Materials Literature
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Contrary to conventional wisdom, mineralization is not the only strategy evolved for the formation of hard, stiff materials. Indeed, the sclerotized mouthparts of marine invertebrates exhibit Young's modulus and hardness approaching 10 and 1 GPa, respectively, with little to no help from mineralization. Based on bioch…
This study reports a high‐energy density piezoelectric polycrystalline ceramic composition in the system Pb(Zr 1− x Ti x )O 3 –Pb[(Zn 1− y Ni y ) 1/3 Nb 2/3 ]O 3 (PZT–PZNN). Two different Zr/Ti ratios in the PZT system were investigated: 52/48 corresponding to morphotropic phase boundary (MPB) and 56/44 corresponding…
In this paper we have developed a theory of energetics for isolated single-wall carbon nanotubes (SWNTs) deformed in the radial direction, and applied this theory to investigate their deformation characteristics and stability under hydrostatic pressure. The starting point of the theory is the strain energy of SWNTs pr…
For the first time, explicit, analytical expressions have been derived for the dependence of electrical conductivity, chemical expansion, and elastic modulus on defect concentration and oxygen partial pressure using a consistent approach. The models have been validated with experimental data for Ce 0.9 Gd 0.1 O 1.95−δ…
Mimicking sponges: Well-defined crystalline nanoparticles of cubic BaTiO3 are prepared at a very low temperature by using a bio-inspired methodology. A bimetallic alkoxide is used as a single-source precursor in a vapor-diffusion sol–gel synthesis. Water and catalyst (HCl) are delivered in a spatial and temporal gradi…
Abstract Die Entwicklung von Hybridmaterialien mit stark verbesserten Funktionen gelingt durch die Kombination geeigneter Nanomaterialien als Träger mit Motiven aus der supramolekularen Chemie. Diese “hetero‐supramolekularen” Konzepte bieten vielfältige Möglichkeiten, die Lücken zwischen der Molekülchemie, Materialwis…
Single‐phase and lead‐free Bi 0.85 La 0.15 FeO 3 multiferroic ceramics were prepared by a rapid liquid sintering method to study their crystal structure and multiferroic behaviors. Rietveld refinement of X‐ray diffraction data showed a pseudo‐cubic structure plus a small triclinic distortion. The absence of Fe 2+ ions…
Ultra‐fine zirconium diboride (ZrB 2 ) powders have been synthesized using inorganic–organic hybrid precursors of zirconium oxychloride (ZrOCl 2 ·8H 2 O), boric acid, and phenolic resin as sources of zirconia, boron oxide, and carbon, respectively. The reactions were substantially completed at a relatively low tempera…
Highly porous alumina ceramics with completely interconnected pore channels were fabricated by freezing dilute alumina/camphene slurries with solid loadings ranging from 5 to 20 vol%. This method fundamentally made full use of the three‐dimensional camphene dendritic network for producing interconnected pore channels…
The role of Pr doping on double Schottky barrier formations at ZnO single grain boundaries was investigated by the combination of current-voltage measurements, atomic-resolution Z-contrast scanning transmission electron microscopy, and first-principles calculations. Although Pr segregated to the specific atomic site a…
On the basis of Ti‐vacancy defect compensation mode, high‐permittivity La‐ and Ce‐doped barium titanate ceramics (BLTC) with perovskite structure, i.e., (Ba 1− x La x )(Ti 1− x /4− y Ce y )O 3 , where x =0.01–0.05 and y =0.05, were prepared by conventional ceramic processing techniques. Dielectric characteristics, X‐r…
We present a theoretical many-body analysis of the electron-electron (e-e) inelastic damping rate $Γ$ of electron-like excitations in the Shockley surface state band of Ag(111). It takes into account ab-initio band structures for both bulk and surface states. $Γ$ is found to increase more rapidly as a function of surf…
We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor…
To date, optical orientation of free-carrier spins and spin currents have been achieved by circularly polarized light, while the linearly polarized light has been used for optical alignment of electron momenta. Here we show that, in low-dimensional structures, absorption of the linearly polarized light also leads to t…
High-quality and impurity-free magnetite surfaces with (sqrt2xsqrt2)R45o reconstruction have been obtained for the Fe3O4(001) epitaxial films deposited on Fe(001). Based on atomically resolved STM images for both negative and positive sample polarity and Density Functional Theory calculations, a model of the magnetite…
The oxidation behavior of zirconium diboride containing 30 vol% silicon carbide particulates was investigated under reducing conditions. A gas mixture of CO and ∼350 ppm CO 2 was used to produce an oxygen partial pressure of ∼10 −10 Pa at 1500°C. The kinetics of the growth of the reaction layer were examined for react…
Abstract A differential AC‐chip calorimeter capable of measuring the step in heat capacity at the glass transition in nanometer‐thin films is described. Because of the differential setup, pJ/K sensitivity is achieved. Heat capacity can be measured for sample masses below 1 ng in broad temperature range as needed for t…
We have calculated the interfacial free energy for the hard-sphere system, as a function of crystal interface orientation, using a method that examines the fluctuations in the height of the interface during molecular dynamics simulations. The approach is particularly sensitive for the anisotropy of the interfacial fre…
Graphene has an unusual low-energy band structure with four chiral bands and half-quantized and quantized Hall effects that have recently attracted theoretical and experimental attention. We study the Fermi energy and disorder dependence of its spin Hall conductivity sigma(xy)(SH). In the metallic regime we find that…
Abstract We present results of molecular dynamics simulations for free‐standing and supported thin films of a nonentangled polymer melt using a coarse‐grained (bead‐spring) model. Our discussion is mainly concerned with the equilibrium properties of the films above the critical temperature ( T c ) of mode‐coupling the…