Materials Literature
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The growth and magnetic properties of epitaxial magnetite ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ on GaAs(100) have been studied by reflection high-energy electron diffraction, x-ray photoelectron spectroscopy, magneto-optical Kerr effect, and x-ray magnetic circular dichroism. The epitaxial ${\mathrm{Fe}}_{3}{\mathrm{O}}…
Three different film systems have been systematically investigated to understand the effects of strain and substrate constraint on the phase transitions of perovskite films. In $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ films, the phase transition temperature ${T}_{c}$ was determined by monitoring the superlattice peaks…
We have recently reported the growth of freestanding, single-crystal, seamless nanorings of zinc oxide via a spontaneous self-coiling process during the growth of polar-nanobelts [X.Y. Kong et al., Science 303, 1348 (2004)]. The nanoring is made by coaxial and uniradius loop-by-loop winding of a fine ZnO nanobelt. An…
High-permittivity dielectric NiO-based ceramics co-doped with Li and Al (LANO) have been prepared by a traditional solid-state synthesis. Analyses of the ceramic microstructure and composition indicate that Al ions are distributed in grain boundaries, and that uniform boundaries indexed as NiAl2O4 surround the grains.…
The concentration distribution and electronic structure of N atoms doped in multiwalled banboo-like carbon nanotubes (CNTs) are examined by photon energy-dependent x-ray photoelectron spectroscopy and x-ray absorption near edge structure. The inner part of the nanotube wall has a higher N concentration and contains mo…
We report on field emission from SnO2 nanobelt arrays with the length of about 90 μm grown on silicon substrates. The turn-on field of the nanobelt arrays at the current density of 1μA∕cm2, is 4.5, 3.0, 2.4, and 2.3V∕μm as the distance between anode and cathode (d) is 0.1, 0.2, 0.35, and 0.5 mm, respectively. The curr…
An L-glutamic acid based bolaamphiphile was observed to self-assemble into a novel "helical spherical-nanotube" with a molecular monolayered structure within a tubular wall.
An O–H stretching line at 3326.3cm−1 was previously assigned to a shallow donor that is introduced into ZnO by H. This infrared line has been found to appear in as-grown ZnO samples when they are annealed near 400 °C without an external source of H, showing that there is an H-containing defect in commercially availabl…
We assert that the physics underlying the extraordinary light transmission (reflection) in nanostructured materials can be understood from rather general principles based on the formal scattering theory developed in quantum mechanics. The Maxwell equations in passive (dispersive and absorptive) linear media are writte…
Abstract Nylon 12 (PA12) nanocomposites with different organoclay loadings were successfully prepared by melt compounding. X‐ray diffraction indicated the dominance of the exfoliated clay morphology throughout the matrix after mixing in a Brabender twin‐screw extruder, in accordance with transmission electron microsco…
Good things come in small packages: For its moderate molecular weight, the metallostar complex [Fe{Gd2L(H2O)4}3]4− (see picture; L is a bipyridine–poly(aminocarboxylate) derivative) displays exceptionally high proton relaxivity, which is explained in terms of a rigid supramolecular structure, two inner-sphere water mo…
The existence of image states in small clusters is shown, using a quantum-mechanical many-body approach. We present image state energies and wave functions for spherical jellium clusters up to 186 atoms, calculated in the GW approximation, where G is the Green's function, and W the dynamically screened Coulomb interac…
The field-dependent ion transport in thin samples of different glasses is characterised by means of nonlinear conductivity spectroscopy. AC electric fields with strengths up to 77 kV/cm are applied to the samples, and the Fourier components of the current spectra are analysed. In the dc conductivity regime and in the…
V(I) characteristics have been performed in a monocrystalline microbridge of $Bi[Pb]-2212$. The vortex phase diagram has been greatly investigated. Linear but non-ohmic Voltage(Current) (V(I)) curves with well defined critical current have been observed. A departure from this behavior is observed near the peak effect…
We simulate cellular and dendritic growth in directional solidification in dilute binary alloys using a phase-field model solved with adaptive-mesh refinement. The spacing of primary branches is examined for a wide range of thermal gradients and alloy compositions and is found to undergo a maximum as a function of pul…
We present the first resonant x-ray reflectivity measurements from a liquid surface. The surface structure of the liquid Hg-Au alloy system just beyond the solubility limit of 0.14at% Au in Hg had previously been shown to exhibit a unique surface phase characterized by a low-density surface region with a complicated t…
Hydrogen-doped zinc oxide (ZnO:H) films were deposited by rf magnetron sputtering as transparent conductive films. The resistivity of ZnO:H film was significantly reduced by the addition of H2 in Ar during rf sputtering. The electrical resistivity of ZnO:H films reached 2×10−4Ωcm. The carrier concentration increased w…
Abstract Poly(ε‐caprolactone)/montmorillonite nanocomposites were prepared maintaining a constant inorganic content with three means: melt blending of poly(ε‐caprolactone) with natural or organomodified clays, in situ polymerization of ε‐caprolactone in the presence of organomodified clays, and initiation of ε‐caprola…
In this letter we demonstrate that with a different principle, BaTiO3 ceramics, so far considered as inferior piezoelectrics compared with Pb(Zr,Ti)O3 (PZT), can show a large recoverable electrostrain. This principle utilizes a point-defect-mediated reversible domain switching mechanism, which can in theory generate 0…
Using the extended tight-binding model that allows bond lengths and angles to vary, the optical transition energies Eii in single-wall carbon nanotubes are calculated as a function of inverse tube diameter. After geometrical structure optimization, the 2n+m=constant family behavior observed in photoluminescence (PL) e…