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。
Magnetotransport properties of an 80 nm-thick high quality epitaxial film of SrRuO 3 grown on SrTiO 3 (001) were investigated. The film has tetragonal structural symmetry ( c -axis ⊥ film plane), and shows a uniaxial strong magnetic anisotropy with the easy axis along the c -axis. Magnetotransport phenomena are also u…
The origins of two types of electromigration failure models are explored starting with the basic transport differential equations including the effects of electromigration-induced mechanical stress. We compare the results of a nucleation model, in which failure is determined by the time required to build up a critical…
The charge ordering process of a mixed valence LuFe 2 O 4 system has been studied, focusing attention on the frustration effect associated with the charge configuration. It is revealed that the system undergoes successive phase transitions following the sequence of disorder→2D CDW→3D CDW. In the 2D-CDW state, the char…
Molecular wires 2 are formed by the stacking of Sn triangles 1 in BaSn3. The balanced interplay of interactions between localized and delocalized structural components is responsible for the super-conductivity of 2. The “fingerprint” in the band structure of this superconductor is discussed with the help of partial el…
A high‐spin ground state characterizes the cubane complex, which was obtained from copper( II ) acetate monohydrate and the bridging ligand 2‐(4‐hyroxysalicylidenamino)ethanol. In the crystal these cubane clusters are arranged to give a channel structure (depicted on the right), which is attributed to a hydrogen‐bondi…
Hydrothermal syntheses in fluoride medium readily yield very open materials, as the example of ITQ-3 demonstrates. This new polymorph of silica with the formula [SiO2]64 has a framework characterized by a low density (16.3 SiO4 tetrahedra per 1000 Å3), a very large void volume (0.23 cm3 g−1), and a two-dimensional sys…
We have investigated the morphology of lamellar polystyrene-polymethylmetha cry late diblock copolymers in the ultrathin-film limit, spin-cast and annealed on silicon nitride substrates. Our experiments show evidence for a morphology change from lamellar domains parallel to the substrate to perpendicular domains that…
Amorphous carbon films with high sp3 content were deposited by magnetron sputtering and intense argon ion plating. Above a compressive stress of 13 GPa a strong increase of the density of the carbon films is observed. We explain the increase of density by a stress-induced phase transition of sp2 configured carbon to s…
A study of the electronic structure of about thirty transition-metal sulphides (TMS) of various stoichiometries and crystal structures is presented, supplementing recent studies of their structural and cohesive properties (P Raybaud, G Kresse, J Hafner and H Toulhoat, preceding paper). The electronic structure of the…
The structural and cohesive properties of more than thirty transition-metal sulphides of various stoichiometries and crystal structures have been investigated using density functional theory, with the aim of establishing a correlation between the strength of the metal - sulphur bond and the catalytic activities of the…
Amorphous silicon ($a$-Si) networks have been generated from melted Si with various quenching rates by molecular-dynamics (MD) simulations employing the Tersoff potential. The cooling rates were set between $5\ifmmode\times\else\texttimes\fi{}{10}^{11}$ and $1\ifmmode\times\else\texttimes\fi{}{10}^{14}\mathrm{K}/\math…
A systematic study of the magnetic properties of the manganites Ln0.5(A,A′)0.5MnO3 (A,A′=Ba, Ca, Sr) has been carried out. The variations of TC and TN vs two parameters, the average size of the interpolated cations 〈rA〉 and the mismatch effect represented by the variance σ2, have been studied for the series of mangani…
In Ce-doped $R{\mathrm{MnO}}_{3}$ the rare earth $(R)$ is partially replaced with cerium ions instead of divalent alkaline-earth metals. These compounds are very sensitive to annealing. The resistivity and thermoelectric power (TEP, $S)$ of ${R}_{0.7}{\mathrm{Ce}}_{0.3}{\mathrm{MnO}}_{3}$ ($R$=La, Pr, and Nd) have bee…
Michael additions, Knoevenagel condensations, and epoxidation of enones with H2O2 can be catalyzed under mild conditions with a new mesoporous base. Equation (a) shows the principle for a Michael addition (X = CN, Y = CO2Et); the catalyst is obtained by immobilization of a guanidine base in MCM-41.
We report results on the direct observation of the microscopic origins of backswitching in ferroelectric thin films. The piezoelectric response generated in the film by a biased atomic force microscope tip was used to obtain static and dynamic piezoelectric images of individual grains in a polycrystalline material. We…
We report on dielectric susceptibility measurements for the glass-forming systems toluene and 1-propanol, both of which exhibit slow secondary relaxation (Johari β-process). We present a complete lineshape analysis for both α- and β-process covering the real and imaginary parts. The observation of secondary relaxation…
The nonrelativistic energy loss suffered by fast electrons passing near dielectric interfaces of arbitrary shape is calculated by solving Poisson's equation using the boundary-charge method. The potential induced by a moving electron is expressed in terms of surface-charge distributions placed at the interfaces. These…
We report an ab initio evaluation of the surface energy of a simple metal, performed via a coupling-constant integration over the dynamical density-response function. The rapid rate of change of the electron density at the surface is treated exactly. Long-range correlations are treated self-consistently in the random-…
We describe quantitative imaging of the sheet resistance of metallic thin films by monitoring frequency shift and quality factor in a resonant scanning near-field microwave microscope. This technique allows fast acquisition of images at approximately 10 ms per pixel over a frequency range from 0.1 to 50 GHz. In its cu…
The homoepitaxial growth of initially flat surfaces has so far always led to surfaces which become rougher and rougher as the number of layers increases: even in systems exhibiting ``layer by layer'' growth the registry of the layers is gradually lost. We propose that pulsed glancing-angle sputtering, once per monolay…