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and visible-near-infrared (vis-NIR) spectrophotometry.
Structural investigation of four-centre photopolymerisation of bis-phthalamic bis-chalcone derivative in the crystalline state
1997
By combining the results obtained from an electron diffraction tilting series with solid state NMR and powder X-ray diffraction, it was possible to determine the unit cell parameters and space group of BPABC crystals grown from DMAA solution both before and after irradiation. Subsequently semi-empirical quantum mechanical and packing energy calculations led to a model structure which agreed well with all the electron diffraction data and thus provided insight into the cross-linking mechanism. © 1997 John Wiley & Sons Ltd.
Template-based synthesis of nickel oxide
2015
Nanocrystalline NiO has been produced using a facile template-based synthesis from nickel nitrate solutions using cellulose as a template. Thus obtained oxides were studied by scanning electron microscopy, x-ray diffraction, Raman scattering spectroscopy, photoluminescence spectroscopy and confocal spectromicroscopy. The filamentary/coral morphology of the samples has been evidenced and is built up of agglomerated nanocrystallites with a size in the range of about 26-36 nm. The presence of two-magnon contribution in Raman scattering spectra suggests the existence of antiferromagnetic ordering at room temperature. Finally, the observed near-infrared photoluminescence band at 850 nm has been …
Effect of gamma radiation on thermostimulated exoelectron emission from Gd2O3 films
2020
Abstract The effect of gamma irradiation on Gd2O3 films was studied using the thermostimulated exoelectron emission (TSEE) technique. The films were deposited on a glass and Si/SiO2 substrates using an extraction-pyrolytic method. Crystalline structure, chemical composition, film thickness and surface morphology were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films were irradiated by 10 MeV gamma photons and TSEE was measured from the irradiated films. It was found that gamma irradiation decreases TSEE intensity and the area below TSEE spectral curves. A linear correlati…
The Effects of 3d Admixtures on Properties of Relaxor PLZT8/65/35 Ceramics
2012
A study of the effects of the 3d dopants Mn, Fe, Co, Ni, and Cu on relaxor behavior and other properties of the ferroelectric PLZT8/65/35(La8) ceramic compound by X-ray diffraction, electron microscopy and other techniques is reported. The complex dielectric permittivity ϵ* = ϵ′-iϵ′′ is measured in the 20–400°C range of temperature at frequencies within the range of 102 – 106 Hz. Essential changes caused by the admixtures in the behavior of dielectric permittivity with frequency and temperature are observed along with changes in the XRD SEM patterns are observed. The mechanisms of the phenomena are discussed.
Vapor growth of Hg1−xCdxI2 on glass using CdTe buffer
2001
Abstract Vapor phase epitaxy (VPE) of Hg1−xCdxI2 layers on glass substrates covered by a CdTe buffer layer has been studied. The buffer layers of 2–4 μm thickness were formed by VPE using polycrystalline CdTe and Cd metal sources. The Hg1−xCdxI2 layers were grown using a (Hg1−yCdy)1−z(I2)z polycrystalline source, with a composition in the range of y=0.1–0.5 and z=0.5–0.8. Scanning electron microscopy and X-ray diffraction studies have shown that the composition and structure of Hg1−xCdxI2 layers depend strongly on the VPE conditions. Varying the growth time and source composition, it has been possible to obtain Hg1−xCdxI2 layers with the composition x in the range from approximately 0 (HgI2…