Materials Literature
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The combination of hexacyanoferrate(III) anions, [Fe(CN)(6)](3)(-), with nickel(II) complexes derived from the chiral ligand trans-cyclohexane-1,2-diamine (trans-chxn) affords the enantiopure layered compounds [Ni(trans-(1S,2S)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (1) and [Ni(trans-(1R,2R)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2…
Combining analytical and theoretical methods, we present a detailed study of a heteropolytungstate cluster encapsulated in a shell of dendritically branching surfactants, namely (C(52)H(60)NO(12))(12)[(Mn(H(2)O))(3)(SbW(9)O(33))(2)], 3. This novel surfactant-encapsulated cluster (SEC) self-assembles spontaneously from…
Wave functions and electron potentials of laterally-confined surface states are determined experimentally by means of photoemission from stepped Au(111) surfaces. Using an iterative formalism borrowed from x-ray diffraction, we retrieve the real-space wave functions from the Fourier transform of their momentum represe…
The resistance of multilayers with interface roughness on a length scale which is large compared to the atomic spacing is computed in several cases via the Boltzmann equation. This type of roughness is common in magnetic multilayers. When the electronic mean free paths are small compared to the layer thicknesses, the…
We report the magnetoresistance characteristics of one-dimensional electrons confined in a single InAs quantum well sandwiched between AlSb barriers. As a result of a novel nanofabrication scheme that utilizes a 3nm-shallow wet chemical etching to define the electrostatic lateral confinement, the system is found to po…
The oxidation mechanisms of isoprene and butadiene initiated by OH in the presence of NO have been explored under “wall‐less” flowing conditions, with products observed a few seconds after reaction by infrared spectroscopy. Since only ∼1% of alkene is reacted, any secondary chemistry is negligible. The use of reaction…
Basing on peculiarities of local potentials, the two principal trends in vacancy formation are revealed. The proximity to the threshold of local ionic stability due to a giant potential contribution of electronic delocalization accounts for thermal anion vacancies typical of intrinsic semiconductors of AB type. On the…
Otherwise antiferromagnetic chromium is shown to couple ferromagnetically when doped into GaN irrespective of whether the host is a crystal or a cluster. The results on the doped clusters and crystals are obtained from density functional theory based molecular orbital theory and linearized muffin tin orbital tight bin…
We have refined the crystal structures of a Pr(0.60)Ca(0.40)MnO(3) single crystal from neutron diffraction data. The result at low temperature gives a superstructure that cannot be interpreted as Mn(3+)/Mn(4+) charge ordering. The pattern of atom displacements suggests the trapping of electrons within pairs of Mn site…
α-MnO 2 was synthesized by a very simple coprecipitation technique and tested as active electrode material for an electrochemical supercapacitor. The powder presents a poorly crystallized cryptomelane phase with a chemical composition of K 0.05 MnO 2 H 0.10 ·0.15H 2 O. Different aqueous electrolytes were tested includ…
Highly dispersed zirconium oxide species on silica exhibit fine structure in phosphorescence emission spectra showing the vibration energy of the photoactive Zr-O-Si linkage to be 955 cm-1, and the species promotes the photoinduced non-oxidative methane coupling at room temperature.
A comparative study of photoinduced birefringence in azobenzene-side-chain copolymers under continuous-wave (cw) and pulsed irradiation is presented. Absolute refractive index changes were determined by the attenuated total reflection spectroscopy. We clearly demonstrated that pulsed, similarly to cw, irradiation indu…
Nuclear quadrupole resonance (NQR) is being researched in order to confirm the presence of explosives as part of landmine sensor suites for the UK MOD hand held and vehicle mounted detection applied research programs. A low power NQR system has been developed as a non-contacting, but short range, detection method for…
Transmission electron microscopy (TEM) of a perovskite Ba0.5Sr0.5TiO3 thin film, grown on a (001) LaAlO3 substrate by pulsed-laser ablation, reveals that the film of single-crystal quality has an unusually distorted lattice with lattice parameters a and b (parallel to the interface) larger than c (perpendicular to the…
Raman spectra of aqueous Ga(III)- perchlorate, - nitrate and -sulfate solutions were measured. In Ga(III)- perchlorate solutions, a strongly polarized mode of medium intensity at 526 cm−1 and two depolarized modes at 430 cm−1 and 328 cm−1 have been assigned to v1(a1g), v2(eg) and v5(f2g) of the hexaaquagallium(III) io…
Electrophilic addition of chloroform to SWNTs followed by hydrolysis resulted in the addition of hydroxy groups to the surface of the nanotubes; further esterification with propionyl chloride led to the corresponding ester derivatives, which allowed us to identify their structure, also providing better solubility in o…
We have found a perfect thermoelastic intermartensitic transformation between the seven-layer modulation $(7M)$ and the five-layer modulation $(5M)$ martensites in an unstressed ${\mathrm{Ni}}_{52}{\mathrm{Mn}}_{24}{\mathrm{Ga}}_{24}$ single crystal. In particular, we found that the intermartensitic transformation is…
Sub-50 nm lines, holes, and posts have been patterned photolithographically using near-field embedded-amplitude masks and an exposing wavelength of 220 nm generated by an arc-lamp source. Interference in the optical near field is utilized to produce the fine patterns. In some cases, the feature sizes on the mask are m…
The effect of Ga substitution for Mn in the ferromagnetic manganite ${\mathrm{La}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ has been studied by preparing a series of ${\mathrm{La}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}{\mathrm{O}}_{3}$ $(x=0,0.10,0.25).$ Magnetic properties h…
Photoluminescence (PL) and time-resolved PL spectra of zinc oxide (ZnO) films were investigated as a function of the grain size of the microcrystals. Correlation was found between the grain size and the optical properties—in the bound exciton states, both the PL intensity and PL decay time increased with increasing th…