Materials Literature
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We discuss some properties of surfaces in whose unit normal vector has constant angle with an assigned direction field. The constant-angle condition can be rewritten as a Hamilton–Jacobi equation correlating the surface and the direction field. We focus on examples motivated by the physics of interfaces in liquid crys…
Monodisperse spherical and mesoporous Eu-doped TiO2 phosphor particles were prepared by nonionic surfactant-assisted soft-chemistry method. It is shown that the phosphor particles possess submicron diameter of about 250nm and narrow size distribution. Under ultraviolet irradiation the particles show characteristic lum…
Individually isolated single-walled carbon nanotubes (SWNTs) are coated with a monolayer of cationic surfactant to improve the stability of their dispersions in water. After polymerizing the counterions of the surfactant, the monolayer coating is “locked in” (see figure), and the SWNTs are redispersible even after har…
CdCNi 3 is a newly synthesized superconductor with T c =2.5–3.2 K. The crystal has the same perovskite-type structure as MgCNi 3 but the lattice constant is ∼1% larger than that of MgCNi 3 . For this material, superconducting parameters, lower critical field H c1 (0), upper critical field H c2 (0), coherence length ξ(…
The scaling relation of ferroelectric hysteresis area ⟨A⟩ against frequency f and field amplitude E0 for the saturated loops of the hard lead zirconate titanate bulk ceramic takes the form of ⟨A⟩∝f−0.28E00.89, while that for the minor loops takes the form of ⟨A⟩∝f−0.43E03.19. In both cases, the scaling relations are s…
In this letter, the authors propose that photoluminescence emission in CaTiO3 is affected not only by disorder in the lattice former but also by structural disorder in the lattice modifier. Structural disorder was evaluated by Ti, Ca K-edge x-ray absorption near-edge structure experiments and by photoluminescence emis…
The temperature scaling of the dynamic hysteresis was investigated in soft ferroelectric bulk ceramic. The power-law temperature scaling relations were obtained for hystersis area ⟨A⟩ and remnant polarization Pr, while the coercivity EC was found to scale linearly with temperature T. The three temperature scaling rela…
Oxide and nitride nanotubes have gained attention for their large surface areas, wide energy band gaps, and hydrophilic natures for various innovative applications. These nanotubes were either grown by templates or multistep processes with uncontrollable crystallinity. Here the authors show that single crystal ZnO nan…
The authors have studied the magnetic properties of BaTiO3–CoFe2O4 nanostructures, which were prepared using pulsed laser deposition. Such nanostructures show a large uniaxial magnetic anisotropy with an easy axis along the pillar long direction. As the growth temperature decreases, the magnetic anisotropy increases.…
Bi ( Fe 1 ∕ 2 Cr 1 ∕ 2 ) O 3 , a recently proposed candidate multiferroic perovskite, is prepared in a bulk form by high pressure solid-state synthesis. The material is isostructural with polar BiFeO3 but is paramagnetic at room temperature due to disorder of the Fe3+ and Cr3+ cations on the B site. Mössbauer and magn…
Abstract A model for the prediction of faceted crystal shape evolution during growth or dissolution is presented. An ab initio mechanistic model for the relative growth or dissolution rates is also described for organic molecular crystal systems. The shape evolution model proves that while growing crystals evolve towa…
Two distinct, stable alignment states have been observed for a nematic liquid crystal confined in a layer with thickness of 12μm and in square wells with sides of length between 20 and 80μm. The director lies in the plane of the layer and line defects occur in two corners of the squares. The positions of the defects d…
The $R3m\text{\ensuremath{-}}R3c$ transition is in a limited phase field in the $\mathrm{Pb}({\mathrm{Zr}}_{1\ensuremath{-}x},{\mathrm{Ti}}_{x}){\mathrm{O}}_{3}$ (PZT) phase diagram and is a ferroelectric-ferroelectric phase transition that involves the coupling of a secondary displacive ferroelastic phase transition,…
Golden cage: The two smallest anionic gold cages, Au16− and Au17−, are doped with a Cu atom to give the cluster anions CuAu16− (see picture) and CuAu17−, respectively. The photoelectron spectra of CuAu16− and CuAu17− suggest that the doping does not alter the structures of the parent cages. Theoretical studies confirm…
To clarify the size effect in semiconductor nanowires with decreasing diameters but not yet reaching the quantum confinement region, single crystalline zinc oxide nanowires with diameters around 10nm are synthesized. Electrical transport measurements of these thin nanowires show significant increase in conductivity ac…
In this work a Mn doped magnetoelectric BiFeO 3 system is studied. X-ray diffraction (XRD), scanning electron microscopy, energy dispersive x-ray analysis (EDX), Mössbauer spectroscopy at room and high temperatures, differential scanning calorimetry (DSC), high temperature magnetization, dielectric constant measuremen…
The geometry of crescent-shaped noble-metal nanoparticles is systematically varied in terms of shape and size. The resulting changes in the plasmonic resonances of these structures are investigated by extinction spectroscopy revealing a rich polarization-dependent response in the near-infrared region of the electromag…
The authors have studied the magneto-optical and magnetotrasnport properties of Ga1−xMnxAs thin films with high Mn concentrations (x=12.2%–21.3%) grown by molecular-beam epitaxy. These heavily Mn-doped GaMnAs films were formed by decreasing the growth temperature to as low as 150–190°C and by reducing the film thickne…
The search for efficient semiconductor thermoelectrics has been greatly aided by theoretical modeling of electron and phonon transports in bulk materials and nanocomposites. Recent experiments have studied thermoelectric transport in thermoelectrics that are “strongly correlated” and derived by doping Mott insulators.…
Bismuth sulfide thin films have been assembled by cross-linkage nanorods on surface-functionalized Si substrate with self-assembled monolayers. Results of transmission electron microscopy and electron diffraction revealed that highly crystalline Bi2S3 nanorods grow along c-axis direction. Electrical transport properti…