Materials Literature
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High-energy (h$ν$ = 5.95 keV) synchrotron Photoemission spectroscopy (PES) is used to study bulk electronic structure of Na$_{0.35}$CoO$_{2}$.1.3H$_{2}$O, the layered superconductor. In contrast to 3-dimensional doped Co oxides, Co $\it{2p}$ core level spectra show well-separated Co$^{3+}$ and Co$^{4+}$ ions. Cluster…
We have studied the depth-dependent magnetic and structural properties of as-grown and optimally annealed ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ films using polarized neutron reflectometry. In addition to increasing the total magnetization, the annealing process was observed to produce a signif…
We present a theory of the collective orbital excitation termed orbital wave in perovskite titanates and vanadates with the triply degenerate ${t}_{2g}$ orbitals. The dispersion relations of the orbital waves for the orbital-ordered ${\mathrm{LaVO}}_{3},$ ${\mathrm{YVO}}_{3}$ and ${\mathrm{YTiO}}_{3}$ are examined in…
We have used scanning SQUID magnetometry to image vortices in ultra-thin [Ba$_{0.9}$Nd$_{0.1}$CuO$_{2+x}$]$_m$/[CaCuO$_2$]$_n$ (CBCO) high temperature superconductor samples, with as few as three superconducting CuO$_2$ planes. The Pearl lengths ($Λ= 2λ_{L}^2/d$, $λ_{L}$ the London penetration depth, $d$ the supercond…
Analytical Hartree-Fock gradients with respect to the cell parameter have been implemented in the electronic structure code CRYSTAL, for the case of three-dimensional periodicity. The code is based on Gaussian type orbitals, and the summation of the Coulomb energy is performed with the Ewald method. It is shown that a…
The kinetic behavior of a phase field model of electrochemistry is explored for advancing (electrodeposition) and receding (electrodissolution) conditions in one dimension. We previously described the equilibrium behavior of this model [J. E. Guyer, W. J. Boettinger, J. A. Warren, and G. B. McFadden, Phys. Rev. E 69,…
A diffuse interface (phase field) model for an electrochemical system is developed. We describe the minimal set of components needed to model an electrochemical interface and present a variational derivation of the governing equations. With a simple set of assumptions: mass and volume constraints, Poisson's equation,…
A family of red light-emitting star-shaped porphyrins with four monodisperse conjugated oligofluorene arms was prepared by using two key reactions: Lindsey condensation and Suzuki-Miyaura cross coupling reactions. All porphyrins exhibit high quantum yields (about 0.22) and good solubility in common organic solvents, a…
As a first step towards understanding the morphology of PdO crystals we performed a systematic full-potential density-functional theory study of all possible $(1\ifmmode\times\else\texttimes\fi{}1)$ terminations of the low-index surfaces of tetragonal PdO. Applying the concept of first-principles atomistic thermodynam…
Nanocrystalline SnO2 quantum dots were synthesized at room temperature by hydrolysis reaction of SnCl2. The addition of tetrabutyl ammonium hydroxide and the use of hydrothermal treatment enabled one to obtain tin dioxide colloidal suspensions with mean particle radii ranging from 1.5 to 4.3 nm. The photoluminescent p…
Bismuth ferrite is a magnetoelectric material, which simultaneously has polarization and spin orders. We have used electron spin resonance (ESR) as a local probe of the magnetic order in the magnetic-field range of 0--25 T, in the frequency domain of 115--360 GHz, and at a temperature of 4.2 K. The data reveal signifi…
In order to develop a yellow phosphor that emits efficiently under the 450–470 nm excitation range, we have synthesized a Eu2+-activated Sr3SiO5 yellow phosphor and attempted to develop white light-emitting diodes (LEDs) by combining them with a InGaN blue LED chip (460 nm). Two distinct emission bands from the InGaN-…
Nanoscale structural and mechanical characterization of the shell of a red abalone has been carried out. Cobble-like polygonal nanograins are basic building blocks that are used to construct individual aragonite platelets into a mother-of-pearl configuration known as nacre. The nanograin-structured aragonite platelets…
We have used a nonlithographic deposition process to form single polymeric nanowire chemical sensors. Oriented polyaniline nanowires, with diameters on the order of 100 nm, were deposited on gold electrodes. The devices showed a rapid and reversible resistance change upon exposure to NH 3 gas at concentrations as low…
Single-phased ferroelectromagnet BiFeO3 ceramics with high resistivity were synthesized by a rapid liquid phase sintering technique. Saturated ferroelectric hysteresis loops were observed at room temperature in the ceramics sintered at 880 °C for 450 s. The spontaneous polarization, remnant polarization, and the coerc…
Umicore IR Glass is a company specialising in the production of chalcogenide glasses and moulded optics. The standard glass compositions are GASIR1 (Ge<sub>22</sub>As<sub>20</sub>Se<sub>58</sub>) and GASIR2 (Ge<sub>20</sub>Sb<sub>15</sub>Se<sub>65</sub>). These materials are transparent in the 3-5 μm and 8-12 μm…
Ultrathin oxygenated amorphous CdTe (a-CdTe:O) films are prepared by rf sputtering of CdTe in a background of argon or argon/nitrogen/oxygen mixtures. Atomic force microscopy (AFM) is used to characterize the films and shows that they have an island structure typical of most sputtered thin films. However, when suffici…
The coating deposition on large optical components (diameter 350 mm) has required the development of new metrology tools at 1064 nm. To give realistic values of the optical performances, the whole surface of the component needs to be scanned. Our scatterometer (commercial system) has been upgraded to support large and…
Experimental and theoretical studies of a novel family of germanium-carbon clusters (Ge(n)C(m)) that were initiated with our earlier identification of the GeC(3)Ge cluster have now been extended to the GeC(7) and GeC(9) chains. The new clusters, which were formed by laser ablation and trapped in solid Ar at approximat…
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