Materials Literature
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An in situ Raman spectroscopic study was conducted to explore the pressure-induced phase transformation of Sr2CaWO6 to pressures of 50.8 GPa and room temperature. Group theory yields 24 Raman active modes for Sr2CaWO6, of which 17 are observed at ambient conditions. Upon elevation of pressure to 3.2 GPa, the results s…
The series of the SrTi(1-x)Co(x)O(3-delta) polycrystalline samples has been prepared via solid-state reaction in air. The structural study shows that a solid solution exists for all compositions, such as 0 < or = x < or = 0.9, which discards the presence of ferromagnetic and metallic cobalt clusters for the low level…
At temperatures below the metal–insulator transition of La 1− x Sr x MnO 3 with 0.1 < x < 0.15, a peculiar ferromagnetic and insulating phase is observed which has been intensively discussed over the last few years. We present a detailed investigation of this phase by means of resonant and high energy x-ray scattering…
We investigated the temperature-dependent optical absorption spectra of LaMnO 3 and NdMnO 3 epitaxial thin films. We found that both spectra have strong absorption features around 2 eV, and that the 2 eV peak of LaMnO 3 has a weak temperature dependence. As the La ions are replaced with Nd ions, the spectral weight of…
Colossal magneto-resistance manganites are characterized by a complex interplay of charge, spin, orbital and lattice degrees of freedom. Formulating microscopic models for these compounds aims at meeting two conflicting objectives: sufficient simplification without excessive restrictions on the phase space. We give a…
We present high-temperature powder x-ray diffraction data of the orbital-order-induced structural distortion of RMnO 3 , with R a rare earth element. The associated phase transition takes place in a temperature interval of ≈200 K in which the orbitally ordered phase and the orbitally disordered phase coexist. We analy…
The synthetic approach to the new class of mesomorphous nanocomposite polymer systems was developed. It is based on the in situ reduction of silver ions in the liquid crystalline (LC) polymer matrix leading to the formation of nanoparticles with typical sizes in the range of 5-30 nm. The influence of silver nanopartic…
Highly ordered hexagonal arrays of latex spheres on highly ordered pyrolytic graphite (HOPG) have been prepared from a Langmuir-Blodgett-like (LB-like) technique using both polymers and surfactants as spreading agents. The role of spreading agent concentration in forming a well-ordered, stable monolayer at the air-liq…
A family of new meso-arylsulfanyl- and alkylsulfanyl-substituted porphyrins were efficiently synthesized from direct reactions of meso-brominated porphyrins with thiols via palladium-mediated C-S bond formation. The catalytic method can be performed under mild conditions with both mono- and bis-substituted meso-bromop…
This paper reports the first detailed study on meso-unsubstituted azuliporphyrins, an important family of porphyrin-like molecules where one of the usual pyrrole rings has been replaced by an azulene subunit. Although the azulene moiety introduces an element of cross-conjugation, zwitterionic resonance contributors wi…
Previous studies on conjugated polymer nanotubules, prepared by the template method, established that improvements in the molecular and supermolecular structure are responsible for the increase in the room temperature conductivity when the diameter decreases. Our study clearly indicates that a more complex situation c…
Sapphyrins are an important group of expanded porphyrins that show valuable anion binding characteristics. In this study, a "4 + 1" route to sapphyrin systems has been developed. Reaction of dialdehydes with a known tetrapyrrole intermediate 11b incorporating a bipyrrolic subunit afforded a wide range of sapphyrin-typ…
We report the observation of photoluminescence from single-walled carbon nanotubes (SWNTs) dispersed in a tetrahydrofuran(THF)/octylamine solution, providing the first clear evidence for individual SWNTs in nonaqueous solution. We also report the effective amine-assisted dispersion of C 60 and La@C 82 peapods. This so…
Titanate compounds have been recognized as key materials for understanding the coupling of magnetism and orbitals in strongly correlated electron systems. In the perovskite Ti oxide R TiO 3 (where R represents the trivalent rare-earth ions), which is a typical Mott–Hubbard insulator, the Ti t 2 g orbitals and spins in…
The conformational changes of bovine heart cytochrome c (cyt c) induced by the adsorption on gold nanoparticles with different sizes have been investigated by electronic absorption, circular dichroism (CD), and Fourier transform infrared spectra. The combination of these techniques can give complementary information a…
The usual approach to the development of new nonlinear dielectric materials focuses on the search for materials in which the components possess an inherently large nonlinear dielectric response. In contrast, based on thermodynamics, we have presented a first-principles approach to obtain the electrostriction-induced e…
Poly(methyl methacrylate) (PMMA) has been modified via a dc pulsed oxygen plasma for different treatment times. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS), optical profilometer, zeta potential, and advancing contact angle measurements. The measured advancing contact angles of wa…
Isotropic nearly zero thermal expansion (i.e., negligible volume change) is reported in a large temperature range for Fe[Co(CN)6], a member of the Prussian blue family with electronically active metal sublattices and a cubic framework structure built by a cyanide-bridged network of octahedral units. Suitable selection…
We have built up a computer simulation of the detection mechanism in the diamond radiation detectors. The diamond detectors can be fabricated from a chemical vapour deposition polycrystalline diamond film. In this case, the trapping-detrapping and recombination at the defects inside the grains and at the grain boundar…
The biomimetic polymerization of acrylamide (1) with hydrogen peroxide catalyzed by water soluble iron(III) 5,10,15,20-tetrakis-(2,6-dichloro-3-sulfonatophenyl)porphyrin (3) gave high yield of polyacrylamide (2) in the molecular weight range of 1,30,000-1,50,000 g mol -1 in the absence and presence of 2,4-pentanedione…