The phase separation behavior in a Cu–Co nanoparticle was investigated using Monte Carlo (MC) simulation. The modified embedded atom method (MEAM) was adopted to describe the interatomic potentials for the Cu–Co alloy system. Some of the cross potential parameters were fitted with experimental data such as mixing enthalpy and lattice constants of Cu–Co alloys. The present MC simulation combined with the MEAM potential describes well the phase separation between face-centered-cubic (fcc) Cu and fcc Co during the annealing of the particle.

In this paper, we report the growth of ZnO films on silicon substrates using a pulsed laser deposition technique. These films were deposited on Si(111) directly as well as by using thin buffer layers of AlN and GaN. All the films were found to have c-axis-preferred orientation aligned with normal to the substrate. Films with AlN and GaN buffer layers were epitaxial with preferred in-plane orientation, while those directly grown on Si(111) were found to have random in-plane orientation. A decrease in the frequency of the Raman mode and a red shift of the band-edge photoluminescence peak due to the presence of tensile strain in the film, was observed. Various possible sources for the observed biaxial strain are discussed.

We report the extremely high and selective uptake of selenium oxyanions by a novel anion exchanger, Ni1-xZn2x(OH)2(OCOCH3)2xnH2O (0.15<x<0.25). The tested Ni–Zn basic salt (x=0.24) exhibited very high selectivity for Se(IV) [Kd = 9.0 × 104 cm3/g with an initial Se(IV) concentration of 1 × 10-4 M] in the presence of 0.1 M C1− solution. The uptake of Se(IV) on the Ni–Zn basic salt was irreversible when treated with solutions containing 1 N C1− 1N NO3− or 1 N PO43−This novel exchanger also showed high Kd (2.6 × 103 cm3/g) for Se(VI), and therefore it is expected to be useful for decontamination and removal of selenium oxyanions from contaminated water.

In this work, the synthesis of CeO2–10 mol% Y2O3 powders by a nitrate–glycine gel-combustion route was investigated. Special attention was given to the influence of the glycine/metal ratio and calcination temperature on powder morphology. In contrast to the usual reported behavior, the best powder properties (crystallite size, 4.5–7 nm; specific surface area; 25–40 m2/g) were obtained for slow combustion processes with glycine/metal ratios of 1.5–2, whereas energetic reactions resulted in large crystallite and particle sizes. Furthermore, it was found that the crystallite size increases considerably even at moderate calcination temperatures (350–550 °C), showing the high reactivity of these nanopowders.

We report on the synthesis of carbon nanotubular structures produced for the first time by means of pulsed KrF laser ablation of a graphite pellet at high temperature (1150 °C), under high argon gas pressure (500 torr), and at relatively high ultraviolet (UV) laser intensities (8 × 108 W/cm2). The carbon nanotubular structures were directly observed by transmission electron microscopy and characterized by micro-Raman spectroscopy. Nanohorns (∼2.5 nm diameter and ∼10 nm long), a few single-wall nanotubes (1.2 to 1.5 nm diameter), and other nanotubular structures (such as graphitic nanocages and low-aspect-ratio nanotubules) were clearly observed in the carbon deposit. Raman spectra in the low-frequency range confirmed a population of tubular structures with diameters ranging from 0.7 to 2.0 nm. It is shown that the relatively high UV laser intensity used here favors the growth of various nanotubular structures to the detriment of single-wall nanotubes.

Lead lanthanum zirconate titanate (PLZT9/65/35) ceramics were prepared from their oxide mixture via reactive sintering without involving a calcination step. PLZT ceramics sintered at 1000 °C for 4 h possessed a grain size of 3–4 μm, a dielectric constant of 3670, a dielectric loss of 0.033 at 1 kHz, and a remnant polarization of 5.7 μC/cm2 and coercive field of 4.6 kV/cm, respectively. Transparent PLZT ceramics were obtained by annealing the sintered samples at 1125 °C for 6 h repeatedly for 4 times without using hot pressing or oxygen flow. The grain size of PLZT ceramics increased to 4–6 μm, with dielectric constant of 5187 and dielectric loss (1 kHz) of 0.036, and remnant polarization of 11 μC/cm2 and coercive field of 5.3 kV/cm. The transparent PLZT ceramics demonstrated a transmittance of 42% at a wavelength of 550 nm.

This communication presents the effects of nitrogen pressure on the crystallization behavior of Si3.0B1.1C5.3N3.0 ceramics annealed at 1800 °C for 3 h. Transmission electron microscopy observation reveals that increasing nitrogen pressure results in the retardation of the crystallization process. Besides SiC and Si3N4 nanocrystals, individual large crystallites were also detected. These crystals were composed only of Si and N, and they possessed hexagonal structure with lattice parameters a = 0.737 nm and c = 0.536 nm. Crystallites of this novel phase were more frequently found with increased nitrogen pressure.

The development of lead zirconate titanate (PZT)-based capacitors using common Pt electrodes has been a long-time goal of ferroelectric random access memories (FRAM).In this work, a series of Pb1−xLax(Zr0.55Ti0.45)O3 capacitors (for 0.01 < x < 0.05) having fatigue-free characteristics have been grown on Pt/ Ti/SiO2/Si substrates. Typically 2–3 mol% La-modified PZT capacitors fabricated at 580 °C by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5 × 1010 switching cycles, a low coercive field of 50–55 kV/cm, and a stable charge retention profile with time, all of which assure their suitability for the future nonvolatile FRAM.

Effects of an Al2O3 nanothin film between the emitting layer and the sputterdeposited cathode were studied for organic light-emitting diodes (OLEDs) with indium–tin–oxide, NN′-dephenyl-NN′-bis)(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine, tris(8-hydroxyquinoline)aluminum (Alq3), and aluminum (Al) as an anode, a hole transport layer, an emitting layer (EML), and a cathode, respectively. The performance of the OLEDs with sputter-deposited Al cathodes was inferior to that of the OLED with the evaporated Al cathode. However, the insertion of an Al2O3 nanothin film with a proper thickness between the EML and the sputter-deposited Al cathode was effective to alleviate performance degradation of the OLEDs with sputter-deposited Al cathodes in current flow and light emission. It is considered that both protection of EML by Al2O3 from the sputtering damage and higher luminance by the presence of a thin insulating layer between the EML and the cathode alleviated performance degradation of the OLED with an Al2O3 cathode buffer layer. The Al2O3 buffer layer could not alleviate quantum efficiency reduction caused by the sputtering damage.

In spite of their interesting properties, nanostructured materials have found limited uses because of the cost of preparation and the limited range of materials that can be synthesized. It has been shown that most of these limitations can be overcome by subjecting a material to large-scale deformation, as occurs during common machining operations. The chips produced during lathe machining of a variety of pure metals, steels, and other alloys are shown to be nanostructured with grain (crystal) sizes between 100 and 800 nm. The hardness of the chips is found to be significantly greater than that of the bulk material.

Aluminum samples were milled in a high-energy ball mill at times ranging from 10 to 500 min in stainless vial/media and nylon vial/media. The crystallite size of aluminum milled in the stainless steel setup reached a plateau at 25 nm around 100 min, whereas the crystallite size of aluminum milled in the nylon setup reached the same plateau at 500 min. Contamination studies were conducted using x-ray fluorescence, hydrogen–carbon–nitrogen analysis, and thermogravimetric analysis. Although organic contamination due to the nylon milling media was high at 12 wt% when milled for 500 min, it is shown that the contaminant could be easily removed by thermal treatment.

We report the property studies of a MgB2 superconductor with high critical current density. The MgB2 superconductor was readily fabricated through a direct high-pressure synthesis of the respective elements. The obtained high-density MgB2 undergoes a sharp superconducting transition at 39 K. The bulk critical current density (Jc) of the sample was calculated on the basis of Bean's critical state model, and rather high critical current densities over a wide temperature range were obtained in comparison with the ambient prepared samples. The results highlight that high-pressure sintering would be a promising way to produce and search for this kind of intermetallic boride and the related superconductors.

We report that polycrystalline cubic-Si3N4 with a spinel structure and low oxygen concentration (<0.5 wt%) shows Vickers hardness of 43 GPa when measured with the indentation load of 10 mN. The hardness decreases with the increase of the indentation load, which can be ascribed to the presence of weak grain boundaries. The high hardness can be well explained by its large shear modulus as predicted by first-principles calculations.

The direct observation of a type of microstructure in the organic matrix layers of nacre was obtained with a transmission electron microscope. The microstructure, which is referred to as mineral bridge in the biomineralization, is nanoscale and randomly distributed in the layers. Statistical analysis gives the distribution laws and characteristics of mineral bridges in the organic matrix layers. The existence of mineral bridges in nacre was confirmed, and it was shown that the microarchitecture of nacre should be described as a “brick–bridge–mortar” arrangement rather than traditional “brick and mortar” one.

The deposition of cobalt thin films from cobalt hydride complexes, HCo[P(OR)3]4, where R = methyl, ethyl, i-propyl, and n-butyl, by a chemical vapor deposition method is reported. The new cobalt precursors deposited high-purity cobalt films at substrate temperatures as low as 300 °C without employing hydrogen. The deposited Co films showed smooth and dense surface morphology. The microstructure and growth rate of the deposited films depended on the reaction conditions such as substrate temperature and precursor feed. No gas phase reactions were observed during the deposition process.

The chemical durability of crystalline matrices loaded with actinides can be stronglyreduced when α-decays generate enough disorder to induce a crystalline to amorphoustransition. The alpha decay of actinides in SrTiO3 (α-recoils and α-particles) was simulated using Pb and He irradiation. This study shows that the He-ion annealingprocess that operates in some apatitic structure is negligible in SrTiO3 where thedisorder evolution at room temperature has a strong sigmoid dependence on dose. Thedirect-impact/defect-stimulated model, the cascade quenching/epitaxial recrystallizationmodel, and a direct-impact/cascade-overlap model were used to reproduce the SrTiO3-disorder evolution under Pb-ion irradiation.

Y-branching multiwalled carbon nanotubes with a bamboolike structure were grown by chemical vapor deposition from a C–H–N gas system when B2O3 and Ti was supplied. Transmission electron microscopy images reveal that these novel junctions contain a tube branched into two tubes with nearly the same diameter. In addition, the tube walls show perpendicularly stacked graphite planes, which take on a bamboolike structure. The influence of preparation conditions on the structure of these carbon nanotubes is discussed. This novel structure may offer promising application for nanotube-based composites.

Single, epitaxial buffer layers of insulating LaMnO3 (LMO) or conductive La0.7Sr0.3MnO3 (LSMO) have been grown by sputter deposition on biaxially textured Ni and Ni–alloy substrates. We report baseline investigations of their compatibility with the Yba2Cu3O7−δ (YBCO) coatings and demonstrate biaxially textured YBCO films grown by pulsed-laser deposition on these single-buffered tapes. Superconducting property characterizations revealed better properties for YBCO films on LMO-buffered tapes relative to those grown on LSMO layers. Self-field critical current densities (Jc) exceeding 1 × 106 A/cm2 at 77 K have been obtained for the YBCO (200 nm) films on LMO-buffer layers. These results offer prospects for the use of single, LMO-buffered metal tapes in the development of practical YBCO-coated conductors.

The crystallographic orientation plays an important role in high-temperature oxidation of the intermetallic compound CoGa. When CoGa is exposed to air at elevated temperatures, the oxide β–Ga2O3 is formed, and different scale growth rates are observed, depending on the crystallographic orientation of the CoGa grains. This dependence is a consequence of the anisotropy of the gallium diffusion rate through the β–Ga2O3 scale and of a topotaxial orientation relationship occurring between β–Ga2O3 and CoGa. The combination of ex situ techniques, such as transmission electron microscopy and electron backscatter diffraction with optical microscopy, applied in situ resulted in a thorough understanding of these relations and of the oxidation process in general.

Low-temperature deposition of high-quality (Ba, Sr)TiO3 (BST) thin films was achieved in air on Pt/Ti/SiO2/Si substrates using the charged liquid cluster beam (CLCB) method. The Ba, Sr, and Ti precursors were synthesized using alkoxy carboxylate ligands to tailor their physical properties to the CLCB process. The as-deposited BST films fabricated at substrate temperatures as low as 280 °C exhibited high purity. The leakage current density and dielectric constant of the film, deposited at 300 °C and subsequently annealed at 700 °C, were 2.5 × 10−9 A/cm2 at 1.5 V and 305, respectively.