Materials Literature
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Room-temperature micro-Raman scattering and temperature-dependent dielectric measurements were carried out on sol-gel-derived ferroelectric Pb1−xLaxTi1−x/4O3 (PLT x=0.05–0.30) thin films. Results indicate that the crystal structure and the electrical properties of PLT films were strongly influenced by the La contents.…
Two novel disc-shaped compounds (1, 2) with strong intramolecular hydrogen bonds were prepared and characterized; compound 2 showed a thermotropic mesophase as characterised by polarized optical microscopy, DSC and X-ray diffraction studies.
We performed piezoelectric force microscopy (PFM) measurements on arrays of poled nanosize domains in 150 nm thick 〈111〉 preferentially oriented Pb(Zr0.4Ti0.6)O3 films grown by chemical solution deposition. Each domain of arrays was characterized by dot, egg, and ring structures depending on the pulse width ranging fr…
To study the ion dynamics in an amorphous mixed alkali system, frequency-dependent conductivities of 0.3[xLi2O·(1 − x)Na2O]·0.7B2O3 glasses have been measured by impedance spectroscopy in a wide temperature range. The conductivities show a transition from their dc values into a dispersive regime where they increase co…
The phase transition behaviour and equilibrium phase relations in the fast-ion conductor system Na3PO4–Na2SO4 have been investigated using a combination of insitu XRD, neutron powder diffraction, and molecular dynamics simulation. The simulations predict that tetrahedrally-coordinated Na is relatively tightly bound wi…
Ground state ring opening/closing reactions of 1,3,3-trimethylspiro[indoline-2,3′-naphtho[2,1-b][1,4]oxazine] have been studied using DFT calculations. An extensive description of the ground state ring opening/closing and isomerization processes undergone by the eight open forms is proposed. The pathways for ring open…
With the help of spectroscopic data, we have characterized several isolated entities resulting from the reaction of lanthanide ions with a hexadentate Schiff base ligand obtained by reacting o-vanillin and 1,2-diaminoethane. This H2L ligand possesses two coordination sites, an N2O2 inner site and an O2O2 outer site. I…
We have used the lattice-mismatch epitaxial strain, induced by the constraint of epitaxy, to tune the metal–insulator (M–I) transition temperature of NdNiO3 films grown on Si(100) substrate. Films were integrated with the Si(100) substrate using several combinations of thin buffer layers. A systematic variation in the…
The dissipative particle dynamics technique has been used to study grafted polymer chains under shear in solvents of different quality. We show that width of the grafted polymer chains decreases with increasing shear rate for an adsorbed monolayer and bilayer in an athermal solvent but that the layer shrinks in a poor…
Bi-excess SrBi2Ta2O9 (SBT) thin films on Pt/Ti/SiO2/Si substrate were prepared by pulsed laser deposition technique. The SBT structure was characterized by x-ray diffraction studies. The ferroelectric properties were confirmed by P–E hysteresis loops at different applied electric fields. The dielectric constant and th…
ZnSe nanoparticles were synthesized by reacting vapors of (CH3)2Zn:N(C2H5)3 and H2Se, diluted in H2, in an opposed flow reactor operating at room temperature and 120 Torr. The particles were collected as random aggregates on silicon substrates and transmission electron microscopy (TEM) grids placed downstream of the r…
LaTiO x films have been grown on (001) perovskite oxide substrates by pulsed-laser deposition. Both single-phase perovskite LaTiO3 and layered La2Ti2O7 films could be stabilized by varying the oxygen partial pressure and substrate temperature during growth. We have obtained a crystallographic and electronic phase diag…
We have fabricated fully vacuum-sealed 5 in. diagonal carbon nanotube field-emission displays of a gated structure with reliable electron emission characteristics. Single-walled carbon nanotube tips were implemented into the gate structure using self-aligned backside exposure of photosensitive carbon nanotube paste. A…
Pulse-current electrochemical deposition has been used to prepare Ni nanoparticles that are used as the catalysts for the growth of aligned carbon nanotubes. The nucleation site density of the Ni nanoparticles was controlled by changing the magnitude and duration of the pulse current. The aligned carbon nanotubes from…
Using ammonia as nitrogen source for molecular beam epitaxy, the GaN-based diluted magnetic semiconductor Ga1-xMnxN is successfully grown with Mn concentration up to x~6.8% and with p-type conductivity. The films have wurtzite structure with substitutional Mn on Ga site in GaN. Magnetization measurements revealed that…
We calculate the tunneling splittings in a Mn$_{12}$ magnetic molecule taking into account its internal many-spin structure. We discuss the precision and reliability of these calculations and show that restricting the basis (limiting the number of excitations taken into account) may lead to significant error (orders o…
Considering the model heat conduction problem in the setting of Grad's moment equations, we demonstrate a crossover in the structure of minima of the entropy production within the boundary layer. Based on this observation, we formulate and compare variation principles for solving the problem of boundary conditions in…
Resistivity and thermoelectric power (TEP) measurements on CeFe$_2$ and two of its pseudo-binaries Ce(Fe, 5% Ir)$_2$ and Ce(Fe, 7% Ru)$_2$ between 78K and 275K are reported. The resistivity data are analysed in terms of contributions from scattering due to phonon, magnon, spin fluctuation and lattice defects, and also…
Correlated atomic-force and fluorescence microscopy are used to study single-particle versus ensemble fluorescence quantum yields (QY) of semiconductor nanocrystals by measuring a simultaneous map of the topography and the single-particle fluorescence. CdSe/ZnS nanocrystal quantum dots and quantum rods with high QY we…
GaMnN thin films were synthesized using gas-source molecular-beam epitaxy. Mn concentrations between 3 and 12 at. % were investigated. No evidence of second-phase formation was observed by powder x-ray diffraction or high-resolution cross section transmission electron microscopy in films with 9% or less Mn. The films…