Materials Literature
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It was demonstrated that the oxyfluoride NbO2F with an ReO3-type structure is a promising electrochromic material with wide band gap. Measurement of diffuse reflectance spectra revealed the optical band gap of NbO2F (∼3.1 eV) to be wider than that of WO3 (∼2.6 eV). It was rendered electron conductive by heating at 770…
The origin of the microscopic motions that lead to stress relaxation in deeply supercooled liquid remains unclear. We show that in such a liquid the stress relaxation is locally anisotropic which can serve as the driving force for the hopping of the system on its free energy surface. However, not all hoppings are equa…
We report direct transmission electron microscopy evidence of self-organized, ordered array of coherent orthogonal column nanostructures in epitaxial La0.8Sr0.2MnO3 (LSMO) thin films grown on (001) LaAlO3 (LAO) using pulsed-laser ablation. The orthogonal column nanostructures have an orthorhombic structure and are epi…
The dielectric behavior of the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compound has been studied. A low-temperature dielectric relaxation was observed in a low-permittivity matrix with ε=∼60. The dielectric relaxation process follows a modified Debye model in the vicinity of the relaxation peak, and the relaxation rat…
Direct observation of polarization distribution at nanoscale by scanning force microscopy across partially etched Pb(Zr,Ti)O3 film ferroelectric capacitors with size 2×3 μm and preferential orientation (111) has revealed an anomalous polarization pattern characterized by polarization inversion in the center of the cap…
A short enumeration of the phytoplankton composition of some lakes and ponds of Bali is given, with discussion and illustration of rare or interesting taxa (Hariotina polychorda (KORSIKOV) E. HEGEWALD, Desmodesmus komarekii (E. HEGEWALD) E. HEGEWALD, Golenkinia brevispicula E. HEGEWALD et SCHNEPF, Staurastrum bibrachi…
The effect of 5- and 10-MeV electron irradiation and subsequent annealing upon the optical absorption of ${\mathrm{CdS}}_{1\ensuremath{-}x}{\mathrm{Se}}_{x}$ quantum dots embedded in a borosilicate glass matrix is studied. Gradual smearing and vanishing of the confinement-related maxima and a blue shift of the absorpt…
We derive thermodynamical functions for some large unit cell ionocovalent crystals from the well known quasiharmonic free energy model with the help of ab initio calculations. In order to keep the computation time within reasonable bounds the ab initio assessment applies only to the cohesive energy as a function of vo…
A circular dichroic (CD) excition chirality method based on host-guest chiral recognition has been developed to determine the absolute configuration of carboxylic acids with an alpha-stereogenic center; an amide C = O-->Zn coordination, identified by infrared spectroscopy and computations, is involved in this complexa…
Dielectric loss spectra of four different glass formers revealing either beta relaxation or excess wing are presented. We compare the effect of pressure and temperature on the mentioned processes. Our findings suggest that the excess wing and the beta relaxation cannot be treated on the same footing.
We report the magnetotransport properties of epitaxial films of the full Heusler alloys Ni2MnGa, Ni2MnGe, and Ni2MnAl, grown by molecular beam epitaxy on (001) GaAs. The ferromagnetic alloys (Ni2MnGa,Ni2MnGe) exhibit an anomalous temperature dependence of the resistivity and a negative magnetoresistance peaking near t…
Use of an epitaxial conducting template has enabled the integration of epitaxial ferroelectric perovskites on silicon. The conducting template layer, LaxSr1−xTiO3 (LSTO), deposited onto (001) silicon wafers by molecular-beam epitaxy is then used to seed {001}-oriented epitaxial perovskite layers. We illustrate the via…
We have controlled in-plane stress in the CoO2 sublattice of (Ca2CoO3)xCoO2 by cationic substitution of alkaline earth metals at the Ca site. The effects of the magnitude of the stress on thermoelectric properties have been investigated by using highly grain-oriented polycrystalline thin films. The in-plane compressiv…
Vertically aligned carbon nanotube (CNT) arrays were grown on p-type silicon wafer using acetylene and iron phthalocyanine as the sources of hydrocarbons and catalysts, respectively. The CNT arrays were treated by chemical reagents, such as oxygen (O2), ozone (O3), bromine, and acids. When treated by O2 and O3, the em…
Theoretical consideration of recently proposed ordered stoichiometric and oxygen-deficient (110) surfaces of ${\mathrm{SnO}}_{2}$ crystal with $1\ifmmode\times\else\texttimes\fi{}1,$ $1\ifmmode\times\else\texttimes\fi{}2,$ $2\ifmmode\times\else\texttimes\fi{}1,$ and $1\ifmmode\times\else\texttimes\fi{}4$ symmetries ha…
The growth times of single-wall carbon nanotubes (SWNT's) within a high-temperature laser-vaporization (LV) reactor were measured and adjusted through in situ imaging of the plume of laser-ablated material using Rayleigh-scattered light induced by time-delayed, 308-nm laser pulses. Short SWNT's were synthesized by res…
Measuring three-dimensional orientational motions of many individual molecules within glassy state poly(methyl methacrylate) has enabled nanoscopic probing of bulk-obscured polymer dynamics. Complementing bulk studies, the measured distributions of nanoscale barriers to rotational motion afforded by our single molecul…
Controlled alignment of catalytically grown carbon nanofibers (CNFs) at a variable angle to the substrate during a plasma-enhanced chemical vapor deposition process is achieved. The CNF alignment is controlled by the direction of the electric field lines during the synthesis process. Off normal CNF orientations are ac…
We report on molecular dynamics studies of heat flow in superlattices. The computer simulations are performed using classical mechanics with periodic boundary conditions. The heat flow is in the direction normal to the layers. We have studied the variation of the conductivity with the repeat distance and the effect of…
Wood polypropylene composites (WPC) of different compositions (30, 40, and 50%) have been prepared using maleic anhydride–polypropylene copolymer of different percentage (5 and 10% relative to their wood fiber content). Tensile, flexural, fracture toughness, and impact test of the prepared WPC were carried out. From t…