Materials Literature
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Element specific magnetization has been determined at the surface and in the bulk of Co2Cr0.6Fe0.4Al Heusler alloy films grown on α-Al2O3 and capped by Al, using x-ray magnetic circular dichroism both in transmission and total electron yield. The magnetic moments for Co and Fe are considerably reduced at the upper sur…
We suggest double-resonant (binary) metamaterials composed of two types of magnetic resonant elements, and demonstrate that in the nonlinear regime such metamaterials provide unique possibilities for phase-matched parametric interaction and enhanced second-harmonic generation.
Charging mechanisms of trapped, element-selectively excited free SiO2 nanoparticles by soft x rays are reported. The absolute charge state of the particles is measured and the electron emission probability is derived. Changes in electron emission processes as a function of photon energy and particle charge are obtaine…
An equilibrium phase diagram satisfying the Gibbs phase rule is computed for the PbZrO3-PbTiO3 (PZT) system from a low-order Landau expansion in the approximation of the theory of regular solutions. We show that in the equilibrium phase diagram, miscibility gaps replace the morphotropic phase boundary and the paraelec…
Metal-ferroelectric-insulator-semiconductor capacitors with Pb(Zr0.53,Ti0.47)O3 (PZT) ferroelectric layer and dysprosium oxide (Dy2O3) insulator layer were fabricated and characterized. The measured memory window of 0.86V was close to the theoretical value ΔW≈2dfEc≈0.78V at a sweep voltage of 8V. The size of the memor…
We present optically pumped emission data for ZnO, showing that high excitation effects and stimulated emission/lasing are observed in nanocrystalline ZnO thin films at room temperature, although such effects are not seen in bulk material of better optical quality. A simple model of exciton density profiles is develop…
This study examined the effects of permanent residual compressive stress on the ferroelectric properties of PbZrxTi1−xO3 (PZT) films that was induced during cooling after annealing. PZT films were deposited on the tensile side of elastically bent silicon substrates by rf magnetron sputtering using a single oxide targe…
Polymerizable nematic liquid crystal (LC) was adopted as a resist for our newly developed nanoimprinting lithography process. Liquid crystal molecules were self-aligned during imprinting process without precoated alignment layer. The large patterned area was able to achieve 4×4cm2 at very low impriting pressure, 1.5ba…
We report the synthesis of Si nanocrystals embedded in a SiO2 matrix using reactive laser ablation in oxygen atmosphere followed by annealing. We observe a strong photoluminescence signal, which is related to the oxygen background pressure used for synthesis. The average nanoparticle size, obtained independently by fi…
As a representative example, nano-LiNbO3 is prepared by a wet-chemical method in order to enhance its photocatalytic activity through improving the surface area. The samples perform good crystallinity from powder x-ray diffraction and transmission-electron-microscope observations. It is surprising that photocatalytic…
Boning up on patterning: Patterned calcium carbonate films with dimensions of 200–400 μm were obtained using the photolithographic properties of a polysilane-based ABA block copolymer, PHEMA-PMPS-PHEMA. These patterns may serve as a 2D model system for CaCO3 biomaterials in which both the CaCO3 resorption by osteoclas…
Abstract Fuel processing systems that are used in conjunction with polymer electrolyte membrane (PEM) fuel cells require high activity water gas shift (WGS) catalysts that remove carbon monoxide, a poison for membranes in the fuel cell stacks. WGS activity of various noble metals supported on cubic, nanocrystalline, h…
We report here the study by optical microspectroscopy of crystalline ZnO nanoparticles produced by room-temperature organometallic synthesis. We present resonant Raman scattering spectrum obtained from different sized nanostructures from which the longitudinal-optical (LO) phonon frequency has been found to be very we…
The kinetic model of stepwise polymerization is revisited, with some adaptations for its application to the kinetics of oriented attachment of nanoparticles in colloidal suspensions, which results in the formation of anisotropic particles. A comparison with experimental data reported in the literature shows good agree…
It is well known that nitrogen forms aggregates in diamond. However, little is known regarding aggregation of boron, an impurity that can be incorporated in very high concentrations. In this paper we present the results of first-principles calculations regarding the structure and properties of boron-aggregates, and si…
Empirical tight-binding simulations of the band structure of $1T\text{\ensuremath{-}}{\mathrm{TaS}}_{2}$ reveal that the combination of spin-orbit coupling and the low-temperature $\sqrt{13}\ifmmode\times\else\texttimes\fi{}\sqrt{13}$ reconstruction generates a distinct and very narrow band at the Fermi level. Spin-or…
We developed transparent 3.5mol% Ho3+-doped oxyfluoride nano-glass-ceramics, where the Ho3+-dopants dissolve in the 6nm diameter β-PbF2 nanocrystals. The cubic site of Ho3+ and a low vibration frequency of its PbF2 environment result in an intense and 50nm broad emission band I65→I85 of Ho3+ at 1.2μm with a temperatur…
Kinetics of oxidation of MgO–C refractory bricks containing 14.3% graphite, 80.9% magnesia, and 4.8% phenolic resin is investigated comprehensively. Effect of temperature and grain size distribution on the rate of oxidation of graphite is evaluated by application of a mathematical model developed on the basis of shrin…
The correlation-driven metal-insulator transition (MIT) of BaVS$_3$ was studied by polarized infrared spectroscopy. In the metallic state two types of electrons coexist at the Fermi energy: The quasi 1D metallic transport of $A_{1g}$ electrons is superimposed on the isotropic hopping conduction of localized $E_g$ elec…
Using neutron elastic and inelastic scattering and high-energy x-ray diffraction, we present a comparison of $40%\phantom{\rule{0.3em}{0ex}}\mathrm{Pb}({\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}\text{\ensuremath{-}}60%\phantom{\rule{0.3em}{0ex}}{\mathrm{PbTiO}}_{3}$ (PMN-60PT) with pure $\mathrm{Pb}({\mat…