Materials Literature
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We report on the optimization of the upconversion photoluminescence in films of conjugated polymers doped with platinum porphyrin. The upconversion emission was observed to take place at pump intensities as low as 0.5kW∕cm2. Comparison between the photoluminescence integral intensity of polyfluorene and ladder-type pe…
We perform analysis of the band structure, phonon dispersion, and electron-phonon interactions in three types of small-radius carbon nanotubes. We find that the (5,5) nanotube can be described well by the zone-folding method and the electron-phonon interaction is too small to support either a charge-density wave or su…
Using x-ray and neutron scattering, we have studied the structural and magnetic properties of the single-layer manganite ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{1+x}{\mathrm{MnO}}_{4}(0\ensuremath{\leqslant}x<0.7)$. Single crystals were grown by the floating-zone method at $18\phantom{\rule{0.3em}{0ex}}\mat…
The electronic properties and lattice dynamics of the sodium alanate phases have been studied by the density functional calculations. The phases include $\mathrm{Na}\mathrm{Al}{\mathrm{H}}_{4}$ (space group, $I{4}_{1}∕a$), ${\mathrm{Na}}_{3}\mathrm{Al}{\mathrm{H}}_{6}$ (space group, $P{2}_{1}∕n$), and NaH (space group…
We have assembled tin dioxide nanobelts with low-power microheaters for detecting dimethyl methylphosphonate (DMMP), a nerve agent simulant. The electrical conductance of a heated nanobelt increased for 5% upon exposure to 78 parts per billion DMMP in air. The nanobelt conductance recovered fully quickly after the DMM…
We report the preparation of arsenic doped p-type ZnO films using a Zn3As2∕ZnO target by pulsed laser deposition. Zn3As2 was used as a p-type dopant source material for arsenic doping in ZnO. The existence of As in the As-doped ZnO films was confirmed by the x-ray photoelectron spectroscopy study. The p-type behavior…
In the last decade, computational studies of liquid water have mostly concentrated on ground state properties. However recent spectroscopic measurements have been used to infer the structure of water, and the interpretation of optical and x-ray spectra requires accurate theoretical models of excited electronic states,…
The orientation-dependence of thin-crystal lattice fringes can be gracefully quantified using fringe-visibility maps, a direct-space analog of Kikuchi maps. As in navigation of reciprocal space with the aid of Kikuchi lines, fringe-visibility maps facilitate acquisition of 3D crystallographic information in lattice im…
A monophosphonate analogue of H4dota, 1,4,7,10-tetraazacyclododecane-4,7,10-tris(carboxymethyl)-1-methylphosphonic acid (H5do3aP), and its complexes with lanthanides were synthesized. Multinuclear NMR studies reveal that, in aqueous solution, lanthanide(III) complexes of the ligand exhibit structures analogous to thos…
Abstract A series of shape memory polyurethanes (SMPUs) was prepared from polycaprolactone diol (PCL) 4000, 1,4‐butanediol (BDO), dimethylol propionic acid (DMPA), triethylamine, and 4, 4′‐diphenylmethane diisocyanate (MDI), to which excess MDI or glycerin were added to obtain crosslinked shape memory polyurethanes. T…
We present a study of the structure, the electric resistivity, the magnetic susceptibility, and the thermal expansion of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Eu}}_{x}\mathrm{Co}{\mathrm{O}}_{3}$. $\mathrm{La}\mathrm{Co}{\mathrm{O}}_{3}$ shows a temperature-induced spin-state transition around $100\phantom{\rule{0…
A ringing free bit addressing scheme for magnetic memories like MRAM (magnetic random access memory) is proposed. As in standard MRAM addressing schemes the switching of a selected cell is obtained by the combination of two half-select field pulses. Numerical solutions of a single spin model of an MRAM cell show that…
A common aldehyde present in marine and freshwater diatoms, 2‐ trans , 4‐ trans‐ decadienal (A3), is involved in the wound‐activated response of diatoms to copepod grazing. Upon breakage of the diatom cell membrane, aldehydes are enzymatically produced by the rapid conversion of precursors and strongly impact copepod…
We report electrical control of the spin polarization of InAs/GaAs self-assembled quantum dots (QDs) at room temperature. This is achieved by electrical injection of spin-polarized electrons from an Fe Schottky contact. The circular polarization of the QD electroluminescence shows that a 5% electron spin polarization…
We study the morphological evolution of strained heteroepitaxial films using a kinetic Monte Carlo method in three dimensions. The elastic part of the problem uses a Green's function method. Isolated islands are observed under deposition conditions for deposition rates slow compared with intrinsic surface roughening r…
We report the results of low-temperature measurements of the specific heat Cp(T), ac susceptibility chi(T) and 23Na nuclear magnetic resonance NMR of Na2V3O7. At liquid He temperatures Cp(T)/T exhibits broad field-dependent maxima, which shift to higher temperatures upon increasing the applied magnetic field H. Below…
We show that electric field can induce spin polarization and dichroism effects in angle resolved photoemission spectroscopy (ARPES) in spin orbit coupling systems. The physical origin behind the effects essentially is the same as the spin Hall effect induced by the electric field. Since the ARPES experiments have both…
Using transmission electron microscopy (TEM) we studied $\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}$, an intriguing material that exhibits a huge dielectric response, up to kilohertz frequencies, over a wide range of temperature. Neither in single crystals, nor in polycrystalline samples, including…
We show that the resistivity rho(T) of disordered ferromagnets near, and above, the Curie temperature T_c generically exhibits a stronger anomaly than the scaling-based Fisher-Langer prediction. Treating transport beyond the Boltzmann description, we find that within mean-field theory, dρ/dT exhibits a |T-T_c|^{-1/2}…
We present experimental evidence for cooperative energy transfer from ${\mathrm{Tb}}^{3+}$ to two ${\mathrm{Yb}}^{3+}$ ions and a determination of the energy-transfer rate. Energy transfer from ${\mathrm{Tb}}^{3+}$ to ${\mathrm{Yb}}^{3+}$ was investigated by luminescence measurements on $({\mathrm{Yb}}_{x}{\mathrm{Y}}…