Materials Literature
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Pretilt angle measurable by using the conventional crystal rotation method is limited to about 0°–20° and 70°–90°. We propose a method by which we can measure the pretilt angle by using the crystal rotation method even if the pretilt angle is between 20° and 70°. In this method, the determination of a pretilt angle is…
We numerically study a nondisordered lattice spin system with a first order liquid–crystal transition, as a model for supercooled liquids and glasses. Below the melting temperature the system can be kept in the metastable liquid phase, and it displays a dynamic phenomenology analogous to fragile supercooled liquids, w…
The electronic structures and interface properties of the TiO2/Cu2S interface have been in situ studied after each growth step by x-ray and ultraviolet photoelectron spectroscopy. The p-doped Cu2S films (BEVBM=0.1 eV) were grown on the highly n-doped chemical vapor deposition prepared TiO2 (BEVBM=3.4 eV) films by ther…
We show that the near surface structure of lamellar ABC triblock copolymer mesostructures can deviate considerably from the “ideal” surface anticipated from the bulk structure of the material. Varying the molecular architecture and the surface energy difference between the respective blocks, we show that such surface…
Abstract The influence of the electron beam modification of a dual‐phase filler on the dynamic mechanical properties of styrene‐butadiene rubber (SBR) is investigated in the presence and absence of trimethylol propane triacrylate or triethoxysilylpropyltetrasulfide. Electron beam modification of the filler results in…
The hexagonally perforated layer (HPL) phase in a polystyrene- b -poly(ethylene oxide) (PS- b -PEO) diblock copolymer was systematically studied by small-angle X-ray scattering (SAXS) in reciprocal space and transmission electron microscopy (TEM) in real space. Detailed crystallographic analyses revealed that the shea…
Negative index of refraction materials have been postulated for many years but have only recently been realized in practice. In the microwave region these materials are constructed of rings and wires deposited on a dielectric substrate to form a unit cell. We have constructed, experimentally characterized, and simulat…
Ferromagnetic behavior of GaN doped with Mn (Ga1−zMnzN) grown by the ammonothermal and chemical transport methods is discussed in terms of a second phase (ferromagnetic one) produced during the growth process. The reference manganese nitride samples grown by the same method as (Ga,Mn)N reveal room-temperature ferromag…
The electronic structure and structural stability of the technologically interesting material NaAlH4 are studied using an ab initio projected augmented plane-wave method for different possible structure modifications. We predict that α-NaAlH4 converts to β-NaAlH4 at 6.43 GPa with a 4 % volume contraction. Both modific…
First-principles electronic structure methods have been used to calculate the ground state, transition temperature, and thermodynamic properties of magnetic excitations in spinel ${\mathrm{MnO}}_{2}.$ The magnetic interactions are mapped onto a Heisenberg model whose exchange interactions are fitted to results of firs…
The temperature dependence of the overall rate constant for the C 3 H 7 O 2 + NO reaction and the rate constant for the minor branching channel resulting in the production of i -C 3 H 7 ONO 2 have been measured using the turbulent flow technique with high-pressure chemical ionization mass spectrometry for the detectio…
We apply first-principles calculations to study the electronic structure of boron nitride nanocones with disclinations of different angles θ=nπ/3. Nanocones with odd values of n present antiphase boundaries that cause a reduction of the work function of the nanocones, relative to the bulk BN value, by as much as 2 eV.…
We present a dynamic Monte-Carlo model involving lateral interactions and different adsorption sites (top, fcc and hcp). Using this model in combination with kinetic parameters from UHV experiments and lateral interactions derived from DFT calculations we have reproduced the ordering behavior of NO on Rh(111) during a…
Single crystals of Zn doped lithium ferrite have been obtained by an improved flux method. The magnetic anisotropy and Mössbauer spectra of the system (Fe1−x3+Znx2+)[Fe(3+x)/23+Li(1−x)/2+]O4 with 0⩽x⩽0.5 have been investigated. According to the single-ion model, the magnetic anisotropy constant K1 depends mainly on th…
Green, blue, and yellow cathodoluminescence (CL) have been obtained for thin-films of Ba2B5O9Cl doped with Tb3+, Tm3+, and Mn2+, respectively. These phosphor films were deposited by spray pyrolysis, and then activated in air at temperatures suitable for use on glass substrates. The CL characteristic peaks of the films…
Bi 1.5 ZnSb 1.5 O 7 dielectric ceramic with pyrochlore structure was investigated by impedance spectroscopy from 400 to 750 °C. Pyrochlore was synthesized by the polymeric precursor method, a chemical synthesis route derived from Pechini’s method. The grain or bulk resistance exhibits a sensor temperature characterist…
Co–Zr–B alloys have been produced by melt-spinning followed by heat treatments. The magnetic properties of the Co–Zr–B melt-spun ribbons depend on the annealing temperature. The maximum energy product of the optimally annealed Co–Zr–B melt-spun ribbons (BH)max=4.74 MGOe, is comparable to those of the hard ferrites. Th…
The high temperature electrical behavior of highly epitaxial CaCu3Ti4O12 thin films on (001) LaAlO3 have been systematically investigated with traditional four-probe dc and ac resistance measurement techniques and two-probe ac impedance spectroscopy. Both ac and dc resistance measurements reveal that the Arrhenius plo…
Abstract The dielectric properties and the structure of various metal–polymer composites, based on a polymer matrix of polyamide (PA), polyethylene (PE), polyoxymethylene (POM), or blend PE/POM filled with dispersed iron (Fe) particles, have been investigated in this work. In PE–Fe, PA–Fe, and POM–Fe composites the fi…
We have performed ab initio studies of the effect of substitutions on the phase stabilities of Ti1−xAlxN, x=0−1. The nonmetal substitutions studied include B, C, O, and Si. Metal substitutions studied include Sc, Zr, V, Cr, and Mn. The main objective has been to suggest substitutions that increase the thermal stabilit…