Materials Literature
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The magnetoresistance and resistance relaxation after a discontinuous field change of (LCMO) and thin film structures was investigated. We compare the magnetoresistance and resistance relaxation of epitaxial films, polycrystalline films, mechanically induced grain boundaries and heterostructures in current-perpendicul…
The transport and magnetic properties of A-site-deficient perovskite have been investigated. The electrical conductivity displayed a thermally activated temperature dependence between 200 and 300 K with an activation energy of 0.17 eV. The thermopower measured over a similar temperature range showed little temperature…
We have investigated the effects of Mn impurities on Ba0.7Sr0.3TiO3 thin films using x-ray photoemission spectroscopy. Mn acts as an electron acceptor, compensating for the charge density found in nominally undoped films. This causes a greatly increased depletion width in acceptor-doped films. We also present evidence…
X-ray microbeam techniques (spot size=3×20 μm2) have been applied to characterize the composition and structure of rare earth activated Gd(La, Sr)AlO3 phosphor thin films grown by combinatorial synthesis. Using x-ray fluorescence, x-ray diffraction and near-edge x-ray absorption spectroscopy, we have measured the chem…
The fatigue properties of the sol–gel derived Pb0.99[(Zr0.6Sn0.4)1−XTiX]0.98Nb0.02O3 (40/100X/2) thin films deposited on platinized silicon substrates were investigated as a function of Ti content (0.03⩽X⩽0.15). With an increase of Ti content X, the antiferroelectric phase was transformed to the ferroelectric phase an…
The thermoelectric figure of merit is calculated for a compound material comprising thin semiconductor and wider metallic layers. The layers are perpendicular to the direction of current. The semiconductor barriers exclude electrons with energies ε<μ from the current. This exclusion increases thermopower. One m…
Intense short-wavelength photoluminescence (PL) observed at room temperature from thermal SiO2 films co-implanted with Si and C is reported. A flat Si profile was first implanted, followed by 1100 °C annealing for 60 min. C ions were subsequently used to be implanted into the same depth region. PL was observed from th…
Photoemission spectra of polycrystalline CdO have been measured under excitation with monochromatic x-rays and with variable energy UV radiation from a synchrotron source. Experimental data are compared with density of states profiles calculated by periodic Hartree-Fock and density functional methods. Both calculation…
Amorphous “diamond-like/quartz-like” composites a-(C:H/Si:O) constitute a novel class of diamond-related materials with a number of unique bulk and surface properties. Using a thermal imaging microscope we have determined the thermal conductivity (κs) of a-(C:H/Si:O) films deposited on Si(001) substrates. We have deve…
The charge ordering in , which occurs on cooling the ferromagnetic metallic ground state, is readily destroyed on application of a magnetic field of 6 T. For , for which the ground state is charge ordered, on the other hand, magnetic fields have no effect on the charge ordering. In order to understand such a marked di…
A scaling theory describing the strength of lamellar materials is developed. The theory is based on the premise that dislocation pileups are responsible for the yielding behavior of the lamellar material. The theory is developed in terms of four parameters: The pileup length, the exponent characterizing the divergence…
We study statistical properties of energy spectra of a tight-binding model on the two-dimensional quasiperiodic Ammann-Beenker tiling. Taking into account the symmetries of finite approximants, we find that the underlying universal level-spacing distribution is given by the Gaussian orthogonal random matrix ensemble,…
The surface deformation induced by a Gaussian laser beam on azobenzene polymer film reveals strong polarization dependence and establishes that an optical field component in the direction of the intensity gradient is essential for the deformation process. The experimental results allow us to infer the phase relationsh…
We show that light emission from different systems of silicon nanocrystals does behave as expected for indirect-band-gap quantum dots. Photoluminescence excited on the low energy part of the distribution of Si nanocrystals exhibits a set of narrow peaks associated with Si TA and TO momentum-conserving phonon-assisted…
We directly measure the equilibrium length scale of dynamic heterogeneities close to the glass transition by means of a new multidimensional NMR experiment. The spatial information is gained from a proton spin diffusion experiment combined with two 2D ${}^{13}\mathrm{C}$ exchange sequences via appropriate back and for…
Abstract With the development of a number of new HT/HP fields in the North Sea, for example the ETAP fields (Eastern Trough Area Project), a number of important "scale" control issues have arisen. In addition to harsh downhole conditions (T - 180 C; P - 13,000 psi), high salinity formation water chemistries indicate t…
The growth mechanisms and physical properties of the orthorhombic crystal form of beef liver catalase were investigated using in situ atomic force microscopy (AFM). It was observed that the crystals grow in the <001> direction by an unusual progression of sequential two-dimensional nuclei of half unit-cell layers corr…
Abstract This paper presents field results from two scale squeeze treatments carried out on the same sub sea horizontal well from a field in the North Sea, The initial squeeze was a bullhead application of phosphonate scale inhibitor to control a sulphate scale problem in a horizontal well. Ten months after the initia…
A novel polymer with quasi-one-dimensional structure of ethylenediamine bridged polymeric manganese phthalocyanine [PcMn(eda)]n was synthesized by complexing of manganese phthalocyanine (MnPc) and ethylenediamine (eda). The structure of the polymer was identified by infrared, ultraviolet–visible, and differential scan…
Enantiotropic liquid crystal (LC) polyurethanes were synthesized for the first time. Thermotropic LC copolyurethanes PU n T( m / p )s ( n, the number of methylene unit, 6, 8, and 11; m, meta-type unit; p, para-type unit) were synthesized by polyaddition of 4,4‘-bis(ω-hydroxyalkoxy)biphenyls (BPn) with two kinds of dii…