Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Up to third-generation metallodendrimers can be constructed by a repetitive sequence of reactions with building blocks that contain two coordinatively unsaturated Pd centers (“pie” shape) and one labile, coordinating cyano group (▴, see representation below). The key steps of assembly are the displacement of the chlor…
Detailed theoretical studies of the temperature dependence of EPR g-factor for the MgO: crystal have been made by considering both the static contribution due to the thermal expansion of crystal and the vibrational contributions due to the electron - phonon (including the acoustic and optical phonons) interaction. The…
We report measurements of the low-frequency optical response in epitaxial thin films of La0.67Ca0.33MnO3 in the temperature range covering both the ferromagnetic metallic state and the paramagnetic insulating state. We observe a bolometric optical response in fully oxygenated films of the above composition as well as…
A characteristic length scale of the structure of a thixotropic colloidal clay suspension of discotic texture was demonstrated by static light scattering. The length scale, of the order of a micron, corresponds to a fractal dimension that increases from 1 to 1.8 close to a critical volume fraction. Simultaneously, the…
Chen has recently shown how the response matrix of a two-phase composite can be written as linear combinations of products of the component matrices. We elaborate on Chen's expansions by deriving them in a different way, which a. shows them in a different light, and b. permits us to generalize them further. As an appl…
The stability of the $A$-type antiferromagnetic order and canted magnetic structure of LaMn${\mathrm{O}}_{3}$ perovskite is explained in the itinerant-electron picture based on the local-spin-density approximation. We demonstrate the crucial role of the observed lattice distortion which strongly affects the magnetocry…
A new route to the successful arc-discharge synthesis of pure boron nitride (BN) nanotubes is presented. The carbon-free plasma is established between ${\mathrm{HfB}}_{2}$ electrodes in a nitrogen atmosphere. This technique leads to the formation of BN nanotubes with very few layers including single- and double-layer…
Abstract Although there are no fundamental factors hindering the development of nanoscale structures, there is a growing realization that “engineering down” approaches, in other words a reduction in the size of structures generated by lithographic techniques below the present lower limit of roughly 1 μm, may become im…
A magnetic strip with rectangular cross section and infinite extension in the third, easy direction is used as a vehicle to explore numerical micromagnetic algorithms. The manifold of (meta-)stable domain wall solutions is calculated as a function of the thickness of the strip and of the relative strength of the magne…
Polycrystalline Cr2O3 films are prepared by normal pressure chemical vapour deposition (CVD), and electrical and optical properties of the films are investigated. The films are transparent from 800 to 1000 nm wavelength, and absorbing for wavelengths shorter than 800 nm. The optical band gap energy is Eopt = 2.98 to 3…
Copper oxide thin films were prepared by reactive rf magnetron sputtering of a pure copper target in an oxygen-argon atmosphere. The phases of the deposited films strongly depend on the oxygen content in the sputtering gas. X-ray diffraction studies show that by controlling the oxygen partial pressure single phase Cu2…
Changes in microstructure induced by heat treatments between 1000 and 1500 °C in Si3N4 based glasses and ceramics were characterized using x-ray diffraction and Raman scattering. The presence of free silicon appears to be a common feature of these families of materials. Si precipitates were observed by transmission el…
CdTe nanocrystals embedded in a sodium borosilicate matrix, obtained by a sol-gel process, present a wurtzite (hexagonal) structure. Low-temperature photoluminescence and absorption spectra are measured for samples containing bulklike nanocrystals large enough to suppress confinement effects. Thus, the fundamental fre…
A non-separation approach to determine the spark-processed porous silicon thermal parameters is presented. This thermal characterization was performed through application of the photoacoustic technique, in combination with compositional models for spark-processed porous silicon samples. The thermal parameters obtained…
The spatial distributions of the secondary-electron emission sites and energies at these emission sites in Si have been simulated by a Monte Carlo method. These spatial distributions are found to be nonuniform and can be described by multifractal analysis, which is performed with a box-counting method. The results of…
A generalization of the kinetic lattice gas model is used to study the coverage and temperature dependence of the sticking coefficient due to intrinsic and extrinsic precursors and in the presence of lateral interactions.
An angle-resolved photoemission (PE) study is performed on graphite intercalation compounds (GIC's) with Eu and Yb prepared in situ by deposition of the pure metals onto single-crystalline graphite(0001) surfaces and subsequent annealing. The low-energy-electron-diffraction patterns reveal a sharp (\ensuremath{\surd}3…
The room-temperature electrical conductivity of tensile-drawn and oriented poly(p-phenylenevinylene), PPV, doped with sulfuric acid (${\mathrm{H}}_{2}$${\mathrm{SO}}_{4}$) is approximately ${10}^{4}$ S/cm for current along the draw direction; the anisotropy ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{\ensuremath{\paralle…
A large negative magnetoresistance (MR) sharply peaked at the first-order Verwey transition temperature ${T}_{V}=119.79\ifmmode\pm\else\textpm\fi{}0.02$ K has been measured in a synthetic single crystal of magnetite ${\mathrm{Fe}}_{3(1\ensuremath{-}\ensuremath{\delta})}{\mathrm{O}}_{4}$, $\ensuremath{\delta}=0.0006$.…
The inter-\ensuremath{\pi}-band response function of a single-layer carbon nanotube is calculated within the random-phase approximation. Such a cylindrical system exhibits rich inter-\ensuremath{\pi}-band excitations. The decoupled \ensuremath{\pi} plasmons of different angular momenta (L's) strongly depend on the tra…