Materials Literature
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Mixed-valence manganites Ln 1- x A x MnO 3 exhibit complicated transport behaviour resulting from complex interplays among charge, spin and lattice. In the paramagnetic phase, the carriers are trapped in localized states as small polarons due to the incorporation of three different localization features: (i) strong el…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTBis(azafulvene) as a Versatile Building Block for Giant Cyclopolypyrroles: X-ray Crystal Structure of [64]Hexadecaphyrin(1.0.1.0.1.0.1.0.1.0.1.0.1.0.1.0)Jun-ichiro Setsune and Satoshi MaedaView Author Information Department of Chemistry, Faculty of Science and Graduate…
Enzymatic synthesis of a conducting complex of polyaniline (PANI)−poly(vinylphosphonic acid) (PVP) is presented. The polymerization of aniline was carried out in an aqueous buffer at pH 4.0 using the enzyme horseradish peroxidase (HRP) as the biocatalyst in the presence of a PVP polyanion template. The formation of th…
Various chromium-containing catalysts were tested for the total oxidation of trichloroethylene (TCE) as a model reaction for the catalytic combustion of chlorinated organic pollutants. A spinel-type cobalt chromite (CoCr2O4) among others was proven to be a very promising catalyst showing higher activity and higher CO2…
We have functionalized poly( N -vinyl carbazole) (PVK) by controlled sulfonation. CdS nanocystals of 3−20 nm across were synthesized in the sulfonated PVK matrix with the CdS molar fraction of ∼1−18%. The CdS nanoparticle size increased with the molar fraction of CdS. At high CdS molar fractions, the CdS nanocrystals…
The modern multi-polaron theory predicts a polaronic Fermi-liquid state, but such a state has not been unambigously confirmed by experiment so far. Here we report theoretical and experimental studies of the isotope effects on the low temperature kinetic properties of the doped ferromagnetic manganites. Our results pro…
The study of metallomesogens has added several new dimensions to the wider field of liquid crystals. In this Account, just one family of complexes is considered, namely alkoxystilbazole complexes of various silver(I) salts. These complexes show an incredibly rich and diverse mesomorphism ranging from nematic and smect…
We present a calculation of the change of free energy of a solid surface upon bending of the solid. It is based on extracting the surface stress through a molecular dynamics simulation of a bent slab by using a generalized stress theorem formula, and subsequent integration of the stress with respect to strain as a fun…
Thin layer electrodes (0.2−0.5 μm) of highly organized nanotextured anatase were prepared by hydrolysis of TiCl 4 in the presence of poly(alkylene oxide) block copolymer, Pluronic P-123, acting as the structure-directing agent. Electrochemical properties of these layers were studied in KCF 3 SO 3 + propylene carbonate…
Palladium nanoparticles (2−3 nm in diameter) have been prepared within covalently functionalized poly(propylene imine) (PPI) dendrimers, and the resulting composite materials are shown to be effective for Heck coupling reactions. Two novel concepts are demonstrated in this report. The first concept involves the incorp…
The interrelation between particle size, crystal structure and optical properties in semiconductor quantum dots has elicited widespread interest. We report the first attempt at relating the size-induced transformation from a hexagonal to a cubic structure in CdS nanoparticles to a change in the band gap. CdS nanoparti…
Silver complexes of poly(amidoamine) (PAMAM) dendrimers as well as different {silver−PAMAM} dendrimer nanocomposite solutions have been tested in vitro against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli bacteria, using the standard agar overlay method. Both PAMAM silver salts and nanocomposite…
We demonstrate high-quality, highly fluorescent, ZnSe colloidal nanocrystals (or quantum dots) that are doped with paramagnetic Mn 2+ impurities. We present luminescence, magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) measurements to confirm that the Mn impurities are embedded inside the…
Photoluminescence in the visible domain can be observed in amorphous silicon nitride (a-SiNx) alloys prepared by evaporation of silicon under a flow of nitrogen ions. A strong improvement of the photoluminescence intensity was obtained with annealing treatments in the range 500–1150 °C. Structural investigations were…
A first-principles-derived approach is used to study the properties of rocksalt-ordered and disordered Pb(Sc0.5Nb0.5)O3 (PSN) alloys. The paraelectric-to-ferroelectric transition temperature Tc is strongly dependent on the atomic configuration, while the piezoelectric response versus T/Tc is nearly independent of the…
It is demonstrated that the nonrelativistic high energy $\ensuremath{\omega}\ensuremath{\rightarrow}\ensuremath{\infty}$ behavior of the photoionization cross section of an $\mathrm{nl}$ atomic subshell, ${\ensuremath{\sigma}}_{\mathrm{nl}}(\ensuremath{\omega})$, for $l>0$ is independent of $l$ and is given by ${\e…
Benefitting from the long path inside planar waveguides, we have investigated the optical losses of porous silicon, in the continuous 0.8–1.6 μm (0.77–1.55 eV) range. The obtained values, typically a few cm−1, are 1 order of magnitude larger than “pure” absorption losses measured previously. The other main sources of…
Mössbauer and magnetic studies have shown that 1–2 wt % of SiO2 could be dissolved in the CoFe2O4 structure. Changes in magnetization and Curie temperature were observed. The presence of SiO2 might enhance magnetic anisotropy. Coercivity values of up to 3.5 kOe were measured for mechanically alloyed CoFe2O4/SiO2 powde…
We report on the growth of polarity-controlled ZnO films by plasma-assisted molecular-beam epitaxy. Different polar (Zn- and O-polar) ZnO films on unipolar (Ga-polar) GaN epilayers are selectively grown. Polarity of ZnO films is evaluated by coaxial impact collision ion scattering spectroscopy. Zn preexposure prior to…
We show that germanium dots can be directly grown by molecular beam epitaxy (MBE) on a silicon (001) surface covered by a thin (1.2-nm-thick) thermal silicon oxide layer. We describe the experimental procedure, which induces the growth of a high density (1011/cm2) of nanometric germanium dots on silicon oxide. Germani…