Materials Literature
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Uniformly dispersed copper oxide nanoparticles in poly(vinyl alcohol) (CuO−PVA) have been synthesized by the sonochemical method. The properties of the as-prepared composite material are characterized by XRD, DSC, thermogravimetric analysis (TGA), TEM, and diffuse reflection spectroscopy (DRS). A band gap of 2.1 eV is…
Nanoparticles with high photoluminescence quantum yield have been recently considered as possible biolabels and as emitters in optoelectronic devices. Now gram amounts of nontoxic, chemically stable LaPO4:Ce,Tb nanocrystals (see picture) have been obtained in a coordinating solvent. These nanoparticles can be easily r…
The electrochemical behavior of a film of single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups was studied extensively on a glassy carbon (GC) electrode. One stable couple corresponding to the redox of the carboxylic acid group, which was supported by XPS and IR experiments, was observed. Th…
In this paper, we explore the optical properties of Ag nanoparticles chemically modified with alkanethiol self-assembled monolayers (SAMs) by measuring the localized surface plasmon resonance (LSPR) spectrum using UV−vis extinction spectroscopy. For all the experiments presented here, the Ag nanoparticles were fabrica…
The temporal shape evolution of CdSe quantum confined nanorods (quantum rods) in nonaqueous solvents with organometallic precursors was studied quantitatively and systematically. The experimental results revealed three distinguishable stages in the shape evolution. At high monomer concentrations, nanocrystals grow exc…
Spin dynamics of ceramic ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ with $x=0,$ 0.05, and 0.15 and the relative ${\mathrm{Mn}}^{4+}$ concentration $c=0.18--0.22$ is investigated by measurements of the ac susceptibility and the relaxation of the thermoremanent magnetization (TRM). The ${\ensu…
A promising class of optical filters is introduced, based on diffraction at small apertures. The filters consist of straight pores with diameters in the micrometer regime and a length of up to one millimeter through a silicon wafer. In contrast to Bragg, Woods, or glass filters, the light is not transmitted in matter…
Fatigue-free and highly c-axis oriented Bi3.25La0.75Ti3O12 (BLT) thin films were grown on Pt/Ti/SiO2/Si(100) substrates using metalorganic solution decomposition. Films annealed above 500 °C were characterized by strong c-axis preferential growth with an in-plane alignment of grains. The BLT film capacitors with a Pt…
ZnS films were grown on Si (100) at high temperatures by pulsed laser deposition using a KrF excimer laser. The growth temperature was varied from 200 to 700 °C and all films were found to have a specific preferential orientation. With increasing Ts, growth rate decreased but the quality of the film improved. The high…
Dispersions of silica spheres (aerosil) in octylcyanobiphenyl (8CB) liquid crystal were investigated with deuteron NMR. For the lowest silica density dispersions, there is a field-induced liquid crystal alignment as the field anneals most elastic strains. Increasing the silica density, the molecular alignment is stabi…
The luminescence from a planar metal–alumina–metal structure was investigated under ac voltage application in vacuum. Two kinds of electrode contacts, i.e., with/without sputtered gold film, showed quite different optical phenomena. For the nonsputtered alumina samples, no luminescence was detected until extremely irr…
We have studied the effects of Cr substitution in the perovskite La0.67Sr0.33MnO3 on the magnetic, electrical transport, and magnetoresistance properties. Cluster glass behaviors have been observed in the La0.67Sr0.33Mn1−xCrxO3 system. The most interesting feature is that extraordinary transport and colossal magnetore…
We report on complex admittance measurements on ZrO2:Y2O3 (YSZ) thin films in the parallel plate geometry. Highly textured YSZ thin films, grown by rf sputtering, allow measuring complex admittance free of the effect of charge blocking at grain boundaries. We have examined low-temperature (close to room temperature) r…
Enhancement of the emission from SrTiO3:Pr3+ by addition of group-IIIb ions (IIIb3+) has been investigated. From the photoluminescence (PL) spectra and x-ray diffraction patterns, it is speculated that one of the origins of the enhancement is charge compensation of Pr3+ at the Sr2+ site by IIIb3+ substituting for Ti4+…
We investigate the phase behavior of a two-dimensional suspension of charge stabilized polystyrene spheres in the presence of a one-dimensional periodic light field. With increasing light intensity we observe a liquid-solid followed by a solid-liquid transition which are known as laser-induced freezing and melting, re…
Tetrahedral amorphous carbon (ta-C) films deposited by the filtered vacuum arc process have large compressive residual growth stresses that depend on the atomic-bond structure. We observed that the G peak of the Raman spectrum shifts to higher frequency by 4.1±0.5 cm−1/GPa due to the residual compressive stress. This…
Dielectric Ba0.6Sr0.4TiO3 thin films were epitaxially grown on (001) MgO by using pulsed laser ablation. Microstructure studies from x-ray diffraction and electron microscopy suggest that the as-grown films are c-axis oriented with an interface relationship of 〈100〉BSTO//〈100〉MgO. A room temperature coupled microwave…
We derive a phenomenological continuum saltation model for aeolian sand transport that can serve as an efficient tool for geomorphological applications. The coupled differential equations for the average density and velocity of sand in the saltation layer reproduce both known equilibrium relations for the sand flux an…
A self-consistent calculation of the electronic properties of GaAlAs:Mn magnetic semiconductor quantum well structures is performed including the Hartree term and the sp-d exchange interaction with the Mn magnetic moments. The spin polarization density is obtained for several structure configurations. Available experi…
One-dimensional quasilattices, namely, the geometrical objects to represent quasicrystals, are classified into mutual local-derivability (MLD) classes. Besides the familiar class, there exist an infinite number of new MLD classes, and different MLD classes are distinguished by the inflation rules of their representati…