Materials Literature
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In order to explore the fundamental properties of one-dimensional nanostructured high-temperature superconductors and enhance their promising applications, a universal and general method for the synthesis of high-quality YBa(2)Cu(3)O(7-δ) (YBCO) nanowire arrays is developed, which involves the combination of a novel s…
Ordered porous structures for photonic application were fabricated on p- and n-type silicon by means of masking against ion implantation with Langmuir-Blodgett (LB) films. LB films from Stöber silica spheres [J. Colloid Interface Sci. 26, 62 (1968)] of 350nm diameter were applied in the boron and phosphorus ion-implan…
Abstract Platinum nanocrystals with sizes smaller than 10 nm are obtained by H 2 ‐reduction of aqueous K 2 PtCl 6 in the presence of different concentrations of poly ( N ‐vinyl‐2‐pyrrolidone; PVP: M w ≈ 360 000) at pH = 2.5–7.0. Tetrahedral Pt nanocrystals (3–10 nm) are produced with high selectivity (73–83% by number…
β-PbF 2 single crystals doped with YbF 3 (0.2% and 2%) were studied by x-ray diffraction (XRD), electron paramagnetic resonance (EPR) and optical spectroscopy. EPR revealed the presence of only one kind of paramagnetic ion Yb 3+ , in a cubic symmetry site. The optical absorption, emission and excitation spectra enable…
Material with the phase sequence $\mathrm{Sm}A\text{\ensuremath{-}}\mathrm{Sm}AP\text{\ensuremath{-}}\mathrm{Sm}CP$ is studied as an example of a system in which the spontaneous electric polarization and the molecular tilt develop independently at the $\mathrm{Sm}A\text{\ensuremath{-}}\mathrm{Sm}AP$ and the $\mathrm{S…
The Curie temperature TC of La1−zCez(Fex−yMnySi1−x)13 is decreased by adjusting the composition, and hence the itinerant-electron metamagnetic transition is observed at 5K in La0.75Ce0.25(Fe0.850Mn0.035Si0.110)13 after zero-field cooling. As a result, the La1−zCez(FexMnySi1−x)13 compounds exhibit strong magnetocaloric…
Self-assembled thin films of gold nanoparticles of 4–5nm, prepared on glass using aliphatic dithiols of different hydrocarbon chain lengths as interparticle linker molecules, have been studied by x-ray methods and dc conductivity. X-ray data revealed small spacer-dependent cluster size variations in the films. Conduct…
Shelling out: A replica technique is demonstrated for fabricating hollow SiC nanostructures of any shape (see figure) as defined by templates of pregrown ZnO nanostructure templates. The technique is based on plasma-enhanced chemical vapour deposition (PECVD) at a temperature of ≈250–300 °C. The SiC-shell nanostructur…
In the present work, microstructural transformation of carbon nanotubes (CNTs) from the “herringbone” into highly crystalline structure in an electric field was experimentally observed by using a high-resolution transmission electron microscope and the growth mechanism was modeled and discussed by using a finite eleme…
Bi 3.15 Nd 0.85 Ti 3 O 12 thin films of two different preferred orientations were sol-gel grown on Pt∕Ti∕SiO2∕Si. Using different heating rates during crystallization, either films containing 65% columnar grains with (104)∕(014) orientation or fine-grained films with a predominant c-axis orientation were obtained. Ani…
A series of first principles calculations have been carried out to investigate structural, electronic, and optical properties of BexZn1−xTe alloys for five beryllium compositions. Our results show that the lattice constant scales linearly with beryllium composition and there is a direct-to-indirect band gap crossover…
Cobalt-doped ZnO (Co2+:ZnO) films were studied by magnetic circular dichroism (MCD) spectroscopy. A broad 300K ferromagnetic MCD signal was observed between 1.4 and 4.0eV after exposure of paramagnetic Co2+:ZnO films to zinc metal vapor, attributed to low-energy photoionization transitions originating from a spin-spli…
The authors present a charge-dipole model for the calculation of the polarization of fullerenes and carbon nanotubes. By expressing the electrostatic interactions in terms of normalized propagators, the technique achieves a better consistency and an improved stability. In its most elementary form, the model depends on…
We show that aqueous dispersions of single-walled carbon nanotubes (SWNTs), prepared with the aid of nucleic acids (NAs) such as RNA or DNA, can be separated into fractions using agarose gel electrophoresis. In a DC electric field, SWNT/NA complexes migrate in the gel in the direction of positive potential to form wel…
The synthesis of RuO2 nanorods with reactive sputtering was demonstrated in this work. The synthesis process is very much like the metal organic chemical vapor deposition, except that RuO3 generated with reactive sputtering under high oxygen-to-argon flow ratio (>5SCCM∕15SCCM) (SCCM denotes cubic centimeter per…
Nd3+ dissolved in solid poly(acrylic acid) was synthesized by polymerization of the monomer partially neutralized with neodymium hydroxide in aqueous solution. The monomer modification and the coordination of ligands to Nd3+ were confirmed by 1H NMR spectroscopy. The measured oscillator strengths for transitions from…
The effect of Ni∕Au metal contact on the carrier injection and the electroluminescence of silicon quantum dot light-emitting diodes (LEDs) was investigated. An LED with an annealed Ni∕Au contact at 400°C in air showed a lower threshold voltage compared to that of an as-deposited Ni∕Au contact by forming a nickel silic…
Abstract Pressure effect studies on the spin crossover behaviour of the mononuclear compounds {Fe[H 2 B(pz) 2 ] 2 (bipy)}( 1 ) and {Fe[H 2 B(pz) 2 ] 2 (phen)}( 2 ) have been performed in the range of 10 5 Pa–1.02 GPa at variable temperatures (100–310 K). Continuous spin transitions and displacement of its characterist…
Low frequency noise power spectrum density of carbon nanotubes is presented. It is shown that the input-referred noise of carbon nanotubes increases quadratically as gate voltage is overdriven, suggesting that mobility fluctuation is the dominant mechanism contributing to the noise in carbon nanotube field effect tran…
Segmental mobility of a typical amorphous polymer, polystyrene, at the interface with a solid substrate was examined noninvasively by fluorescence lifetime measurement using evanescent wave excitation. Glass transition temperature (Tg) was discernibly higher at the interface than in the bulk. Measurements at different…