Materials Literature
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Thin TiO2 films with rutile short-range atomic order grown at room temperature have a nanostructure of rectangular domains based on a faulted rutile structure. Raman scattering by nanomosaic rutile in single layer TiO2 and TiO2–Al2O3 nanolaminate films is reported here. In all architectures, the Eg phonon mode frequen…
Sputter-deposited Ba0.5Sr0.5TiO3 films on (001) MgO were characterized for their dielectric properties with different lattice structures. With varying Ar:O2 ratios during deposition, the films showed either in-plane (c<a) or out-of-plane (c>a) tetragonal distortions, significantly affecting the dielectri…
Zn O ∕ Mg 0.1 Zn 0.9 O multiquantum-well (MQW) structures were grown on ZnO substrates by molecular beam epitaxy. Abrupt interfaces and well/barrier width in the MQWs were confirmed by x-ray diffraction measurement and transmission electron microscopy. The transition energy of the localized exciton in the ZnO∕Mg0.1Zn0…
Magnetoresistance (MR) of a nanostructured material, monodisperse Fe3O4 nanospheres of about 200nm coated with thin SiO2 and compactly cold pressed and sintered, has been investigated. A high MR, up to 10.8% at 1T and 17% at 8T, has been observed at 100K. This enhanced MR is likely arising from the spin-polarized tunn…
Zinc oxide (ZnO) crystal is a semiconductor material; the direct measurement and the interpretation of its piezoelectric coefficients are challenging. In this letter, the authors investigate the piezoelectric properties (d33 coefficient) of a bulk ZnO sample by measuring its converse piezoelectric effect using an opti…
We have studied the nucleation kinetics of charged colloidal model systems under salt free conditions crystallizing in bcc structure covering a wide range of particle number densities $18\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}{\mathrm{m}}^{\ensuremath{-}3}\ensuremath{\le}n\ensuremath{\le}66.3\phantom{\rul…
Symmetric BiFeO3∕SrTiO3 superlattices were fabricated by pulsed laser deposition on SrTiO3 (100) substrates. Frequency independent and near saturated P-E hysteresis was observed in the case of a superlattice (periodicity of ∼11nm) as compared to leaky hysteresis observed in epitaxial BiFeO3. Room temperature leakage c…
A quaternary glass system, TeO2–ZnO–Nb2O5–MoO3, with higher linear and nonlinear indices, third order optical susceptibility (χ3), and Raman gain coefficient and gain bandwidth is reported. The χ3 of these glasses are ∼80 times higher than the silica glass and 1.6 times higher than pure TeO2 glass; Raman gain coeffici…
Pull-back and shaking table test results on a simple model of a three-storey structure that includes shape memory alloys (SMA) copper-based dampers are presented and discussed. The model corresponds to a rigid-framed steel structure and the dampers to austenite CuAlBe wires inserted as bracing at each story. The inclu…
The authors report on the calculation, by density functional theory, of the total energy and of the magnetic properties of wurtzite ZnO doped with diluted Fe impurities in the presence of vacancies. They found that the complex FeZn–VZn—where the Zn vacancy (VZn) occupies the next nearest neighbor position to Fe atom—i…
Computer simulations of a polymer chain of length N strongly adsorbed at the solid-liquid interface in the presence of explicit solvent are used to delineate the factors affecting the N dependence of the polymer lateral diffusion coefficient, D(||). We find that surface roughness has a large influence, and D(||) scale…
The transient currents induced by an applied direct voltage (dc) electric field have been measured liquid-crystal cells in nematic phase. The experimental results show that the addition of insulating nanoparticles, such as diamond powders, leads to a reduction of the ion concentration in cells so as to drastically red…
Photon recycling in strain-balanced quantum well solar cells grown on distributed Bragg reflectors has been observed as a suppression of the dark current and a change in electroluminescence spectra. Comparing devices grown with and without distributed Bragg reflectors we have demonstrated up to a 33% reduction in the…
Formation of condensed films of nanoparticles having small ratio of metal-core-diameter to organic-shell-thickness is desired for several applications in nanotechnology. We report here results of a X-ray scattering study carried out to understand structure and morphology of monolayer of such nanoparticles having gold-…
Extended x-ray absorption fine structure (EXAFS) has been measured from liquid helium to ambient temperature at the $\mathrm{Cu}\phantom{\rule{0.2em}{0ex}}K$ edge of copper chloride (CuCl) to investigate the local origin of negative thermal expansion. A quantitative analysis of the first coordination shell, performed…
The authors report structural, magnetic, and electrical properties of parasitic phase-free, well-ordered epitaxial La2CoMnO6 films. Despite their single ferromagnetic transition around 240K, they demonstrate that they possess a bidomain structure with distinct magnetic characteristics. The B-site ordering in the films…
By employing polarization- and temperature-dependent near-edge x-ray-absorption fine structure (NEXAFS) studies, we show that vertically aligned carbon nanotubes when subjected to low-pressure radio-frequency (rf) glow discharge can easily be doped with nitrogen atoms at predominantly graphitelike substitutional sites…
The authors have observed highly circularly polarized electroluminescence from organic light-emitting diodes (OLEDs) using wide-band reflector consisting of three-layered left-handed polymeric cholesteric liquid crystal (PCLC) films. By simply attaching the wide-band reflective PCLC reflector to a conventional OLED, t…
Negative thermal expansion (NTE) is known in ${\mathrm{Cu}}_{2}\mathrm{O}$ below $300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and in ${\mathrm{Ag}}_{2}\mathrm{O}$ up to its decomposition temperature of about $500\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Inelastic neutron scattering measurements in ${\mathrm{Cu}}_{2}\mathr…
In gold nanoparticles (Au NPs) capped with dodecanethiol (DT), the authors report the observation of superparamagnetic blocking temperature TB≃50K in D≃5nm NPs but only diamagnetism in 12nm NPs. For T<TB=50K, the strong temperature dependence of coercivity Hc, saturation magnetization Ms, and exchange bias He (…