Materials Literature
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Polymer/clay nanocomposite materials based on poly(propylene- graft -maleic anhydride) (PPgMAH) and two different organophilic modified clays were investigated by dielectric relaxation spectroscopy (DRS). In contrast to ungrafted polypropylene (PP), PPgMAH shows a dielectrically active relaxation process which can be…
Modulations in manganites attributed to stripes of charge/orbital/spin order are thought to result from strong electron-lattice interactions that lock the superlattice and parent lattice periodicities. Surprisingly in La1-xCaxMnO3 (x>0.5,90 K), convergent beam (3.6 nm spot) electron diffraction patterns rule out charg…
The crystal structure and growth mechanism of silver nanorods prepared by a seed-mediated surfactant method using the cationic surfactant cetyltrimethylammonium tosylate (CTAT) and its wormlike micelles are characterized by conventional and high-resolution transmission electron microscopy. Depending on the nanorod ori…
In this work we give the analysis of the low frequency dielectric response of selected kaolinitic clays at different water content ranging from dry, over plastic to liquid limit. For all samples investigated, depending on the moisture content, the real part of the dielectric function reflects the abnormal behaviour wi…
Abstract In semiconductor nanocrystals the electronic energy gap is determined not only by the material but also by the size of the nanocrystals. This allows the construction of an energy‐gap gradient normal to multiple layers of nanocrystals where the diameters of the nanocrystals are monotonically increasing or decr…
[reaction: see text] On the basis of an efficient Pd-catalyzed triarylation to a vinylsilane platform, four types of structurally well-defined triarylethene-based extended pi-systems have been prepared very rapidly. From a compound library constructed by the present method, it was possible to find a number of interest…
The vibrational spectrum of Mg(3)Al(2)Si(3)O(12) pyrope is calculated at the Gamma point by using the periodic ab initio CRYSTAL program that adopts an all-electron Gaussian-type basis set and the B3LYP Hamiltonian. The full set of frequencies (17 IR active, 25 RAMAN active, 55 silent modes) is calculated. The effect…
In situ high-pressure energy dispersive x-ray diffraction experiments on polycrystalline powder TiN with NaCl-type structure have been conducted with the pressure up to 30.1 GPa by using the diamond anvil cell instrument with synchrotron radiation at room tempearture. The experimental results suggested that an isostru…
We use Molecular Dynamics combined with Dissipative Particle Dynamics to construct a model of a binary mixture where the two species differ only in their dynamic properties (friction coefficients). For an asymmetric mixture of slow and fast particles we study the interdiffusion process. The relaxation of the compositi…
We have investigated the magnetic and chemical properties of very thin Cr films, CrAs, and arsenized Cr grown by molecular beam epitaxy on Ga As (001), using x-ray photoemission spectroscopy and SQUID magnetometry. Distintic preparation procedures have been used with the purpose to undestand the origin of the ferromag…
Cross sectional scanning tunneling microscopy (XSTM) and density functional theory have been used to characterize the structure of GaSb digitally doped with Mn. The Mn dopants are found in both isolated substitutional form as well as in large clusters of zinc-blende MnSb commensurate with the surrounding GaSb matrix.…
The basic mechanism underlying electric field switching produced by a resonant tunnelling diode (RTD) is analysed and the theory compared with experimental results; agreement to within 12% is achieved. The electro-absorption modulator (EAM) device potential of this effect is explored in an optical waveguide configurat…
Heat conduction of a real quasi-one-dimensional material, the finite length carbon nanowire inserted into the single-walled carbon nanotube (SWNT), has been studied by the molecular dynamical method, in which both of the longitudinal as well as transverse motions of the chain atoms in the SWNT have been permitted. It…
We have investigated ab initio the existence of localized states and resonances in abrupt GaAs/Si/GaAs (110)- and (100)-oriented heterostructures incorporating 1 or 2 monolayers (MLs) of Si, as well as in the fully developed Si/GaAs (110) heterojunction. In (100)-oriented structures, we find both valence- and conducti…
A new scheme of first-principles computation for strongly correlated electron systems is proposed. This scheme starts from the local-density approximation (LDA) at high-energy band structure, while the low-energy effective Hamiltonian is constructed by a downfolding procedure using combinations of the constrained LDA…
A simulation study demonstrates that localization can arise as the result of the breakdown of stable quasi-crystal-like atomic configurations. Samples produced at elevated quench rates and via more energetic processes contain a lower fraction of such configurations and exhibit significantly less pronounced localizatio…
We show that there is a fundamental difference between spin Hall current and orbital angular momentum Hall current in Rashba- Dresselhaus spin orbit coupling systems. The orbital angular momentum Hall current has a pure topological contribution which is originated from the existence of magnetic flux in momentum space…
SRR metamaterial is used as a substrate material in a microstrip guided wave structure to determine what the effect is of a material with potentially excessive dispersion or loss or both. A Green's function method readily incorporates the metamaterial permittivity and permeability tensor characteristics. Ab initio cal…
We investigate the transport properties of three-terminal carbon-based nanojunctions within the scattering matrix approach. The stability of such junctions is subordinated to the presence of nonhexagonal arrangements in the molecular network. Such ``defective'' arrangements do influence the resulting quantum transport…
The resistivity model as a function of temperature and ionization energy (doping) is derived with further confinements from spin-disorder scattering in ferromagnetic phase. Magnetization and polaronic effects capture the mechanism of both spin independent and spin-assisted charge transport of ferromagnets, including t…