Materials Literature
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A new route to the successful arc-discharge synthesis of pure boron nitride (BN) nanotubes is presented. The carbon-free plasma is established between ${\mathrm{HfB}}_{2}$ electrodes in a nitrogen atmosphere. This technique leads to the formation of BN nanotubes with very few layers including single- and double-layer…
Abstract Although there are no fundamental factors hindering the development of nanoscale structures, there is a growing realization that “engineering down” approaches, in other words a reduction in the size of structures generated by lithographic techniques below the present lower limit of roughly 1 μm, may become im…
A magnetic strip with rectangular cross section and infinite extension in the third, easy direction is used as a vehicle to explore numerical micromagnetic algorithms. The manifold of (meta-)stable domain wall solutions is calculated as a function of the thickness of the strip and of the relative strength of the magne…
Polycrystalline Cr2O3 films are prepared by normal pressure chemical vapour deposition (CVD), and electrical and optical properties of the films are investigated. The films are transparent from 800 to 1000 nm wavelength, and absorbing for wavelengths shorter than 800 nm. The optical band gap energy is Eopt = 2.98 to 3…
Copper oxide thin films were prepared by reactive rf magnetron sputtering of a pure copper target in an oxygen-argon atmosphere. The phases of the deposited films strongly depend on the oxygen content in the sputtering gas. X-ray diffraction studies show that by controlling the oxygen partial pressure single phase Cu2…
Changes in microstructure induced by heat treatments between 1000 and 1500 °C in Si3N4 based glasses and ceramics were characterized using x-ray diffraction and Raman scattering. The presence of free silicon appears to be a common feature of these families of materials. Si precipitates were observed by transmission el…
CdTe nanocrystals embedded in a sodium borosilicate matrix, obtained by a sol-gel process, present a wurtzite (hexagonal) structure. Low-temperature photoluminescence and absorption spectra are measured for samples containing bulklike nanocrystals large enough to suppress confinement effects. Thus, the fundamental fre…
A non-separation approach to determine the spark-processed porous silicon thermal parameters is presented. This thermal characterization was performed through application of the photoacoustic technique, in combination with compositional models for spark-processed porous silicon samples. The thermal parameters obtained…
The spatial distributions of the secondary-electron emission sites and energies at these emission sites in Si have been simulated by a Monte Carlo method. These spatial distributions are found to be nonuniform and can be described by multifractal analysis, which is performed with a box-counting method. The results of…
A generalization of the kinetic lattice gas model is used to study the coverage and temperature dependence of the sticking coefficient due to intrinsic and extrinsic precursors and in the presence of lateral interactions.
An angle-resolved photoemission (PE) study is performed on graphite intercalation compounds (GIC's) with Eu and Yb prepared in situ by deposition of the pure metals onto single-crystalline graphite(0001) surfaces and subsequent annealing. The low-energy-electron-diffraction patterns reveal a sharp (\ensuremath{\surd}3…
The room-temperature electrical conductivity of tensile-drawn and oriented poly(p-phenylenevinylene), PPV, doped with sulfuric acid (${\mathrm{H}}_{2}$${\mathrm{SO}}_{4}$) is approximately ${10}^{4}$ S/cm for current along the draw direction; the anisotropy ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{\ensuremath{\paralle…
A large negative magnetoresistance (MR) sharply peaked at the first-order Verwey transition temperature ${T}_{V}=119.79\ifmmode\pm\else\textpm\fi{}0.02$ K has been measured in a synthetic single crystal of magnetite ${\mathrm{Fe}}_{3(1\ensuremath{-}\ensuremath{\delta})}{\mathrm{O}}_{4}$, $\ensuremath{\delta}=0.0006$.…
The inter-\ensuremath{\pi}-band response function of a single-layer carbon nanotube is calculated within the random-phase approximation. Such a cylindrical system exhibits rich inter-\ensuremath{\pi}-band excitations. The decoupled \ensuremath{\pi} plasmons of different angular momenta (L's) strongly depend on the tra…
The structure of the disodium salt of the [Eu(C22H26N3O11)(H2O)]2− complex anion is isomorphous with that of the corresponding gadolinium(III) compound. The EuIII atom is nine-coordinate with the donor atoms disposed at the vertices of a tricapped trigonal prism, the cap positions being occupied by two N atoms of the…
X-ray photoemission spectra (XPS) of NaF, MgO, ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$, ${\mathrm{SiO}}_{2}$, InP, and ${\mathrm{NaH}}_{2}$${\mathrm{PO}}_{4}$ collected using synchrotron radiation in the 1900--3400-eV energy range are reported. Accurate XPS spectra have been collected around the Na, Mg, Al, Si, and P 1s…
Using x-ray photoelectron spectroscopy (XPS), W 4f core level spectra of electrochromic HxWO3 films have been investigated as a function of the injected charge. W 4f peaks become broader with increasing injected charge. The line shape analysis of W 4f XPS spectra of amorphous HxWO3 films reveals that each spin-orbit s…
We have studied the orientational order in a liquid crystalline mixture consisting of benzene and 4-n-pentyl-4′-cyanobiphenyl (5CB) employing molecular dynamics simulation and NMR spectroscopy. The temperature-dependent order parameters obtained from the NMR experiments were used to determine the average benzene–5CB a…
The underlying ambition of this work in addition to the x-ray diffraction electronic density determination is the estimation of the nonlinear optical properties of NPP [N-(4-nitrophenyl)-(L)-prolinol] from a model due to Robinson allowing us to connect the polarizabilities, under some approximations, to the different…
Indium oxide (InOx) films with a thickness of 100–500 nm were prepared by dc magnetron sputtering onto Corning 7059 glass substrates. The as-deposited films were microcrystalline as revealed by x-ray diffraction analysis. The conductivity of the as-deposited films was of the order of 10−3–10−2 Ω−1 cm−1 and increased u…