Materials Literature
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On the basis of a new modified base-catalyzed sol−gel process and a careful investigation in the structure, this study systematically discussed the effects of the calcining temperature on the microstructure and luminescent properties of europium-doped strontium aluminates (SAO-E). A phase transformation from Sr 3 Al 2…
Fatigue-free and highly c-axis oriented Bi4−xPrxTi3O12 (BPrT, x=0.85) thin films were grown on Pt/TiO2/SiO2/Si (100) substrates using the method of metalorganic sol decomposition. The BPrT film capacitor with a top Pt electrode showed significantly improved values of the remanent polarization (Pr) and the nonvolatile…
The homologous series M(TCNQ) 2 (M = Mn(II), Fe(II), Co(II), and Ni(II); TCNQ = 7,7,8,8-tetracyanoquinodimethane) prepared from reactions of [M(CH 3 CN) 6 ][BF 4 ] 2 and [ n -Bu 4 N][BF 4 ] in CH 3 CN has been carefully analyzed from the perspective of synthetic issues and physical characterization, including complete…
Nanotechnology enables the fabrication of wire-grid polarizers (WGP) in the visible optical region. At oblique angles of incidence, WGP can be used as polarizing beam splitters (PBS). As such, they have the advantages of large numerical aperture and high-extinction ratios in both transmission and reflection. Because o…
This article studies transverse sound wave propagation in individual multiwall carbon nanotubes. The present model predicts that there exist (N-1) critical frequencies (within terahertz range) for an N-wall carbon nanotube. When the frequency is below all critical frequencies, vibrational mode is almost coaxial and th…
The optical dielectric functions for polarization perpendicular and parallel to the c-axis (optical axis) of pulsed-laser-deposition grown wurtzite MgxZn1−xO (0⩽x⩽0.29) thin films have been determined at room temperature using ellipsometry for photon energies from 1 to 5 eV. The dielectric functions reveal strong exci…
Bilayers of media for which the permittivity and permeability tensors are indefinite—that is, not all principle elements possess the same sign—can be used to construct low-, high-, and bandpass spatial filters. These filters possess sharp adjustable roll-offs, and can operate both below and above free-space cutoff to…
We observe that a 2-D single crystalline layer of spherical diblock copolymer domains templated by lateral substrate topology melts via a continuous defect generation process, similar to that predicted by Kosterlitz, Thouless, Halperin, Nelson, and Young. The layer of spheres is allowed to order (or disorder) by annea…
A new method for direct evaluation of both crystalline structure, bulk modulus B_0, and bulk-modulus pressure derivative B'_0 of solid materials with complex crystal structures is presented. The explicit and exact results presented here permit a multidimensional polynomial fit of the total energy as a function of all…
The temperature T and magnetic field H dependence of the resistivity $\ensuremath{\rho}$ has been measured for ${\mathrm{La}}_{0.8\ensuremath{-}y}{\mathrm{Sr}}_{0.2}{\mathrm{MnO}}_{3}$ $(y=0$ and 0.128) films grown on (100) ${\mathrm{SrTiO}}_{3}$ substrates. The low-temperature $\ensuremath{\rho}$ in the ferromagnetic…
The amount of ionized Mn acceptors in various p-type Mn-doped GaAs epilayers grown at high (Ts=580 °C) and low (Ts=250 °C) substrate temperatures has been evaluated by electrochemical capacitance-voltage measurements, and has been compared systematically with concentrations of incorporated Mn atoms and holes for a wid…
We report a clear correspondence between changes in the Curie temperature and carrier density upon annealing in epitaxially grown (Ga,Mn)As layers with thicknesses in the range between 5 and 20 nm. The changes are dependent on the layer thickness, indicating that the (Ga,Mn)As–GaAs interface has importance for the phy…
We report Curie temperatures up to 150 K in annealed Ga1−xMnxAs epilayers grown with a relatively low As:Ga beam equivalent pressure ratio. A variety of measurements (magnetization, Hall effect, magnetic circular dichroism and Raman scattering) suggest that the higher Curie temperature results from an enhanced free ho…
We experimentally determine ensemble-averaged responses of granular packings to point forces, and we compare these results to recent models for force propagation in a granular material. We used 2D granular arrays consisting of photoelastic particles: either disks or pentagons, thus spanning the range from ordered to d…
We report room-temperature time-integrated and time-resolved photoluminescence (PL) measurements on a nominally undoped wurtzite ZnO thin film grown on (001) silicon. A linear and sublinear excitation intensity Iex dependence of the PL intensity were observed for the 379.48-nm exciton line and the weak broad green ban…
The appropriate heat treatment of the Gd5Si2Ge2 alloy prepared from high-purity Gd results in a considerable enhancement of its magnetocaloric effect. The maximum magnetic entropy change increases by ∼80% (from ∼20 to 36 J/kg K) and the adiabatic temperature change increases by ∼55% (from ∼11 to 17 K) for a magnetic f…
The direct synthesis of hydrogen peroxide from H2 and O2 using a range of supported metal catalysts is described and discussed. A detailed study of the factors influencing the formation and decomposition of hydrogen peroxide is presented for a Pd/sulfonated carbon catalyst in a methanol/water solvent. The use of low t…
We measure two-dimensional profiles of collimated microwave beams transmitted through composite wire and split-ring resonator prisms. Prior experiments suggest these structures have a negative index of refraction, though these claims have been questioned. Our 2D measurements demonstrate that transmission obeys Snell's…
The manganese oxides of general formula RE 1− x M x MnO 3 (RE = rare earth, M = Ca, Sr, Ba, Pb) have remarkable interrelated structural, magnetic and transport properties induced by the mixed valence (3 + –4 + ) of the Mn ions. In particular, they exhibit very large negative magnetoresistance, called colossal magnetor…
Abstract In this article, the kinetics of thermal decomposition of unsaturated maleic–phthalic polyester resins, flame‐retarded with zinc hydroxystannate, was studied by thermogravimetric analysis at different heating rates. At the first stage, it was found, on the basis of isoconversional analysis by the methods of F…