Materials Literature
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Photoacoustic and Raman spectroscopy as well as photoluminescence (PL) measurements have been used to investigate the effect of band-gap widening in porous GaP. A correlation between a blueshift of the absorption edge observed during photoacoustic measurements, accompanied by PL emissions in the blue and ultraviolet r…
The electronic structure and properties of ferromagnetic mixed–valence manganites with the perovskite structure are briefly reviewed. The importance of disorder–induced localization is emphasized, and it is proposed magnetic disorder is effective in this sense on three different length scales. First, spin disorder on…
Doping of the Mn-site in Ln1-yAyMn1–xMxO3 manganites has been extensively investigated. For the manganites exhibiting a Curie temperature (Tc) these substitutions depress Tc. However, the effect on Tc is doping–element dependent. It decreases from dTc/dx = –25 K %–1 for M = Fe down to dTc/dx∼0 K %–1 for M = Cr in the…
We report on a type of Si interband transitions at ${\mathrm{Si}(100)\ensuremath{-}\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ interfaces that has no equivalent in the bulk of crystalline silicon. These transitions, leading to strong resonances in optical second-harmonic-generation spectra with energies of 3.6--3.8 eV, are e…
Colloidal Ag suspensions including adsorbed pefloxacin, an antibacterial agent, were studied by photon correlation spectroscopy (PCS), ζ potential measurements, UV−vis absorption, and surface enhanced Raman scattering (SERS). These techniques provide complementary information about the particle size and state of aggre…
Using a self-consistent linear combination of atomic orbitals method based on density-functional theory in a local-density approximation, the electronic structure in the high-temperature ceramics $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Si}}_{3}{\mathrm{N}}_{4}$ and $\ensuremath{\beta}\ensuremath{-}{\mathrm{Si}}_{3}…
An extended set of temperature-dependent ARUPS data from Ni(111) is presented. The ferromagnetic and the paramagnetic state as well as the phase transition are examined in great detail. Rather new and unconventional modes of data acquisition in ARUPS are applied with high angular and energy resolution, exhibiting grea…
Neutron diffraction techniques have been used to investigate the influence of applied magnetic field and pressure on the structural and magnetic phase transitions in La1–xSrxMnO3. The structural, magnetic and electronic properties are found to be strongly coupled. For suitable compositions the coupling between the mag…
Field-emission current from chemical vapor deposited diamond film on molybdenum wafer has been investigated experimentally and theoretically. The Fowler–Nordheim plot exhibits three linear regimes, corresponding to low, middle, and high electric field, respectively. A potential barrier model, based on a fact that meta…
Excited states of singlet and triplet H2Ti(μ−H)2TiH2 have been calculated using multiconfigurational wave functions. The effects of orbital relaxation are determined by optimizing orbitals for all states separately and comparing to state-averaged calculations, and are found to be small. Dynamic electron correlation in…
The electronic states of a series of ${(\mathrm{D}\mathrm{M}\mathrm{e}\ensuremath{-}\mathrm{D}\mathrm{C}\mathrm{N}\mathrm{Q}\mathrm{I})}_{2}\mathrm{Cu}$ systems with nondeuterated and partially deuterated methyl groups in a DMe-DCNQI molecule have been investigated by ${}^{13}\mathrm{C}$ NMR measurements at the cyano…
Two families of perovskites, LaMnO3+δ and R1–xMnO3–δ (R = La, Pr, Nd) have been prepared in polycrystalline form by a soft–chemistry route. The precursors were annealed at moderate temperatures either in air or under high oxygen pressure. In the strongly oxygenated LaMnO3+δ pervoskites (with nominal Mn4+ contents up t…
We present ab initio local-density-functional calculations of the atomic and electronic structure of stepped diamond (111) surfaces. The relaxation of an ideal monoatomic step with bulk-terminated terraces results in ${\mathrm{sp}}^{2}$ bonding near the step. The spacing between the surface layers is also increased. A…
The conductivities of polyaniline (PANi) composites doped with the copolymeric acids such as poly(methyl methacrylate-co-p-styrenesulfonic acid) (PMMA-co-SSA), poly(styrene-co-p-styrenesulfonic acid) (PS-co-SSA), and poly(methyl methacrylate-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (PMMA-co-AMPS) were investig…
Mutants of Escherichia coli unable to synthesize a functional pyruvate formate-lyase (PFL) are severely impaired in their capacity to grow by glucose fermentation. In a functional complementation assay designed to isolate the pfl gene from Clostridium butyricum, we fortuitously identified a gene that did not encode a…
In this study ultraviolet photoemission spectroscopy was employed to correlate the electron affinity and Schottky barrier height of Cu films on type-IIb ($p$-type) diamond (100), (111), and (110) surfaces. Furthermore, field emission measurements were correlated with the effective electron affinity of the samples. Pri…
We have measured the complex dielectric permittivity for ceramic samples of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{FeO}}_{3}$ $(0.2<~x<~0.8),$ which, unlike ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ and ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO…
Thermoelectric power (TEP) properties of carbon nanotubule bundles were measured in the range 4.2--300 K. It was found that the TEP is positive over the whole temperature range, and increases with the increase of temperature. Above 30 K it can be well described by a formula $S(\ensuremath{\mu}V)=0.181T\ensuremath{-}{(…
Electrical resistance and magnetoresistance of the HCl doped polyaniline (PANI) in aqueous ethanol medium and polyaniline–methyl cellulose dispersion (PANI–MC) has been investigated at low temperature down to 1.8 K and in magnetic field up to 8 T. The weaker temperature dependence of resistivity characterized by the r…
We present the first experimental characterization in molecular fragile glass-formers of a "prepeak" that appears significantly below the main peak of the static structure factor. The temperature and density dependences of this prepeak are studied via elastic neutron scattering experiments under high pressure (up to 3…