Materials Literature
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The localization of electrons at ${\mathrm{W}}^{6+}$ sites perturbed by lanthanum in ${\mathrm{PbWO}}_{4}$ is studied by electron spin resonance (ESR) and thermally stimulated luminescence (TSL) measurements. The $({\mathrm{WO}}_{4}{)}^{3\ensuremath{-}}\ensuremath{-}{\mathrm{La}}^{3+}$ centers are created at the ${\ma…
Whereas boron nitride nanotubes have elastic properties similar to those of their carbon counterparts, they can have a very different response to plastic deformation. $(n,n)$ boron nitride nanotubes have comparable plastic limits to those of carbon tubes with similar wrapping angle. $(n,0)$ boron nitride nanotubes, ho…
Measurements of initial adsorption probabilities, S0, as well as the coverage dependence of the adsorption probability, S(ΘCO), of CO on Zn–ZnO [ZnO(0001)] and O–ZnO [ZnO(0001̄)] are presented. The samples have been characterized by He atom scattering, He atom reflectivity measurements, LEED, and XPS. Samples with dif…
Aligned carbon nanotubes were synthesized on Ni-coated Si substrates using microwave plasma-enhanced chemical vapor deposition. The surface morphology of Ni thin films was varied with the rf power density during the rf magnetron sputtering process. It was found that the growth of carbon nanotubes was strongly influenc…
The crystal structures of samarium nitrate Sm(NO 3 ) 3 6H 2 O at temperatures 297, 253 and 193 K±1 K were investigated by single crystal X ray diffraction technique. The crystal symmetry at the temperatures was triclinic with space group P \bar1. The structures were solved by using Fourier techniques. The full matrix…
The photoluminescence properties and quantum efficiency of potential red, green, and blue (RGB) phosphors are measured under near-ultraviolet excitation (380–420 nm). The suitability of several phosphors is discussed for their application in phosphor-liquid crystal displays (LCDs). K5Eu2.5(WO4)6.25, SrGa2S4:Eu, and Ba…
The effect of nonstoichiometry (δ) on the magnetic properties of (Mg0.22Mn0.07Fe0.71)3−δO4 ferrite was investigated. The nonstoichiometry was controlled via a solid state electrochemical method to encompass from δ=+0.005 to −0.006. Initial permeability was found to be affected significantly by nonstoichiometry. From t…
We investigate, through first-principles calculations, the energetics of substitutional carbon and oxygen impurities as well as complexes involving these impurities and vacancies in cubic boron nitride $(c\ensuremath{-}\mathrm{BN}).$ The formation energies and the electronic and structural properties of these defects…
Dynamic electrical analysis shows that at high temperatures (above the glass transition temperature), the electrical properties of polyetherimide are strongly influenced by space charge. In this article we have studied the relaxation of space charge in two commercial varieties of polyetherimide: Ultem 1000 and Ultem 5…
The magnetic properties and structure evolution of CoxC1−x (x=44, 65, 71 at. %) nanocomposite films prepared by pulsed filtered vacuum arc deposition were studied. The as-deposited films consist of amorphous Co clusters in a-C and are soft ferromagnets. The low coercivity in the amorphous films is due to the very low…
We have studied the multiphonon resonant Raman scattering from confined and interface polar optical phonons in spherical nanocrystallites. The intermediate virtual states in the scattering process are taken into account as Wannier-Mott confined excitons in a spherical dot. Fr\"ohlich interaction between excitons and o…
We report synthesis and examination of the electronic properties of an isomorphous series of mixed-stack organic charge-transfer complexes, composed of [bis(ethylenedithio)tetrathiafulvalene] (BEDT-TTF)-based electron donors and electron acceptors of halogen-substituted tetracyanoquinodimethanes (TCNQ's). Single cryst…
The valence-band structure of ${\mathrm{CoAs}}_{3},$ ${\mathrm{CoSb}}_{3},$ and ${\mathrm{RhSb}}_{3}$ with a skutterudite-type crystal structure has been investigated by x-ray photoelectron spectroscopy. The photoemission spectra are compared with recent density-of-states calculations. Our photoemission spectra result…
We propose an optical configuration of a nontwist quarter-wave liquid-crystal cell for a high-contrast reflective display that can be applied to most nontwist display modes. By fabricating a homogeneous cell with the proposed configuration, we have demonstrated a high contrast ratio of 50:1 without using a wideband re…
First-principles calculations are employed to study ${\mathrm{SrTiO}}_{3}(001)$ $(1\ifmmode\times\else\texttimes\fi{}1)$ surfaces with both SrO and ${\mathrm{TiO}}_{2}$ termination. A detailed geometry of the relaxed systems, surface energy, and the individual relaxation energies of the two types of surface are obtain…
The bandwidth-controlled metal-insulator (MI) transition in pyrite-type NiS 2- x Se x has been investigated. The results indicate that the approach to the MI transition from the metallic side is profoundly affected by the presence of the antiferromagnetic metal (AFM) phase (0.4< x <1.0) immediately next to the MI phas…
A theoretical investigation of the dynamics of photopolymerization-induced phase separation (PIPS) and morphology development in a nematic liquid crystal (LC) polymer network mixture has been undertaken by incorporating photopolymerization kinetics into the coupled time-dependent Ginzburg-Landau (TDGL–Model C) equatio…
Lanthanum cobalt oxide LaCoO3 has a rhombohedrally distorted perovskite structure with the crystal space group of R3c.1-3) Raccah and Goodenough have reported that the crystal space group varies with increasing temperature from R3c to R3 around K. In the high temperature phase, two kinds of inequivalent Co atoms order…
Glasses with a composition xLi2O⋅(1−x)B2O3 were investigated by low-frequency Raman scattering in the composition range x=0–0.28. The evolution of the quasielastic line, the boson peak, the Debye frequency, and some other glass parameters with the composition was analyzed. The frequency of the boson peak ωb shifts wit…
The series of compounds ${\mathrm{Fe}}_{x}{\mathrm{Cr}}_{3\ensuremath{-}x}{\mathrm{Se}}_{4},$ with $0<~x<~3,$ has been prepared and various thermoelectric properties measured from 5 to 900 K. Unlike most thermoelectric materials that are band semiconductors with high carrier mobilities, ${\mathrm{Fe}}_{x}{\mathr…