Materials Literature
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Two mechanisms of electrostriction in relaxor ferroelectrics of lead magnesium niobate (PMN) type are proposed. The first is based on the interaction of the soft-lattice polarization and lattice distortions with the charge transfer fluctuations and with the active ion displacements for the localized Nb–O–Nb and O–Nb–O…
Nanocrystalline Ge in SiO2 was synthesized by the reduction of Si0.75Ge0.25O2 with H2, at various annealing temperatures (ranging from 700 to 900 °C), with various H2 partial pressures (100% N2, 6% H2:94% N2, and 100% H2), and for a range of times. Cross-sectional transmission electron microscopy (XTEM) reveals a stro…
Poly(ethylene glycol):poly(acrylate) PEG-g-PA co-polymers were made that inhibited nonspecific protein and cellular adhesion. PEG-g-PA co-polymers were then covalently modified with either cell adhesion peptides or fragments of antibodies to monocyte/macrophage integrin receptors (anti-VLA4, anti-beta(1), anti-beta(2)…
Acoustic and dielectric properties of Pb(Mg1/3Ta2/3)O3 (PMT) and Ba(Mg1/3Ta2/3)O3 (BMT) single crystals with B-site disorder were obtained in a wide temperature range by micro-Brillouin scattering and dielectric spectroscopy. The temperature dependences of both the dielectric constant and the Brillouin shift of the lo…
Polarized Raman spectra of heteroepitaxial (Ba0.7Sr0.3)TiO3 thin film deposited on the (001)MgO substrate have been studied in the broad temperature range from 30 to 1300 K. Our results show that the ferroelectric–paraelectric phase transition is markedly shifted to higher temperatures with respect to the bulk ceramic…
The removal of calcium mineral deposits from metal surfaces is of practical interest for a variety of fields (i.e., food, petroleum, and chemical industries). This study investigated the mechanisms of calcite (CaCO 3 ) dissolution using environmentally benign polyaspartic acid (PASP) under controlled hydrodynamic cond…
White-blue electroluminescent emission with a voltage bias less than 10 V was achieved in rf sputter-deposited amorphous carbon nitride (a-CN) and amorphous silicon carbon nitride (a-SiCN) thin-film-based devices. The heterojunction structures of these devices consist of: Indium tin oxide (ITO), used as a transparent…
The copolymerization of epsilon-caprolactone (epsilon-CL) and d,l-lactide catalyzed by Candida antarctica lipase B was studied. Copolymerizations with different epsilon-CL-to-lactide ratios were carried out, and the product was monitored and characterized by MALDI-TOF MS, GPC, and (1)H NMR. The polymerization of epsil…
Heavy metal oxide glasses containing GeO2 were investigated as potential hosts for 1.48 μm fiber-optic amplifiers because of their low phonon energy. Addition of ⩾10 mol % GeO2 to 0.57PbO−0.25Bi2O3−0.18Ga2O3 (mole fraction) glass provided thermal stability as well as good emission properties. The optimum glass composi…
A thermodynamic approach is used to develop a framework for modeling uranium–niobium alloys under the conditions of high-strain rate. Using this framework, a three-dimensional phenomenological model, which includes nonlinear elasticity (equation of state), phase transformation, crystal reorientation, rate-dependent pl…
Complex structures of carbon nanotubes formed from a conventional carbon arc-discharge method have been revealed by high-resolution transmission electron microscopy (HRTEM). The branching and the droplet growth phenomena observed by HRTEM indicate that the formation and growth of carbon nanotubes from an arc-discharge…
The electric resistance CoFe2O4 nanocrystals of different sizes, obtained by the coprecipitation method was investigated under pressure up to 20 GPa in a diamond anvil cell at ambient temperature. The experimental results indicate that the phase transition (from the spinel to a tetragonal structure) takes place at 7.5…
The abnormal polarization offset observed in case of graded ferroelectric structures is explained assuming the presence of a nonreversible part of polarization due to the imposed polarization gradient. It is shown that an upper limit for the offset should exist, fixed by the remnant polarization of the component mater…
We report the structural, magnetic, and electrical transport properties of pervoskite oxide La0.9Te0.1MnO3. This material, with space group R-3C, shows spin-glasslike features at low temperature and has a good colossal magnetoresistance behavior. The magnetoresistance ratio MR=[ρ(0)−ρ(H)]/ρ(0) is about 51% at 200 K in…
The development of devices that combine a magnetic material with a semiconductor chip is a major focus of current research. Barium hexaferrite (BaFe12O19 or BaM) thick films are deposited here using a rf sputtering system. The films are amorphous and nonmagnetic after deposition. Postdeposition thermal annealings are…
Ferroelectric Schottky diodes were fabricated with n-type Zn0.4Cd0.6S. These devices show promising nonvolatile memory properties and the integration into complementary metal-oxide-semiconductor (CMOS) circuits seems feasible. So far, we have demonstrated on-resistances down to 100 Ω, on/off ratios up to 107, switchin…
Laser-induced weak shock formation in fused silica is studied using standard wave mechanics and applied to thin-film laser spallation experiments. Due to the negative nonlinear elasticity of fused silica, a laser-induced Gaussian stress pulse evolves into a shock after traveling a certain distance in a fused silica su…
The dynamic high-pressure behavior and phase stability of titanium–silicon carbide (Ti3SiC2), a unique ceramic having metal-like properties, was investigated in this study. Time-resolved measurements of the Hugoniot equation of state, employing a plate impact geometry, were conducted on the Ti3SiC2 samples in the pres…
The energy difference Δ E between the spin-allowed and spin-forbidden states of Tb 3+ in crystals is studied. The environmental factor h e representing the character of the host is redefined by using the chemical band of complex crystals. The relationship between h e and Δ E is found to be a linear relation. The resul…
Diffuse scattering (DS) due to the polar nanoregions in perovskite relaxor ferroelectric Pb(Zm 1/3 Nb 2/3 )O 3 with 8% PbTiO 3 was investigated by cold neutron scattering with high energy resolution (8 GHz). The anisotropy of DS near the (100) Bragg reflection cannot be explained merely by the polar character of the i…