Materials Literature
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We prepared silica glasses having various concentrations of chlorine, fluorine, hydrogen (SiO2−x), and oxygen (SiO2+x) to examine the precursors of paramagnetic centers induced by γ rays. In the case of glasses sintered under chlorine and hydrogen ambients, the concentration of the E′ center induced by γ-ray irradiati…
Calcium chloride framework alumino-silicate, (Ca 5.88 Mg 0.23 )(Al 4.26 Fe 0.46 )Si 2.00 O 15.68 Cl 2.64 , Al 5 Ca 6 Si 2 Cl 3 O 16 , (ideal), M r =793.9 (ideal), cubic, I43d, a=12.001 (2) A, V=1729 (1) A 3 , Z=4, D m =3.01, D x =3.056 Mg m -3 , λ(Mo kα 1 )=0.70930 A, μ=2.95 mm -1 , F(000)=1565, T=301 K, R=0.062 for 2…
The effect of MeV ion irradiation damage on the luminescence lifetime of erbium-doped silica glass films has been studied. The 10-μm-thick films were first implanted with 3.5 MeV Er at a fluence of 5×1015 cm−2. When optically pumped at 488 nm, the films show a clear photoluminescence spectrum centered around 1.535 μm,…
Melts of the eutectic alloy Ag-39.9 at. %Cu were cooled below the liquidus temperature by the glass flux method. The solidification behavior was followed by measuring the temperature change (recalescence), and the resulting microstructures were investigated by optical and electron microscopy. Up to a certain critical…
The organic crystal 4-nitro-4′-methylbenzylidene aniline (NMBA) was identified as a promising nonlinear material by the powder technique. The material gave a second harmonic intensity 16 times that of urea. Large single crystals of dimensions 5×3×1 cm3 were grown by the temperature lowering of a seeded supersaturated…
Abstract There is considerable interest in growing diamond layers and thin films for a wide range of applications. Some of these thin film requirements can be met already using existing diamond-like carbon coatings. This paper reviews the use of diamond-like carbon films in infra red optical, mechanical, electronic an…
The effect of rf power and substrate temperature Ts on the optical, electrical, and structural properties of a-Si1−xCx:H alloy films deposited in the new hot-plasma-box glow-discharge reactor are reported. The rate of deposition as well as the total fraction x of the carbon incorporated in the alloy films were found t…
Time-of-flight photocurrent measurements of 1,1-bis(di-4-tolylaminophenyl)cyclohexane doped bisphenol-A-polycarbonate show dispersive features at low temperatures. Within the nondispersive regime, transients show anomalously broad tails of universal shape. Their relative width is in quantitative accord with Monte Carl…
Abstract Three‐component emulsion polymer systems constitute an overall four‐component system from a morphological viewpoint. The aqueous phase is always the continuous phase within which 22 distinct and thermodynamically stable particle morphologies may exist. Six uniquely different categories of particles compose th…
Theoretical expressions are presented, at various levels of approximation, for the density of states <ρu(ω)≳ of harmonic modes with imaginary frequencies in liquids; these are also referred to as unstable modes. The relation between the frequency integral of <ρu(ω)≳, which is the fraction of unstable mod…
The magnetoresistance (MR) effects of La0.72Ca0.25MnOz (LCMO) magnetic films and LCMO/YBa2Cu3Oy (YBCO)/LCMO trilayered films were studied. The LCMO films have an MR ratio of −4% when applying 1 T at 77 K and this value is independent of the film thickness from 1500 to 4500 Å. In contrast to that, the MR ratio for LCMO…
Abstract Growth of diamond at conditions where it is the metastable phase can be achieved by various chemical vapour deposition methods. Atomic hydrogen plays a major role in mediating rates and in maintaining a proper surface for growth. Low molecular weight hydrocarbon species (e.g. CH3 and C2Hx are believed to be r…
We report on band-gap luminescence in strain-symmetrized, (Si${)}_{\mathit{m}}$/(Ge${)}_{\mathit{n}}$ superlattices grown on a step-graded, alloy buffer with a reduced dislocation density, using Sb as a surfactant. The luminescence efficiency for a (Si${)}_{9}$/(Ge${)}_{6}$ and (Si${)}_{6}$/(Ge${)}_{4}$ superlattice i…
The unique molecular conductors with p\ensuremath{\pi}-d mixing band structures (${\mathit{R}}_{1}$,${\mathit{R}}_{2\mathrm{\ensuremath{-}}}$N,N'-dicyanoquinonediimine${)}_{2}$Cu [(${\mathit{R}}_{1}$,${\mathit{R}}_{2\mathrm{\ensuremath{-}}}$DCNQI${)}_{2}$Cu] (${\mathit{R}}_{1}$,${\mathit{R}}_{2}$=${\mathrm{CH}}_{3}$,$…
Copper overlayers with thicknesses up to several tens of angstroms have been vapor deposited at various substrate temperatures onto rutile ${\mathrm{TiO}}_{2}$(110) surfaces that have different defect concentrations. The metal films have been studied by means of ${\mathrm{He}}^{+}$ low-energy ion scattering, x-ray pho…
Absorption spectra of Tm3+ ions in yttrium scandium aluminum garnet are reported between 1.9 and 0.25 μm at 4 K. Laser-excited fluorescence was observed at 4 K from Tm3+(4f12) multiplet manifolds 1D2, 1G4, 3F2, and 3H4 to the ground-state manifold 3H6. Emission from 1D2 and 1G4 also includes transitions to Stark level…
I-U characteristics measured in ${\mathrm{TlGaTe}}_{2}$ single crystals consist of two regimes: a linear one at low current densities and a nonlinear one at higher current densities. In the nonlinear part [negative-differential-resistance (NDR) region] of the curves, a considerable increase of the temperature of the s…
The critical behavior of pinned charge-density waves (CDW's) is studied as the threshold for sliding is approached. Using the Fukuyama-Lee-Rice Hamiltonian with relaxational dynamics, the polarization and linear response are calculated numerically. Analytic bounds on the subthreshold motion are used to develop fast nu…
The correlation between free-exciton and bound-exciton recombination has been investigated by cathodoluminescence in high-quality and impurity-controlled chemical-vapor-deposited (CVD) diamond films. The films are formed by [CO(5%)]/[${\mathrm{H}}_{2}$] using microwave-plasma CVD and are doped with ${\mathrm{B}}_{2}$$…
Using a measure of the asymmetry of the valence charge distribution in ${\mathit{A}}^{\mathit{N}}$${\mathit{B}}^{8\mathrm{\ensuremath{-}}\mathit{N}}$ compounds, a mapping to Phillips's ionicity scale is achieved.