Materials Literature
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Local piezoelectric deformation is investigated in (Pb,La)TiO3 (PLT) and Pb(Zr,Ti)O3 (PZT) thin films via scanning force microscopy (SFM) as a function of the ac voltage Vac applied between the conducting tip and the bottom electrode. Thus obtained voltage dependence of the effective piezoelectric coefficient (local p…
Low dimensional (nanowall) ZnO structures were prepared by a two-step growth method with oxygen-plasma-assisted molecular beam epitaxy, where the as-grown film was first engraved on a porous template using the oxygen plasma and then the ZnO nanowalls were grown on the template. The resonance Raman spectra showed the s…
We present results of detailed investigation of the crystal structure of Pb1−3x/2Lax(Zr1−yTiy)O3 solid solutions. In this letter our attention is concentrated on the series of solid solutions with x = 6% usually referred to as relaxor ferroelectrics. We have established the reasons for the non-cubic crystal structure…
The helical structure of uniformly aligned chiral nematic liquid crystals results in a photonic stopband for only one sense of circular polarization. The spectroscopic Stokes polarimeter is used to analyze spontaneous emission in the stopband. Highly polarized photoluminescence is found and the polarization properties…
Knowledge of the viscosity and its temperature dependence is essential to improve metallurgical processes as well as to validate theoretical and empirical models of liquid metals. However, data for metals with melting points above 2504K could not be determined yet due to contamination and containment problems. Here we…
Quaternary Heusler alloy Ni50Mn8Fe17Ga25 ribbons have been prepared by the melt-spun method. The ribbons exhibit large negative magnetoresistance (MR){=[R(H)−R(0)]∕R(0)} over a wide temperature region, particularly in the region during the martensitic phase transformation. The MR decreases significantly after annealin…
We report the preparation of ZnO nanocrystals embedded in a SiO2 matrix formed using sequential zinc and oxygen ion implantations. The optical absorption spectra and photoemission spectra of zinc implanted and zinc/oxygen coimplanted silica show that the first zinc implantation produces zinc clusters and that the subs…
Dielectric properties of water adsorbed in pure siliceous and aluminium containing mesoporous MCM-41 materials have been investigated in the frequency range from 20 Hz to 1 MHz. The dielectric spectra revealed three dispersion regions, liquid-like free water in the centre of the mesopores, an intermediate water layer…
Electromagnetic waves in an artificial medium formed by two mutually orthogonal lattices of thin ideally conducting straight wires (referred to as a two-dimensional wire medium) are considered. An effective medium approach and a full-wave method based on the dyadic Green's function and the method of moments are develo…
Thin films of layered ferroelectric oxide Bi5FeTi3O15 have been fabricated on Pt-coated Si substrates by pulsed laser deposition. Temperature-dependent Raman studies reveal the phase-transition temperature of 550 °C, consistent with other reports. A new mode at 685cm−1 is observed and ascribed to the Bi–Fe–O perovskit…
The effects of nonequally biaxial in-plane misfit strains on the equilibrium polarization states and the dielectric properties of single-domain epitaxial ferroelectric thin films are investigated by a nonlinear thermodynamic theory. The “misfit strain-misfit strain” and “temperature-misfit strain” phase diagrams for s…
The detection of nanotube carbons in solution by (13)C NMR is reported. The highly soluble sample was from the functionalization of (13)C-enriched single-walled carbon nanotubes (SWNTs) with diamine-terminated oligomeric poly(ethylene glycol) (PEG(1500N)). The ferromagnetic impurities due to the residual metal catalys…
Many molecular materials cannot be prepared as a "pure" (nonsolvate) crystalline phase by conventional crystal growth from solution due to the facile formation of solvate structures. In such cases, it may be possible to obtain the pure phase by a solid-state desolvation process, although such processes are generally a…
An experimental setup was developed for the simultaneous measurements of the electrical resistivity and the thermopower in the temperature range going from 77 up to 330K. The system combines accuracy, rapidity, few efforts for the sample mounting, and is fully automated. Pressure contacts are used for contacting the t…
The Pb 1− x La x TiO 3 powders were prepared by a sol–gel route in the composition range from x =0.0 to 0.3 in 0.05 increments. The lattice parameters of Pb 1− x La x TiO 3 ( x =0.0, 0.05, 0.10, 0.15, 0.20, 0.30) were determined by a high temperature X‐ray diffraction, and the intrinsic thermal expansion coefficients…
The reduction of vanadium oxide monolayer structures on Rh(111) has been investigated by variable-temperature scanning tunneling microscopy, low energy electron diffraction, photoelectron spectroscopy of the core levels, and the valence band, and by probing the phonon spectra of the oxide structures in high-resolution…
We report the development of all-diamond microelectrochemical devices, namely, a microelectrode array (MEA), in which a periodic array structure with well-defined diameters, distance, and hexagonal unit cell pattern is micromachined using a combination of state-of-the-art microwave-induced plasma growth and laser abla…
Glycopeptide dendrimers have been prepared bearing four or eight identical glycoside moieties at their surface (beta-glucose, alpha-galactose, alpha-N-acetyl-galactose, or lactose), natural amino acids within the branches (Ser, Thr, His, Asp, Glu, Leu, Val, Phe), 2,3-diaminopropionic acid as the branching unit, and a…
ZnO particles embedded in SiO2 thin films were prepared by a radio-frequency magnetron sputtering technique. X-ray diffraction (XRD) and optical-absorption spectra showed that ZnO particles with hexagonal wurtzite structure had been embedded in the SiO2 matrix, and the size of ZnO particles increased with increasing a…
The effect of LiF sintering aid on the degradation of transparent magnesium aluminate spinel during hot‐pressing was studied. LiF is used to etch spinel particles during the hot pressing process. The LiF was found to react with the aluminum in the spinel structure, thereby leaving Mg‐rich regions behind that do not si…