Materials Literature
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Polarized Raman spectra of oriented finely twinned ${\mathrm{CaMnO}}_{3}$ thin films and nonpolarized Raman spectra of ${\mathrm{CaMnO}}_{3}$ ceramics were studied at room temperature using several excitation laser wavelengths. The selection rules for the polarized Raman spectra, obtained from samples consisting of fi…
The experimentally measured coercive electric fields for domain reversal in ferroelectrics are typically many orders of magnitude lower than the estimates from phenomenological free-energy theory. This letter specifically investigates the influence of polarization gradients at pre-existing 180° domain walls in ferroel…
We studied the relation between the electronic structure and the phsyiscal properties of ${\mathrm{SrFe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{O}}_{3}.$ The main technique used in the study was Fe $2p,$ Co $2p,$ and O $1s$ x-ray absorption spectroscopy. The experimental spectra were analyzed in terms of the con…
We have studied the temperature (T) and field (H) dependence of the magnetocaloric effect in a bulk amorphous Pd40Ni22.5Fe17.5P20 alloy. With decreasing T, and depending on H, the alloy exhibits superparamagnetic, field-induced ferromagnetic, and spin-glass behavior. The temperature-dependence of the magnetic entropy…
Combination of nanolithography and electrochemistry allows the chemical modification of individual single-walled carbon nanotubes (SWCNTs) by attachment of functional groups. This approach allows both the reductive as well as oxidative coupling of substituted phenyl groups, presumably to defect sites in the tubes. The…
The cluster ions Aun(CO)m(O2)u− (n = 2,3; m = 1, u = 1,2) are successfully synthesized via coadsorption of oxygen and carbon monoxide onto mass-selected gold clusters inside a temperature controlled ion trap at 100 K. The investigated gold clusters Au1–3− show a significant size dependence in the reactivity toward oxy…
Formation and evolution of fragmentation instabilities in fractal islands, obtained by deposition of silver clusters on graphite, are studied. The fragmentation dynamics and subsequent relaxation to the equilibrium shapes are controlled by the deposition conditions and cluster composition. Sharing common features with…
We formulate a lattice Boltzmann algorithm which solves the hydrodynamic equations of motion for nematic liquid crystals. The applicability of the approach is demonstrated by presenting results for two liquid crystal devices where flow has an important role to play in the switching.
A novel family of photochromic hybrids, 2,3-bis(2,5-dimethyl-3-thienyl) unsymmetrical-phthalocyanines (BTE-uPcs), which show a photoregulating fluorescence switch in the near-infrared spectral region were synthesized by a concise route.
Easily obtained in a single step from bipyrrolic precursors in yields over 70 %, cyclo[8]pyrroles represent a new class of porphyrin analogues that display the classic disklike structure of porphyrins. The X-ray crystal structure of one of the cyclo[8]pyrroles obtained (see picture) shows that the macrocycle acts as a…
The thylakoid DeltapH-dependent/Tat pathway is a novel system with the remarkable ability to transport tightly folded precursor proteins using a transmembrane DeltapH as the sole energy source. Three known components of the transport machinery exist in two distinct subcomplexes. A cpTatC-Hcf106 complex serves as precu…
Carboxylate-bridged chain complexes of Co(II) (the diaquacobalt(II) mono- and ,-dialkanoates) form two homologous series of layered compounds which have been fully characterised both structurally and magnetically. The crystal structures of two selected members, [Co[CH3(CH2)10COO]2(H2O)2] and [Co[CH3(CH2)18COO]2(H2O)2]…
The relative intensities of the green and blue luminescence of a ZnO film was shown to depend on the excitation regime. Time-resolved and steady-state luminescence were studied along with photoconductivity transients. Under continuous excitation the film emitted green light, while under pulsed excitation the luminesce…
(104)-oriented Bi4Ti3O12, La-substituted Bi4Ti3O12[(Bi3.44La0.56)Ti3O12] and Nd-substituted Bi4Ti3O12[(Bi3.54Nd0.46)Ti3O12] films were epitaxially grown on (111)SrRuO3//(111)SrTiO3 substrates at 700 °C by metalorganic chemical vapor deposition. All deposited films showed strong (104) orientations. The values of the re…
This work measures the thermal conductivities along free-standing silicon layers doped with boron and phosphorus at concentrations ranging from 1×1017 to 3×1019 cm−3 at temperatures between 15 and 300 K. The impurity concentrations are measured using secondary ion mass spectroscopy (SIMS) and the thermal conductivity…
The dielectric and piezoelectric properties of the new perovskite solid solution system (1- x )BiScO 3 – x PbTiO 3 were investigated. This system is representative of a new group of high temperature piezoelectrics that includes Bi(Me)O 3 –PbTiO 3 , where Me +3 is a relatively large cation, Sc, Y, Yb, In, etc., and com…
Carbon nanotube field-effect transistors (CNTFETs) fabricated out of as-grown nanotubes are unipolar p-type devices. Two methods for their conversion from p- to n-type devices are presented. The first method involves conventional doping with an electron donor, while the second consists of annealing the contacts in vac…
Dendrimers are characterized by a combination of high end-group functionality and a compact, precisely defined molecular structure. These characteristics can be used in biomedical applications, for example, for the amplification or multiplication of effects on a molecular level, or to create extremely high local conce…
Single-wall carbon nanotubes (SWNTs) were used to augment the thermal transport properties of industrial epoxy. Samples loaded with 1 wt% unpurified SWNT material show a 70% increase in thermal conductivity at 40K, rising to 125% at room temperature; the enhancement due to 1 wt% loading of vapor grown carbon fibers is…
Single-wall carbon nanotubes (SWNTs) were used to augment the thermal transport properties of industrial epoxy. Samples loaded with 1 wt % unpurified SWNT material showed a 70% increase in thermal conductivity at 40 K, rising to 125% at room temperature; the enhancement due to 1 wt % loading of vapor grown carbon fibe…