Materials Literature
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We discuss effects of the different chemical bondings on the island morphology and on the island density scaling in two-component submonolayer growth. Different regimes depending on the strength of the mutual interactions and on the relative mobility of species are described and studied by kinetic Monte Carlo simulati…
In a recent Letter, Berciu and Bhatt have presented a mean-field theory of ferromagnetism in III-V semiconductors doped with manganese, starting from an impurity band model. We show that this approach gives an unphysically broad impurity band and is thus not appropriate for (Ga,Mn)As containing 1-5% Mn. We also point…
We synthesized a series of CoFe Prussian blue analogues along which we tuned the amount of cesium cations inserted in the tetrahedral sites of the structure. Structure and electronic structure have been investigated, combining XANES, infrared spectroscopy, powder X-ray diffraction experiments, and magnetization measur…
Periodic mesoporous silicas (PMSs) give enormous stimulus to the field of nanostructured organic−inorganic composite materials, opening new horizons for selective organic transformations and material science. This article outlines advanced synthetic concepts of their intraporous surface organometallic chemistry involv…
A highly efficient, visible wavelength (λ MAX = 700 to 800 nm) fluorescence is reported for four water-soluble monolayer-protected gold clusters (MPCs). For 451 nm excitation, the quantum yield of the luminescence of MPCs with 1.8 nm diameter cores and protected by monolayers of tiopronin thiolate is estimated as 0.00…
Testing of two different samples of Cu/silicalite-1 with CO reveals the existence of Cu+ sites typical of oxide-supported copper. CO adsorbed on these sites is characterized by a band at 2137 cm−1. Heating the samples in a CO atmosphere leads to reduction of particular Cu2+ cations and the Cu+ sites formed behave as C…
This study investigates the dynamics of an acoustically driven air bubble in water. Depending on the values of external parameters, the radial oscillations of the bubble can be either stable or chaotic. The necessary condition of chaotic behaviour is identified to be the non-zero amplitude of the bubble's afterbounces…
Lacunary polyoxometalates, large inorganic, structure-design-flexible, nanocluster crystals are found to have higher optical nonlinearity than KH2PO4 by the powder second-harmonic-generation method. Moreover, the capability of generating ultraviolet radiation down to around 300 nm is found. The basic criteria to desig…
In2S3 nanoparticles, short nanowhiskers, nanorods and finger-structure nanocrystals with stoichimetric composition and high quality can be prepared by a solvent-reduction route. It was found that the reagent concentrations, solvent and reaction temperature played important roles in the shape control. We also successfu…
Low-energy spin excitations play an essential role in determining the characteristics of the phase transitions in the colossal magnetoresistant manganese-oxides (manganites). Inelastic neutron scattering has been utilized to study the spin excitations of the ferromagnetic (FM) ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm…
BaPbO 3 (BPO) films were prepared by rf-magnetron sputtering at temperatures as low as 350 °C. These films possessed low electrical resistivity of 1.4×10−3 Ω cm, which is appropriate for electrodes. The BPO electrode has an advantage over a Pt electrode in that it lowers the crystallization temperature of Pb(Zr0.53Ti0…
We have developed a concurrent x-ray diffractometer that concurrently measures spatially resolved x-ray diffraction (XRD) spectra of epitaxial thin films integrated on a substrate. A convergent x-ray is focused into stripe on a substrate and the diffracted beam is detected with a two-dimensional x-ray detector. The ob…
The role played by the Nd ions in the magnetic properties of ${\mathrm{Nd}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3}$ and ${\mathrm{Nd}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ is studied using static magnetization, neutron diffraction, and high frequency (9.4--475 GHz) electron spin resonance (ESR). We show tha…
In this letter, the abnormal temperature dependence of low-field magnetization of FeCr2−xAlxS4 (0⩽x⩽0.7) is reported. In addition to a large irreversibility between zero-field-cooling (ZFC) and field-cooling (FC) magnetization for all samples, a cusp is also observed in both FC and ZFC curves for x⩽0.2. The cusp and t…
We report on the optical properties of undoped single crystal ${\mathrm{LaMnO}}_{3},$ the parent compound of the colossal magnetoresistive manganites. Near-normal-incidence-reflectance measurements are reported in the frequency range of $20\ensuremath{-}50000 {\mathrm{cm}}^{\ensuremath{-}1}$ and in the temperature ran…
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Reversible generation and dissolution of 3 nm silver particles in a glass containing only silver ions are repeatedly achieved through a combination of x-ray radiation and heat treatment. X-ray irradiation and 400 °C heat treatment induce a yellow color, whereas heating at 500 °C can change the glass to colorless again…
A rough and thick film of doped praseodymium nickel oxide (Pr2NiO4+δ) has been obtained by combining the spray pyrolysis deposition technique with rapid thermal annealing process. The precursors are nitrate solutions. Spectral emissivity measurements from the far infrared up to the midinfrared region at T=1000 K show…
The surfaces of polystyrene (PS) films decorated with gold nanoclusters were investigated by x-ray reflectivity measurements. The thicknesses of the films are much larger than the radii of gyration of the different PS samples. By annealing the films above the glass transition temperature T(g) an embedding process of t…
Rare-earth and lead ions (Eu3+, Tb3+, Dy3+, Pb2+) doped Ca2Y8(SiO4)6O2 and Ca2Gd8(SiO4)6O2 thin films have been dip-coated on silicon and quartz glass substrates through the sol–gel route. X-Ray diffraction (XRD), TG–DTA, scanning electron microscopy (SEM), atomic force microscopy (AFM), FT-IR and luminescence excitat…