Materials Literature
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An extended x-ray absorption fine structure technique has been employed to probe the average local structure around Mn impurity atoms in (In,Mn)As thin films prepared by organometallic vapor phase epitaxy. These films show ferromagnetism above room temperature. As the concentration of Mn increases, the average local e…
〈112〉 grain-oriented 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–0.3PT) piezoelectric ceramics with a degree of orientation of 0.35 have been produced from melt by a directional solidification method. The dielectric, ferroelectric, and piezoelectric properties were investigated, e.g., εrt∼4800, tan δ<0.6%, d33∼1500–1600…
Phonon heat transport based on the Boltzmann transport equation (BTE) in a free standing, bent duct with characteristic dimension down to the nanoscale is investigated through the lattice Boltzmann (LB) method. Both the thermal excited transverse and longitudinal phonons are considered. The collision term in BTE is ap…
The electrical conductivity of mesoscopic cubic cerium oxide crystals with space charge layers along their external boundaries has been calculated as a function of grain size. The equilibrium distribution of electronic and ionic charge carriers in this mixed conductor were obtained by numerical solution of the three-d…
Structure, magnetic, and transport properties of the compounds Bi0.5Ca0.5Mn1−xCrxO3 (BCMCO) with 0⩽x⩽0.15 have been experimentally investigated. The substitution of Cr3+ ion for Mn3+ ion suppresses the charge-ordering (CO) state obviously, leading to a gradual reduction of the CO transition temperature (TCO). In contr…
To assess the relevance of current crowding to electromigration-induced mass transport, a test structure was designed to structurally induce and accelerate current crowding in Cu damascene lines. Electromigration experiments and quantitative finite element analysis demonstrate how current crowding can substantially en…
We report the subthreshold characteristics of ballistic carbon nanotube field effect transistors (CNTFETs) showing the complex band structure effect. The tunneling of carriers from source to drain through a looped complex band structure increases the subthreshold drain current, reducing the on–off current ratio. We fi…
The polarized Raman spectra of a series of isostructural vanadate/phosphate compounds of the form: Tb(V1−xPx)O4 with 0⩽x⩽0.75 have been investigated at room temperature. While the observed Raman spectra are generally consistent with group theory predictions for a body-centered tetragonal crystal structure (D4h19), due…
Molecular dynamics simulations show significant differences in the deformation mechanisms of nanocrystalline nickel with low- and high-angle boundaries. For the case studied with average grain size of 12 nm, low-angle boundaries present enhanced dislocation activity and reduced strength with respect to high-angle boun…
Phase diagrams of mixtures of colloidal hard spheres with hard discs are calculated by means of the free-volume theory. The free-volume fraction available to the discs is determined from scaled-particle theory. The calculations show that depletion induced phase separation should occur at low disc concentrations in sys…
In order to fabricate an electronic device, we have optimized growth conditions of VO2 films on amorphous SiO2/Si structure substrates by pulsed laser deposition. The phase of VO2 films observed consisted of multiphases such as VO2, V2O5, and V2O3. The correlation between phase changes and growth conditions of VO2 fil…
Improved sets of empirical interatomic potentials for silicon-fluorine and silicon-chlorine are presented. The Tersoff-Brenner potential form has been reparameterized using the density-functional theory (DFT) cluster calculations of Walch. Halogenated silicon cluster energetics computed with DFT are, on average, withi…
Anisotropic in-plane strain can be induced in (Pb,Sr)TiO3 (PST) thin film by using orthorhombic NdGaO3 (110) as a substrate. High-resolution x-ray diffraction was used to measure the strain of the PST thin film. A rocking curve with full width at half maximum of ∼0.04° illustrated that the film had nearly perfect sing…
Theoretical study of the optical diffraction properties of holographic polymer-dispersed liquid crystal (HPDLC)-based thick volume grating was presented. It is found that the HPDLC grating can selectively diffract the s-polarized light only, p-polarized light only, or both s and p beams by selecting suitable grating p…
Structure and magnetostriction of Dy0.7−xTbxPr0.3(Fe0.9B0.1)1.93 (0⩽x⩽0.70) alloys have been studied. The easy magnetization direction of the Laves phase in the Dy0.7−xTbxPr0.3(Fe0.9B0.1)1.93 alloys with 0⩽x<0.20 lies along 〈100〉 axis, while that of the Laves phase in those alloys with 0.25⩽x⩽0.70 lies along 〈1…
The switching kinetics in fatigued polycrystalline bulk ferroelectrics do not exhibit relaxation with a singular time constant but rather stretched exponential behavior. Several microscopic mechanisms are discussed to explain this effect for a polycrystalline material. Some of the mechanisms may apply equally well to…
Pt /( Ba 0.7 Sr 0.3 ) TiO 3 (BST)/YBa2Cu3O7−x capacitors were prepared and investigated for the dead-layer (DL) thickness (td) and the DL dielectric constant (εd). Based on the series capacitor model, the td/εd ratio of 0.066 nm and the bulk BST ferroelectric-layer dielectric constant of 1370 were obtained through the…
Reactions of free silver anions Agn- (n = 1 - 13) with O2, CO, and their mixtures are investigated in a temperature controlled radio frequency ion trap setup. Cluster anions Agn- (n = 1 - 11) readily react with molecular oxygen to yield AgnOm- (m = 2, 4, or 6) oxide products. In contrast, no reaction of the silver clu…
A novel lambda-integration path is proposed for calculating the Gibbs free energy difference between any arbitrary solid and liquid state needed for the location of melting lines. This technique involves reversibly forcing a liquid state to a solid state across the phase transition along a nonphysical path, thermodyna…
ZnO nanorods were synthesized on sapphire (112̄0) substrates by metalorganic vapor deposition. The rods exhibited better crystalline and optical properties than those of ZnO rods formed on sapphire (0001) substrates. The emission due to biexcitons is persistent up to ∼200 K, indicating potential for applications in bi…