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。
The sponge skeleton of the spine of sea urchins is found to be generated from nanocrystals 20–50 nm in size (main image). The nanocrystals make up the oriented architectures of various living species (see insets) in association with biopolymers; together they are in the form of inorganic–organic nanocomposites. This n…
We investigate the spin-Hall effect in a two-dimensional heavy-hole system with Rashba spin-orbit coupling using a nonequilibrium Green's function approach. Both the short- and long-range disorder scatterings are considered in the self-consistent Born approximation. We find that, in the case of long-range collisions,…
Results of structural neutron diffraction study, magnetization, and electron spin resonance (ESR) measurements are presented for insulating ${\mathrm{Nd}}_{1\ensuremath{-}x}{\mathrm{Ba}}_{x}{\mathrm{MnO}}_{3}(x=0.25)$ with the Curie temperature ${T}_{C}\ensuremath{\approx}129\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Det…
Using first-principles density functional calculations, we study the possible phases of CeMnNi$_{4}$ and show that the ground state is ferromagnetic. We observed the hexagonal phase to be lowest in energy whereas experimentally observed cubic phase lies slightly higher in energy. We optimized the structure in both pha…
The permeability of certain polymer membranes with impenetrable nanoinclusions increases with the particle volume fraction (Merkel et al., Science, 296, 2002). This intriguing observation contradicts even qualitative expectations based on Maxwell's classical theory of conduction/diffusion in composites with homogeneou…
Thermoelectric properties of a nanocontact made of two capped single wall nanotubes (SWNT) are calculated within the tight-binding approximation and Green's function method. It is found that semiconducting nanotubes can have high Seebeck coefficient very near the actual Fermi energy. This in turn leads to very high fi…
The amorphous conducting carbon films have been prepared at three different preparation temperatures with different boron-doping levels. The structural and transport properties of the same have been studied. X-ray diffraction measurements show that the 'd' value of the carbon depends both on atomic percentage of B in…
Magnetic and electric properties of a single crystal of ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{CoO}}_{3}$ have been experimentally studied. The system attains a ferromagnetic spontaneous moment below 170 K and exhibits a reentrant spin-glass phase below 100 K. In the ordered and the reentrant phases, the low-…
Boron doped amorphous conducting carbon films show MI transition induced by doping. In this paper we discuss the ac conductivity of the films, which lie on the insulating side of MI transition. The ac conductivity data is analyzed as a function of frequency as well as temperature for both real as well as imaginary par…
We present the results of Monte Carlo simulations of the magnetic properties of a model for a single nanoparticle consisting in a ferromagnetic core surrounded by an antiferromagnetic shell. The simulations of hysteresis loops after cooling in a magnetic field display exchange bias effects. In order to understand the…
The spin polarization of ferromagnetic alkali-metal iron antimonides KFe4Sb12 and NaFe4Sb12 is studied by point-contact Andreev reflection using superconducting Nb and Pb tips. From these measurements an intrinsic transport spin polarization Pt of 67% and 60% for the K and Na compound, respectively, is inferred which…
The spin orientation of a magnetic dopant in a zinc-blende semiconductor strongly influences the spatial structure of an acceptor state bound to the dopant. The acceptor state has a roughly oblate shape with the short axis aligned with the dopant's core spin. For a Mn dopant in GaAs the local density of states at a si…
Considering effects of electric field on the low temperature absorption line of quantum well excitons, we show that, for moderate strength of the electric field, the main contribution to the field dependence of the line-width results from field induced modifications of inhomogeneous broadening of excitons. We find tha…
In order to combine silicon technology with the functionality of magnetic systems, a number of ferromagnetic (FM) materials have been suggested for the fabrication of metal/semiconductor heterojunctions. In this work, we present a systematic study of several candidate materials in contact with the Si surface. We emplo…
Electronically active biomaterials via directed peptide self-assembly: Redox-promoted self-assembly of an eight-residue cyclic D,L-α-peptide bearing four 1,4,5,8-naphthalenetetracarboxylic diimide (NDI) side chains results in the formation of electronically delocalized peptide nanotubes hundreds of nanometers in lengt…
The poor performance of hydrogen storage materials continues to hinder development of fuel cell-powered automobiles. Nanoscale carbons, in particular (activated carbon, exfoliated graphite, fullerenes, nanotubes, nanofibers, and nanohorns), have not fulfilled their initial promise. Here we show that carbon materials c…
(2005). Combined technology of production of ceramic coatings. Welding International: Vol. 19, No. 11, pp. 894-896.
Calcite crystals often nucleate and grow in solutions of calcium carbonate, and these crystallites can become trapped at the air water interface, where they form unusual structures. The most common is a fractal structure, which can extend over a large fraction of the interface, and whose origin is understood in terms…
Abstract In this article, experimental results on the effect of CO 2 sorption and desorption on the creep response of polycarbonate (PC) are presented. Tensile specimens machined from PC sheets were exposed to CO 2 and the absorbed gas mass fraction ranged from 0.045 to 0.12. The creep/creep recovery response of as‐re…
Eu 0.58 Sr 0.42 MnO 3 is found to own a wide variety of magnetic structures, and two subsequent magnetic transitions, a PM-AFM (paramagnetic-antiferromagnetic) transition followed by an AFM-FM (ferromagnetic) transition, are observed under proper magnetic field. It is found that the thermal response of heat capacity t…