Materials Literature
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10-Benzyl-9,10-dihydroanthracen-9-ols, having high electron densities in the benzene ring, exhibit in the presence of acid a transannular ring closure to the corresponding homotriptycenes in almost quantitative yields. Since the starting compounds are easily accessible from 9(10H)-anthracenone, this process represents…
The interest in studying the electrical properties of WO(3) x H(2)O powders is made absolutely necessary because their infrared modulation properties depend on their morphologies and electronic populations. Broadband dielectric and resistivity spectra of WO(3) x H(2)O powders were recorded in a frequency range of 10(3…
Liquid crystal phases formed by bent-shaped (or "banana") molecules are currently of great interest. Here we investigate by Monte Carlo computer simulations the phases formed by rigid banana molecules modeled combining three Gay-Berne sites and containing either one central or two lateral and transversal dipoles. We s…
The in-plane dielectric response of [110] oriented Ba0.60Sr0.40TiO3 epitaxial films grown on [100] NdGaO3 is used to determine the field induced polarization at 10GHz. The nonlinear polarization curve is used to determine the linear and nonlinear permittivity terms for the in-plane principal directions, [001] and [1¯1…
Oxygen cycling of Sr2Fe2–xMoxO6–δ (SFMO) samples allows the resistivity and low-field magnetoresistance (LFMR) to be precisely cycled. TEM shows that the change in resistivity with oxygen is not only a consequence of the change in oxygen stoichiometry of SFMO, but also a concomitant change in the Fe/Mo ratio in SFMO.…
We investigate the electronic structure of $\mathrm{Ba}\mathrm{Ir}{\mathrm{O}}_{3}$, an interesting compound exhibiting charge density wave transition in its insulating phase and ferromagnetic transition at the same temperature, using full potential linearized augmented plane wave method within the local spin density…
We present the use of total internal reflection (TIR) evanescent waves for lithography purposes. In particular, we focus our attention on their singular capabilities to nano-structure surface relief gratings and the potentialities for nano-photonic device fabrication. Interference of two (or more) evanescent waves ach…
We have carried out a series of ab initio calculations to investigate changes in the structural and magnetic properties of pristine cobalt clusters upon CO chemisorption. Our results show that binding energies of CO to 13-55 atom (0.5-1.5 nm) cobalt nanoparticles and preferred chemisorption sites depend on the cluster…
Transport properties of manganese oxides suggest that their colossal magnetoresistance (CMR) is due to percolation between ferromagnetic metallic (FM) clusters in an antiferromagnetic insulating (AFI) matrix. We have studied small-angle neutron scattering under an applied magnetic field in CMR ${\mathrm{Pr}}_{1\ensure…
The application of diamond to dosimetry is desirable because of its tissue equivalence, chemical inertness and small size, but this has not been commercially viable owing to the non-reproducible response of natural diamond. The chemical vapour deposition (CVD) of diamond permits controlled, reproducible and large-scal…
The performance of a blue-light-emitting polymer (LEP) device is improved by introducing a novel soluble hybrid hole-injection layer based on a polyarylamine (pTPD) doped with a large inorganic magnetic cluster (Mn12) used as oxidant. The efficiency of the devices at different luminances changes dramatically as the Mn…
We report an atomic-scale study on the ferromagnetic insulator manganite ${\mathrm{LaMnO}}_{3.12}$ using $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ perturbed angular correlation spectroscopy. Data analysis reveals a nanoscopic transition from an undistorted to a Jahn-Teller (JT) distorted local envi…
Preparation of polyelectrolyte multilayer (PEM) films at fluid interfaces between aqueous solutions and liquid crystals is described. The orientation of the liquid crystals is coupled to the presence and organization of the PEM films (see figure). The PEM films can selectively mediate the interactions between solutes…
Parallel or polar strands of beta-peptides spontaneously form nanotubes of different sizes in a vacuum as determined by ab initio calculations. Stability and conformational features of [CH3CO-(beta-Ala)k-NHCH3]l (1 < or = k < or = 4, 2 < or = l < or = 4) models were computed at different levels of theory (e.g., B3LYP/…
The influence of static electric field on the transport properties in La0.7A0.3MnO3 (A=Ca,Ba) epitaxial thin films was investigated by using field effect configurations (FEC). A single layer manganite film was deposited on LaAlO3 (LAO) substrate by pulsed laser deposition technique, and then a simple FEC was formed on…
Abstract Summary: Poly(ether imide) (PEI) membranes were modified with a linear low‐molecular weight (PETIM_0.6) and a branched high‐molecular weight poly(ethylene imine) (PETIM_60). The membrane surfaces became more hydrophilic and the zeta potentials were shifted from negative to positive zeta values after immobilis…
Enhanced radiative recombination in a periodically nanoengineered silicon- on-insulator structure (see figure and cover) is studied using micro-Raman, photoluminescence, and photocurrent spectroscopies. It is shown that the enhancement is due to phonon- localization effects, leading to a relaxation of the fundamental…
The magnetic entropy change in three different polycrystalline Ni53+xFe20−xGa27 (x=0.5,1,2) alloys was analyzed as a function of temperature under different applied magnetic fields. The temperature dependence of the ac magnetic susceptibility (χ) and the magnetization of the alloys have been used to characterize the d…
Mesoporous thin films containing organic functionalities behave like selective membranes. Titania mesoporous films with an accessible cubic mesostructure are deposited on a conductive electrode (see figure). Organic groups (phenyl, hexadecyl, glycerol) are added to the pore surface by post-grafting. The transport prop…
The dielectric tunability of ferroelectric/paraelectric bilayers and multilayer superlattices are examined theoretically. A numerical analysis is carried out for a pseudomorphic (001) BaTiO3∕SrTiO3 heteroepitaxial bilayer on (001) SrTiO3 and a stress-free BaTiO3∕SrTiO3 bilayer. We show that these structures are capabl…