Materials Literature
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Abstract In a differential absorption experiment the induced infrared transitions from the excitonic 1s to the 2p levels in Cu 2 O have been investigated. Intermediate densities of 1s excitons were created by cw‐laser excitation while the interexcitonic 1s to 2p transitions were probed simultaneously, using Fourier sp…
Abstract The synthesis and characterisation (X‐ray structure and magnetism) of metal complexes (Ni, Au) with the [Mn(Cp*) 2 ] + cation and the dmit 2− and dmid 2− ligands are reported. [Mn(Cp*) 2 ][Ni(dmit) 2 ] ( 1 ) and [Mn(Cp*) 2 ][Au(dmit) 2 ] ( 2 ) exhibit the same structural arrangement, built on stacks of [Ni(dm…
At high temperatures both the resistivity $(\ensuremath{\rho})$ and thermopower of ${\mathrm{La}}_{1\ensuremath{-}x}{M}_{x}{\mathrm{MnO}}_{3}$ $(M=\mathrm{Ba},$ Sr, Ca) single crystals can be described well by a small-polaron hopping model. The polaron binding energy decreases while the orbital ordering transition ${(…
Abstract Poly(diethylsiloxane) and its copolymers with various kinds of R 1 R 2 SiO (R 1 = R 2 = methyl or phenyl, or R 1 = methyl and R 2 = phenyl) units have been prepared by the equilibrium polymerization of cyclosiloxanes. All the polymers have been characterized by 1 H and 29 Si NMR, gel permeation chromatography…
Abstract A 2 NiMoO 6 (A = Sr, Ba) perovskites have been prepared in polycrystalline form by thermal treatment, in air, of previously decomposed citrate precursors. These materials have been studied by X‐ray (XRD) and neutron powder diffraction (NPD) data. At room temperature, the crystal structure is tetragonal, space…
Abstract Synthetic biodegradable aliphatic polyester (BAP) intercalated into organoclay was prepared by melt compounding, and its solidlike characteristics were investigated via several rheological test modes: steady shear rotation, oscillation, and creep testing. Structural investigations with X‐ray diffraction and t…
We report infrared and Raman spectroscopy results of the spin-1/2 quantum magnet TiOCl. Giant anomalies are found in the temperature dependence of the phonon spectrum, which hint to unusual coupling of the electronic degrees of freedom to the lattice. These anomalies develop over a broad temperature interval, suggesti…
We present molecular dynamics simulations of solid NaNO$_2$ using pair potentials with the rigid-ion model. The crystal potential surface is calculated by using an \emph{a priori} method which integrates the \emph{ab initio} calculations with the Gordon-Kim electron gas theory. This approach is carefully examined by u…
We study the dynamics of flat circular permalloy nanomagnets for 1.) magnetic vortex and 2.) single-domain configurations, using micromagnetic simulation. Dynamical studies for isolated vortex structures show that both the vorticity and the central polarity of the out-of-plane component can be switched fast (50-100 ps…
The electronic and atomic structures of several $(1\ifmmode\times\else\texttimes\fi{}1)$ terminations of the (110) polar orientation of the ${\mathrm{SrTiO}}_{3}$ surface are systematically studied by first-principles calculations. The electronic structure of the two stoichiometric SrTiO and ${\mathrm{O}}_{2}$ termina…
We report an experimental study of the time dependence of resistivity of a La$_{0.9}$Sr$_{0.1}$MnO$_{3}$ ultrathin film in order to elucidate the underlying mechanism for metal-insulator transition and colossal magnetoresistance CMR effect. There is a clear change of sign in the resistive relaxation rate across the me…
Equilibrium spin configurations and their stability limits have been calculated for models of magnetic superlattices with a finite number of thin ferromagnetic layers coupled antiferromagnetically through (non-magnetic) spacers as Fe/Cr and Co/Ru multilayers. Depending on values of applied magnetic field and unaxial a…
Fluorine-19 NMR solution measurements have been made for various phenyl-fluorinated iron porphyrin complexes. Large chemical shifts for phenyl fluorine signals of iron(III) and iron(II) are observed, and these signals are sensitive to electronic structure. The chemical shift differences in ortho-phenyl fluorine signal…
The title polyoxometalate (POM), A-a-[Si(NbO2)3W9O37〕7-(A-a-1)1 was shown to have potent anti-HIV-1 activity (median effective antiviral concentration against HIV-1 in human peripheral blood mononuclear cells (PBMC), EC50, -1 /IM) while being minimally cytotoxic (median inhibitory concentration, IC50, >100 p.M also in…
Measurement of refractive indices in the spectral bands 9-11 microm and 1.32 microm from a cw CO2 laser and a Q-switched Nd:YAG laser, respectively, is reported in a ZnGeP2 crystal. A new set of Sellmeier dispersion relations has been derived from the measured refractive indices data in this crystal. Second-harmonic g…
Using stochastic conformal mapping techniques we study the patterns emerging from Laplacian growth with a power-law decaying threshold for growth $R_N^{-γ}$ (where $R_N$ is the radius of the $N-$ particle cluster). For $γ> 1$ the growth pattern is in the same universality class as diffusion limited aggregation (DLA) g…
Using stochastic conformal mappings we study the effects of anisotropic perturbations on diffusion limited aggregation (DLA) in two dimensions. The harmonic measure of the growth probability for DLA can be conformally mapped onto a constant measure on a unit circle. Here we map $m$ preferred directions for growth of a…
DW Tomlin, LV Natarajan, VP Tondiglia, RL Sutherland, TJ Bunning; Morphology of Holographic Polymer Dispersed Liquid Crystal Reflection Gratings Written in
We report Raman investigations on stable and metastable phases of cyanoadamantane plastic crystal, which gives an orientational glassy state upon a deep undercooling below 175 K. The isothermal transformation of the metastable quenched plastic phase is systematically analyzed for quenches in the 180−250 K temperature…
Experimental observation of the transformation of cubic symmetry from face-centred cubic (f.c.c.) to body-centred cubic (b.c.c.) for spherical microdomains upon uniaxial stretching of poly(1,3-cyclohexadiene)- block -poly(ethylene-co-but-1-ene)- block -poly(1,3-cyclohexadiene) triblock copolymer, having φ PCHD = 0.293…