Materials Literature
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Local electronic properties of metallic-semiconducting carbon nanotube heterostructures are investigated by studying the behavior of the one-electron local density of states (LDOS) along the tubes. We determine how these properties change from the metallic to the semiconducting side of a nanotube junction. We show tha…
The magnetic properties of carbon nanohorns were investigated by electron spin resonance. Two decoupled electronic systems were found. The first one, which has a spin susceptibility linearly varying with temperature, was tentatively attributed to two-dimensional graphenelike sheets. The second contribution, showing a…
Fatigue rates in the Pb(Zn1/3Nb2/3)O3–PbTiO3 perovskite solid solution were investigated for different compositions in the rhombohedral and tetragonal phases in a variety of directions, at various field levels. It was found that the fatigue rates depend on both the ferroelectric phase and crystallographic orientation.…
Vertically well-aligned multiwall carbon nanotubes (MWNTs) were grown on nickel-coated glass substrates by plasma-enhanced chemical vapor deposition at low temperatures, below 600 °C, with and without hot filament. Acetylene and ammonia gas were used as the carbon source and a catalyst. Effects of growth parameters, s…
We have investigated two regions of manganite phase space; one where ferromagnetic (FM), metallic and charge-ordered (CO), insulating phases become the ground and high-temperature states, respectively, and the other with the reversed order. We found that the coexistence of FM and CO phases in broad temperature ranges…
Spin-glass states above room temperature have been found in (Mg, Fe){Mg,Fe,Ti}2O4 spinel ferrite thin films formed on Al2O3 (0001) and SrTiO3 (111) substrates. The films show a long-time relaxation of the magnetization in zero-field-cooled operation and a frequency dependence of the cusp temperature in ac susceptibili…
Self-consistent band-energy-structure calculations of the band-energy structure of ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ single-crystalline films grown on ${\mathrm{SiO}}_{2}$ and Si surfaces, with a thickness of about 1 \ensuremath{\mu}m, have been carried out in order to simulate thermopower behaviors. The norm-conse…
Die Kombination langlebiger, spektralreiner Emission von YbIII-Ionen mit der ausgeprägten Fähigkeit organischer Farbstoffe zur Lichtabsorption ergibt photolumineszente Lanthanoidkomplexe, die eine neue Klasse von Lumineszenzmarkern für biologisch und/oder medizinisch relevante Verbindungen sein könnten. Der gezeigte w…
Three current methods, used to evaluate exchange coupling constants in molecular magnetism, i.e., the molecular orbital (MO) model [Hay et al., J. Am. Chem. Soc. 94, 4884 (1975)], the valence bond (VB) model [Kahn and Briat, J. Chem. Soc. Trans. II 72, 268 (1976)], and the broken symmetry (BS) model [Noodleman, J. Che…
Density-functional calculations have been performed to investigate the reaction of diamond (100) surfaces with the hydrogen and methyl radical. In the present study, the plasma chemical-vapor deposition process using ${\mathrm{CH}}_{4}/{\mathrm{H}}_{2}$ gas was considered. The reactions with vapor ${\mathrm{CH}}_{3}$…
A detailed structural analysis of the $\mathrm{NiO}(111)\ensuremath{-}p(2\ifmmode\times\else\texttimes\fi{}2)$ surface by surface x-ray diffraction is presented and previous interpretations are revisited. The surface adopts the octopolar reconstruction after air annealing and a spinel-like configuration after UHV anne…
Heusler alloy Ni2MnGa thin films have been grown pseudomorphically on a relaxed NiGa interlayer on GaAs(001) by molecular-beam epitaxy. In situ reflection high-energy electron diffraction patterns, ex situ x-ray diffraction, and cross-sectional view transmission electron microscopy electron diffraction patterns confir…
We discuss the relevance of the Stillinger and Weber approach to the glass transition investigating the nonequilibrium behavior of models with nontrivial dynamics, but with simple equilibrium properties. We consider a family of 1D constrained kinetic models, which interpolates between the asymmetric chain introduced b…
Atomic level quantities are valuable tools in probing the local structural characteristics of amorphous materials. In this paper, we utilize the concept of atomic level stresses to study the problem of intrinsic stress in tetrahedral amorphous carbon. The stresses are extracted from the local energetics, based on the…
As a first step toward examination of ferromagnetic polymers and dendrimers by ab initio crystal orbital methods, we elucidated candidates for monomer units with the high-spin ground states in the previous study of Part I [J. Chem. Phys. 113, 4035 (2000)] by employing density-functional (DFT) methods using Becke’s and…
Oxide ion conductivity in La(2)GeO(5)-based oxide was investigated and it was found that La-deficient La(2)GeO(5) exhibits oxide ion conductivity over a wide range of oxygen partial pressure. The crystal structure of La(2)GeO(5) was estimated to be monoclinic with P2(1)/c space group. Conductivity increased with incre…
We have studied an alumina/zirconia interface using the all-electron projector augmented wave formalism within density functional theory. We present the electronic, structural, and energetic properties of the ${\mathrm{ZrO}}_{2}(001)/\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}(11\ifmmode\bar\els…
Two complementary strategies are presented for the anchoring of molecular palladium complexes, of cobalt or platinum clusters or of gold colloids inside the nanopores of alumina membranes. The first consists in the one step condensation of an alkoxysilyl functional group carried by the metal complex with the hydroxy g…
A series of coherently strained multilayer thin films of ${\mathrm{SrTiO}}_{3}{/\mathrm{L}\mathrm{a}}_{2/3}{\mathrm{Ba}}_{1/3}{\mathrm{MnO}}_{3}$ have been fabricated on (100) ${\mathrm{SrTiO}}_{3}$ and (100) ${\mathrm{NdGaO}}_{3}$ substrates by laser molecular-beam epitaxy. By the in-plane coherency strain the out-of…
The synthesis, structural characterisation and properties of a number of phthalocyanine-containing dendrimers are described. Peripheral substitution of phthalocyanine (Pc) with four poly(aryl ether) dendritic wedges (1st, 2nd or 3rd generation) produces materials whose properties are dominated both by the columnar sel…