Materials Literature
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Classical density-functional theory is employed to study finite-temperature trends in the relative stabilities of one-component quasicrystals interacting via effective metallic pair potentials derived from pseudopotential theory. Comparing the free energies of several periodic crystals and rational approximant models…
The temperature dependence of the critical scattering above and the order parameter below have been measured for sodium nitrate using time-of flight neutron diffraction. Sodium nitrate undergoes a structural phase transition from a low-temperature rhombohedral structure to a high-temperature structure which is charact…
A series of interstitial nitrides with has been prepared for R = Ce, Nd, Sm, Gd, Tb, Dy or Y. The nitrides have structures related to , but the unit-cell volumes are 4.7 - 6.6% greater and the magnetic ordering temperatures some 224 - 361 K higher than those of the parent compounds, and the saturation magnetizations a…
We report the successful deposition of highly c-axis oriented CaBi2Nb2O9 (CBN) thin films directly on p-type Si(100) substrates by pulsed laser deposition. The CBN thin films exhibited good structural, dielectric, and CBN/Si interface characteristics. The electrical measurements were conducted on CBN thin films in a m…
The low-temperature - high-temperature rhombohedral-ferroelectric phase transition and the rhombohedral-ferroelectric - cubic-paraelectric phase transition in Nb-doped ceramics (x = 0.05 and 0.25) were investigated using dielectric and resonance frequency measurements. The dielectric behaviour in PZT(Nb)95/5 is found…
Titanium hydride with a body centred tetragonal structure was rapidly synthesized at room temperature by ball milling titanium powders under a hydrogen atmosphere. The structure evolution was monitored by x-ray diffraction and Rietveld analysis. Unit cell volume dilation suggests the hydrogenation process begins with…
Using ${10}^{6}$-atom molecular-dynamics simulations, we investigate dynamic fracture in nanophase ${\mathrm{Si}}_{3}{\mathrm{N}}_{4}$. The simulations reveal that intercluster regions are amorphous, and they deflect cracks and give rise to local crack branching. As a result, the nanophase system is able to sustain an…
Crack propagation in a graphite sheet is investigated with million atom molecular-dynamics simulations based on Brenner's reactive empirical bond-order potential. For certain crystalline orientations, multiple crack branches with nearly equal spacing sprout as the crack tip reaches a critical speed of ${0.6V}_{R}$, wh…
The thermoluminescence (TL) of ZnS nanoparticles is reported. The TL intensity increases as the particle size is decreased. The consistency of the size dependence of the TL with that of the surface fluorescence indicates that the TL may be related to the surface states. TL may be caused by the recombination of carrier…
Laser scanning confocal microscopy has been used to study the time evolution of a three dimensional spatially bicontinuous structure of a phase-separated polymer blend undergoing the late stage of spinodal decomposition, as a model example of condensed matter systems. Both the mean and Gaussian curvatures of the inter…
The carrier transport in different phases of a new photoconductive calamitic liquid crystal, 2-(4\ensuremath{'}-heptyloxyphenyl)-6-dodecylthiobenzothiazole was studied by the time-of-flight technique: In the smectic A phase, a fast hole transient photocurrent was obtained in a nondispersive manner, in which the mobili…
The vacancy in diamond is a fundamental defect which has been studied theoretically and experimentally for forty years. However, although early theories (Coulson C A and Kearsley M J 1957 Proc. R. Soc. A 241 433) were extremely successful in explaining the nature of the ground state of the neutral defect and the Jahn…
We propose that extended orientational correlations can appear at the surface of supercooled heavy noble liquid metals, due to the same compressive forces that cause reconstruction of their crystal surfaces. Simulations for liquid Au show a packed surface layer structurally akin to a defected 2D triangular solid. Upon…
A new kind of scaling analysis for the conductivity spectra of glasses without any arbitrary parameters is presented. By applying this method to sodium borate glasses of different compositions, we find strong indications for the existence of a universal ionic relaxation process as well as for a strong electrolyte beha…
Carbon nanotube sheet electrodes have been prepared from catalytically grown carbon nanotubes of high purity and narrow diameter distribution, centered around 80 Å. Our study shows that the electrodes are free-standing mats of entangled nanotubes with an open porous structure almost impossible to obtain with activated…
Structural changes of the intermetallic compound SmCo5 after hydrogenation and nitrogenation were investigated by x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Amorphization was not observed by hydrogenation of SmCo5. On the contrary, an amorphous a-SmCo5N1.2 alloy was syn…
The sandwich-like title complex, hexakis(dimethylformamide)-1κO,2κO,3κO,4κO,5κO,6κO–bis[2,4,6,8,10,12-hexaphenylsiloxane-2,4,6,8,10,12-hexaolato(6−)-1:2κ2O1,2:3κ2O2,3:4κ2O3,- 4:5κ2O4,5:6κ2O5,1:6κ2O6]hexacopper(II) tetrakis(dimethylformamide) solvate, [Cu6(C3H7NO)6{(C6H5)6O12Si6}2].4C3H7NO, is comprised of two regular…
We studied the energy transfer between excitons and the 3d electrons of ${\mathrm{Mn}}^{2+}$ in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$ Te crystals within a Mn concentration range of 0.2\ensuremath{\leqslant}x\ensuremath{\leqslant}0.45 at T=2, 5, and 20 K by emission, excitati…
Spin-resolved photoemission spectra of 6-, 9-, and 13-eV satellites of the ferromagnetic Ni valence band are reported. The spin polarization of the valence-band satellites and their photon energy dependence are interpreted by the multiplet configuration of ${3\mathrm{d}}^{8}$ and ${3\mathrm{d}}^{7}$ final states. This…
The title compound, lead(II)dodecabismuth(III) pentamolybdenum(VI) oxide, was prepared by solid-state methods. The structure consists of (Bi12O14)8n+n columns surrounded by (MoO4)2− tetrahedra. The Pb atoms occupy specific sites between four tetrahedra.