Materials Literature
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Processes of graphitisation of laser-irradiated polycrystalline diamond surface exposed to multipulse irradiation are studied experimentally. The thickness of the laser-modified layer as a function of the laser-pulse duration ranging from 100 fs to 1.5 μs and the effect of the radiation wavelength on this thickness ar…
An organoclay containing epoxy groups, namely twice functionalized organoclay (TFC), was successfully synthesized by reacting (glycidoxypropyl)trimethoxysilane with Cloisite25A (C25A), which had previously been modified with an amine compound. The role of the epoxy groups on the clay surface in improving the morpholog…
The surface structure of $\mathrm{MgO}(111)\text{\ensuremath{-}}(1\ifmmode\times\else\texttimes\fi{}1)$ bulk and thinned single crystals have been investigated by transmission and reflection high-energy electron diffraction, low-energy electron diffraction (LEED), and x-ray photoelectron and Auger electron diffraction…
The crystal structure and local spontaneous polarization of ${(\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_{3})}_{m}∕{(\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3})}_{n}$ superlattices are calculated using first-principles density-functional theory. The in-plane lattice constant is constrained to be 1% larger than the $\mathrm{Sr}\m…
Dielectric, anelastic, and $^{139}\mathrm{La}$ NMR relaxation measurements have been made on the relaxor ferroelectric ${\mathrm{Pb}}_{1\ensuremath{-}3x∕2}{\mathrm{La}}_{x}{\mathrm{Zr}}_{0.2}{\mathrm{Ti}}_{0.8}{\mathrm{O}}_{3}$ (PLZT) with $x=0.22$. The dielectric susceptibility exhibits the frequency dispersive maxim…
We report on a measurement procedure to separate ferroelectric switching current and dielectric displacement current from the leakage current in leaky ferroelectric thin-film capacitor structures. The ac current response is determined for two adjacent frequencies. Taking advantage of the different frequency dependenci…
The sliding friction of a dimer moving over a periodic substrate and subjected to an external force is studied in the steady state for arbitrary temperatures within a one-dimensional model. Nonlinear phenomena that emerge include dynamic bistability and hysteresis, and can be related to earlier observations for extend…
By combining an atomistic pseudopotential method with the configuration interaction approach, we predict the pressure dependence of the binding energies of neutral and charged excitons: $X^0$ (neutral monoexciton), $X^{-}$ and $X^{+}$ (charged trions), and $XX^0$ (biexciton) in lens-shaped, self-assembled In$_{0.6}$Ga…
We have prepared the oxyhydrate Na03RhO206H2O by extracting Na+ cations from NaRhO2 and intercalating water molecules using an aqueous solution of Na2S2O8. Synchrotron X-ray powder diffraction, thermogravimetric analysis (TGA), and energy-dispersive x-ray analysis (EDX) reveal that a non-stoichiometric Na03(H2O)06 net…
We show that the dynamic magnetization at the edges of a thin magnetic element with finite lateral size can be described by new effective boundary conditions that take into account inhomogeneous demagnetizing fields near the element edges. These fields play a dominant role in the effective pinning of the dynamic magne…
We report results of molecular dynamics simulations of amorphous ice for pressures up to 22.5 kbar. The high-density amorphous ice (HDA) as prepared by pressure-induced amorphization of I(h) ice at T=80 K is annealed to T=170 K at various pressures to allow for relaxation. Upon increase of pressure, relaxed amorphous…
Two series of Fe−Ce catalysts were prepared following two different methods: coprecipitation from Fe and Ce nitrate solutions and physical mixing of pure Fe and Ce precursors. Evidence of the presence of a chemical interaction between Fe and Ce was found in the calcined state of the coprecipitated catalysts. Such evid…
We report ZnO nanowire/nanowall growth using a two-step vapor phase transport method on $a$-plane sapphire. X-ray diffraction and scanning electron microscopy data establish that the nanostructures are vertically well aligned with the $c$ axis normal to the substrate and have a very low rocking curve width. Photolumin…
This review systematizes the data on the effect of intramolecular spin–orbit perturbations on the photophysics of organic molecules introduced by heavy atoms (the intramolecular, or 'internal', heavy-atom effect). The focus is on two classes of compounds: (1) halogenated derivatives of aromatic and heteroaromatic comp…
In this paper, dielectric permittivity of dielectric mixtures is discussed in view of the spectral density representation method. A distinct representation is derived for predicting the dielectric properties [Tuncer E 2005 J. Phys. Condens. Matter 17 L125]. In order to illustrate the strength of the representation and…
We have observed tunable negative differential resistance (NDR) in scanning tunneling spectroscopy measurements of a double layer of C60 molecules on a metallic surface. Using a simple model we show that the observed NDR behavior is explained by voltage-dependent changes in the tunneling barrier height.
The dielectric alpha relaxation is the dielectric manifestation of the glass transition. In spite of this fact, the more commonly used models, the Arrhenius model and the Williams--Landel--Ferry model, do not take into account the structural state of the system to modelize this relaxation. In thermally stimulated disc…
Recently an interesting multi-ferroic system PbVO3 [Chem. Mater. 2004] was successfully prepared using a high-pressure and high-temperature technique. The crystallographic features were reported. In this note we concentrate on the theoretical XANES spectra by considering the K-edge of Vanadium. The tetragonality [c/a=…
Using first principles calculations we have studied the formation energies, electron and hole affinities, and electronic levels of intrinsic point defects in zircon. The atomic structures of charged interstitials, vacancies, Frenkel pairs, and antisite defects are obtained. The limit of high concentration of point def…
We report first principles density functional studies using plane wave basis sets and pseudopotentials and all-electron linear augmented plane wave (LAPW) of the relative stability of various ferroelectric and antiferroelectric supercells of PMN $(\mathrm{Pb}{\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}{\mathrm{O}}_{3})$ for…