Materials Literature
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We present high-resolution neutron and synchrotron powder diffraction, magnetotransport, and magnetization measurements on Bi 0.5 Sr 0.5 MnO 3 . We report that, for the whole range of temperature 1.5 K⩽T⩽300 K, the sample studied exhibits coexistence of two phases. The majority phase presents charge and orbital order…
Measurements of the thermal conductivity for free-standing porous silicon layers were performed by means of an optical pump-probe experimental set-up. By transient heating due to laser pumping, a refractive index modulation was induced in the sample and, solving the heat propagation equation for inside the solid film,…
In ceramic La 1- x Ca x MnO 3 samples with 0⩽ x ⩽0.15 and the concentration of holes c = 0.18-0.22 between T = 77 and 340 K the resistivity, ρ, is shown to have an activated character both above and below the ferromagnetic Curie temperature, T C . The temperature dependence of the local activation energy, E loc ( T )…
Under selective excitation of the 3 P 0 level of the Pr 3+ ion in YPO 4 , the emission spectra and fluorescence decay curves were measured at different concentrations and temperatures. The origin of the spectral line located at 16 318 cm -1 (612.8 nm) was discussed and attributed to the 1 D 2 → 3 H 4 transition. The p…
A shell−core cluster 2 produced by depositing a self-assembled monolayer (SAM) of 6-thiohexyl-3-nitro-4-(4‘-stilbenoxymethyl)-benzoate ( 1 ) on a nanoparticulate gold colloid preserves normal solution-phase photoreactivity of the trans -stilbene and o -nitrobenzyl ether moieties, but shows quenched fluorescence. Neare…
Control over the orientation of a symmetric block copolymer lamellar morphology using a striped, chemically heterogeneous surface has been established. Films of symmetric diblock copolymers of poly(styrene- block -methyl methacrylate) solution cast onto silicon oxide substrates striped with periodic, 20 nm wide gold l…
Oppositely charged polyelectrolyte assemblies of poly(acrylic acid) and poly- l -lysine are deposited as alternate layers on cystamine-functionalized Au surfaces. Microgravimetric, quartz-crystal-microbalance, measurements and ellipsometric studies reveal a nonlinear increase in the polymer assembly thickness upon the…
Nanographite systems, where graphene sheets of dimensions of the order of nanometres are stacked, show novel magnetic properties, such as spin-glass-like behaviours and change of electron spin-resonance linewidths in the course of gas adsorptions. We investigate stacking effects in zigzag nanographite sheets theoretic…
Surface-enhanced infrared (SEIR) and surface-enhanced Raman scattering (SERS) spectroscopies are applied to the study of the adsorption on Au films of the dimethyldithiocarbamate derivative fungicides thiram and ziram. The specificity and sensitivity of both techniques in relation to the detection and surface stabilit…
A Landau-type phenomenological cluster theory for modelling the freezing process of the local polarization in relaxors is presented. On the basis of the theory, the proportion of frozen polarization in Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMNT) is calculated from the experimental dielectric non-linearity. The local polariz…
We study the phase diagram of the double exchange model, with antiferromagnetic interactions, in a cubic lattice both at zero and at finite temperature. There is a rich variety of magnetic phases, combined with regions where phase separation takes place. We identify phases, intrinsic to the cubic lattice, which are st…
A method for the simulation of electron scattering and diffraction in solids and molecules within the cluster approach is presented with explicit applications to photoelectron diffraction, electron scattering in molecules, and low-energy electron diffraction. No approximations are made beyond the muffin-tin model, and…
We present a derivation of the stress field for an interacting quantum system within the framework of local density functional theory. The formulation is geometric in nature and exploits the relationship between the strain tensor field and Riemannian metric tensor field. The resultant expression obtained for the stres…
A thiol-functionalized layered magnesium phyllosilicate material (called Mg-MTMS), prepared by a direct and cost-effective co-condensation synthesis, has been investigated as a high-capacity adsorbent for heavy metal ions. Structural characterization by powder X-ray diffraction, infrared spectroscopy, solid-state 13C…
The rate of electron transfer at carbon electrodes depends on various factors such as the structure and morphology of the carbon material used in the electrodes. With the advent of new carbon structures, such as fullerenes and carbon nanotubes, well-defined carbon surfaces have become available to probe electron-trans…
Nonequilibrium molecular dynamics simulations were used to study the structural properties and viscous response of interfaces in binary blends of symmetric polymers. The polymers were made immiscible by increasing the repulsion between unlike species. As the repulsion increased, the interface narrowed, and the fractio…
Nucleation and crystallization of isotactic polypropylene (iPP) has been simulated using molecular dynamics (MD) with and without nucleating agents. MD simulations were carried out with four iPP chains of 90, 180, 270, and 360 backbone carbons each in the presence of a number of derivatives of dibenzylidene sorbitol (…
We study the anisotropic magnetic structures exhibited by electron-doped manganites using a model which incorporates the double exchange between orbitally degenerate ${e}_{g}$ electrons and the superexchange between ${t}_{2g}$ electrons with realistic values of the Hund's coupling ${(J}_{H}),$ the superexchange coupli…
The atomic surfaces modelling technique has been used to solve the structure of the basic Ni-rich Al-Co-Ni decagonal phase. Formula Al70.6Co6.7Ni22.7, space group P10, five-dimensional unit-cell parameters: d1 = d4 = 4.752 (3) A, d2 = d3 = 3.360 (2) A, d5 = 8.1710 (2) A; alpha12 = alpha34 = 69.295 degrees, alpha13 = a…
A general kind of model with hierarchically constrained dynamics is shown to exhibit logarithmic anomalous relaxation similar to a variety of complex strongly interacting materials. The logarithmic behavior describes most of the decay of the response function.