The influence of uniaxial compressive stress, T3, applied parallel to the electrical field, on the electromechanical parameters of 0.9Pb(Mg1/3Nb2/3)O3−0.1PbTiO3 ceramics in the dc electrical field-biased state and at temperatures near the dielectric constant maximum Tm was investigated. It was found that T3 reduces both the dielectric constant and polarization level, which results in a reduction of the piezoelectric coefficient with stress. However, the compliance of the material does not show much change with stress. As a consequence, the coupling factor k33 is also reduced with stress. On the other hand, the existence of the local micropolar region in the material causes anomalous changes in the aforementioned properties when the material is subjected to a high electric field, which induces a macropolar state. The transformation of this macropolar state back to a micropolar state under stress involves a large volume strain and results in an enhancement of the hydrostatic piezoelectric response.

Doped ceria, which has a higher oxygen ion conductivity than yttria-stabilized zirconia, is one of the possible electrolytes for solid oxide fuel cell at low temperatures. This study concerns powder preparation and densification of rare-earth-doped ceria. Rare-earth-doped ceria powders with a composition of Ce0.8R0.2O1.9 (R = Yb, Y, Gd, Sm, Nd, and La) were prepared by heating the oxalate coprecipitate when a mixed rare earth/cerium nitrate solution was added to an oxalic solution. The oxalate and derived-oxide powders were characterized by x-ray diffraction (XRD), thermogravimetry differential thermal analysis (TG-DTA), particle size analyzer with laser diffraction, inductively coupled plasma (ICP), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). This method provided the oxalate solid solutions containing Ce and R, which were calcined to form the oxide solid solutions at 600 °C in air. The lattice parameter of oxide powders increased linearly with increasing ionic radius of doped rare earth. The size of platelike particles of oxalates and oxides depended on the concentration of oxalic acid and showed a minimum at 0.4 M oxalic acid. Dry milling of oxide powder with α–Al2O3 ball was effective in reducing the size and aspect ratios of particles with little contamination of Al2O3. These rare-earth-doped ceria powders with various sizes were formed by uniaxial pressing (49 MPa) followed by cold isostatic pressing (294 MPa), and sintered at 900–1600 °C in air for 4 h. The micrometer-sized-doped CeO2 powders were densified above 95% of the theoretical density at 1200 °C. The grain size of rare-earth-doped ceria after sintering at 1600 °C was larger in the samples with the larger rare-earth element.

Vacuum depositions of Au on highly oriented pyrolytic graphite (HOPG) and SiO2 substrates in iodine vapor of 1 × 10–4 Torr give rise to formation of dispersed nanoscale Au particles at room temperature. The iodine is physisorbed on the Au surface and prevents the Au particles from coalescing. The mean diameter of Au particles on highly oriented pyrolytic graphite (HOPG) is about 40 nm, which is larger than that on SiO2 The particles on HOPG have a narrower and more uniform size distribution than those on SiO2. Radial distribution function of the particles on HOPG showed many well-defined peaks, whereas that on SiO2 had only one peak, indicating highly structured deposition on HOPG by iodine adsorption.

For the metalorganic chemical vapor deposition (MOCVD) of copper, (hfac)Cu(VTMS) (hfac = hexafluoroacetylacetonate, VTMS = vinyltrimethylsilane) and (hfac)Cu(ATMS) (ATMS = allyltrimethylsilane) were compared, and the effect of L ligand in (hfac)Cu–L was examined. It was found by 1H-NMR (nuclear magnetic resonance) that the thermal stability of (hfac)Cu(VTMS) was better than that of (hfac)Cu(ATMS) due to the relatively weak Cu–ATMS bond. From in situ Fourier transform infrared spectroscopy (FTIR) experiments, the formation of Cu(hfac)2, the product of disproportion reaction of Cu(hfac), was observed in the gas phase and (hfac)Cu(ATMS) was found to be more reactive to form Cu(hfac)2. The minimum temperature for the deposition of copper films from (hfac)Cu(ATMS) was as low as 60 °C, which was about 70 °C lower than from (hfac)Cu(VTMS). The grain size of the film deposited with (hfac)Cu(ATMS) was substantially larger than that with (hfac)Cu(VTMS), which showed that the chemical reactivity of the precursor had an influence on the microstructure along with the deposition temperature.

In order to investigate the absolute value for the total and exchange-correlation energies of small transition metal clusters, an all-electron mixed-basis approach with the generalized gradient approximation (Perdew–Wang's GGA-1) is applied for the first time to small Cu clusters. We find that the GGA significantly deepens (2.57–2.59 a.u. per atom) both the total and exchange-correlation energies obtained with the local density approximation. A better agreement is obtained with experiments for the binding energy of Cu2 when the spin-dependent calculation is used for an isolated Cu atom.

The interdiffusion in Ni80Fe20/Mo magnetic multilayers with a repeat length of 3.4 nm has been investigated using x-ray diffraction (XRD) technology. The multilayers have been fabricated by using a magnetron sputtering system. The decay with annealing time in the intensity of the first-order x-ray satellite peak arising from the composition modulation was used to determine the effective interdiffusion coefficient Dλ. As the annealing temperature is below 483 K, the interdiffusion is found to be relatively slow (Dλ < 8.88 × 10−25 m2/s). This result suggests that the Ni80Fe20/Mo multilayers have a strong resistance to the atomic interdiffusion between sublayers. The diffusivities over the temperature range 343–683 K have an Arrhenius-type temperature dependence with a pre-exponential factor D0 = (4.02 ± 1.21) × 10−22 m2/s and an activation enthalpy of about 0.26 ± 0.08 eV. The much lower activation enthalpy is attributed to the coherence strains existing in the multilayers.

Formation of silicon oxide thin films from spin-coated β-chloroethyl silsesquioxane (β-cesq) on silicon, NaCl, and quartz was induced by 193 nm laser pulses. The silicon oxide deposition is characterized by ir, uv, ellipsometry, and Rutherford backscattering spectrometry. The silicon oxide films obtained by uv irradiation were found to have much less carbon and chlorine as impurities and have a higher refractive index as compared to those obtained by annealing. The photoinduced oxide films were found to be smooth, without laser-induced microrough or periodic structures.

Amorphous fluorinated silicon nitride films have been deposited with the variation of NF3 flow rate using SiH4, N2, Ar, and NF3 gases by inductively coupled plasma enhanced chemical vapor deposition for the first time, and the absolute composition, oxidation mechanism, and optical properties were investigated. The absolute composition including hydrogen was performed by means of elastic recoil detection time of flight. It was found that the oxygen and fluorine contents in the film dramatically increased, but the hydrogen content decreased to below 4 at.% as the NF3 flow rate increased. The oxidation mechanism could be explained in terms of the incorporation of the activated residual oxygen species in the chamber into the film with unstable open structure by the fluorine-added plasma. It was shown that the density and optical properties such as refractive index, absorption coefficient, and optical energy gap depended on the film composition. The variations of the above properties for fluorinated silicon nitride film could be interpreted by the contents of fluorine and oxygen with high electronegativity.

An attempt has been made to interpret the experimentally reported transitions of layer sequences during the Co/Si, Ti/Si, and Ni/Si interfacial reactions in a consistent way, and to build a thermodynamic calculation scheme that enables it. The basic ideas are that the silicide with the highest driving force of formation under a metastable local equilibrium state at an interface would form first at the lowest temperature, and that when several silicides can nucleate simultaneously and compete for growth at an initial stage of a high temperature reaction, the one whose composition is closest to those of surrounding phases would form a continuous interfacial layer first and grow thicker. A critical review of literature information has also been made in order to clarify the first-forming silicide and silicide formation sequence in each metalySi interfacial reaction. The observed first-forming crystalline silicides, CoSi, Ti5Si3, and Ni2Si, in each metalySi interfacial reaction were in agreement with the present prediction based on the first idea. The reason why Co2Si and C49 TiSi2 have frequently been observed in high temperature Co/Si and TiySi reactions as if they were the first-forming crystalline silicides could also be explained based on the second idea. By combining both ideas, a general thermodynamic calculation scheme that can be applied for analysis, rationalization, and even prediction of interfacial reactions between different materials could be suggested.

We have investigated the effect of RuO2 (10, 30, 50 nm)/Pt layered hybrid bottom electrode structure and film composition on the leakage and fatigue properties of chemical solution derived Pb(ZrxTi1−x)O3 (PZT) thin films. It was observed that the use of high Ti content (Zr: Ti = 30: 70) films with control of excess PbO at the thin RuO2 (10 nm)/Pt bottom electrode surface reduced leakage current and showed good fatigue properties with high remanent polarization compared to the use of high Zr films (Zr: Ti = 50: 50) or thicker RuO2 (30, 50 nm)/Pt bottom electrodes. Typical P-E hysteresis behavior of PZT films was observed even at an applied voltage of 3 V, demonstrating greatly improved remanence and coercivity. Fatigue and breakdown characteristics of these modified PZT thin films (Zr: Ti = 30: 70) on RuO2 (10 nm)/Pt, measured at 5 V, showed stable behavior, and less than 15% fatigue degradation was observed up to 1010 cycles.

Polycrystalline SrBi2Nb2O9-layered ferroelectric thin films were synthesized on Pt/Ti/SiO2/Si substrate using the polymeric precursors solution. The dip-coated films were specular and crack-free and crystallized during firing at 700 °C. Single-, double-, and triple-layered films were obtained by several dips in the deposition solution, and the influence of crystallization between each dip was studied. Microstructure and morphological evaluation were followed by grazing incident x-ray diffraction (GIXRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Multilayered films obtained using the intermediate-crystallized layer route present a dense microstructure with spherical grains, with a preferential orientation in the 〈215〉 direction; films obtained using the intermediate-amorphous layer route are polycrystalline and present elongated grains around 250 nm in size.

Single Ti layers, single TiN layers, and thin Ti films overlayered with Au were investigated as ohmic contacts to n-type (n 4.5 × 1017 to 7.4 × 1018 cm−3) single-crystal GaN (0001) films. Transmission line measurements (TLM) revealed the as-deposited TiN and Au/Ti contacts on n = 1.2 − 1018 cm−3 to be ohmic with room-temperature specific contact resistivities of 650 and 2.5 × 107minus;5 Ω cm2, respectively. Single Ti layer contacts had high resistance and were weakly rectifying in the as-deposited condition. The three contact/GaN systems exhibited a substantial decrease in resistivity after annealing; the value of ρc was also a function of the carrier concentration in the GaN. The Au/Ti contacts exhibited the lowest resistivity values yet observed in these contact studies, particularly for the more lightly doped n-GaN. The ρc for n = 1.2 × 1018 cm−3 reached 1.2 × 1026 Ω cm2; for n = 4.5 × 1017 cm−3, ρc = 7.5 × 1025 Ω cm2 after annealing both samples through 900 °C. X-ray photoelectron spectroscopy (XPS) and high-resolution cross-sectional transmission electron microscopy (X-TEM) analysis revealed the formation of TiN at the interface of annealed Ti layers in contact with GaN, which is believed to be beneficial for ohmic contact performance on n-GaN.

Both epitaxial and crystallographically fiber-textured ZnO films can exhibit a surface texturing (“cratered”) morphology when grown by pulsed laser deposition at temperatures in the range of 350–750 °C in a background pressure of oxygen. The surface texturing is a consequence of the nucleation of oriented c axis grains that grow geometrically and impinge laterally. It is concluded that the surface texturing is due to nonequilibrium growth, being the result of a competition between the arriving flux, diffusive flux along the surface, and, possibly, concurrent ion etching from the laser-ablated plasma plume. At higher temperatures, no surface texturing occurs, presumably because of concurrent grain growth and more rapid surface smoothing by diffusion.

Intrinsic stresses which arise during the chemical vapor deposition (CVD) of diamond were controlled by multistep processing. Film stresses (thermal and intrinsic) were measured with the bending plate method. The thermal stresses are compressive and arise due to the mismatch in thermal expansion coefficient between the film and substrate. The dominant intrinsic stresses are tensile and evolve during the deposition process. These stresses increase with deposition time. An intermediate step consisting of annealing the film when the diamond crystallites are only partially coalesced reduces the intrinsic stress by more than 50%. Annealing at longer growth times (i.e., after complete coalescence) does not produce large reductions in intrinsic stress. Our results are consistent with stress generation due to the formation of nonequilibrium grain boundary structures. The intermediate annealing step does not produce a large, direct stress reduction; instead, it alters the film microstructure in some subtle way which reduces stress generation during subsequent growth.

Diamondlike carbon (DLC) films have been prepared on radio-frequency (rf) biased substrates maintained at low temperature using electron cyclotron resonance CH4–Ar plasma. The effects of negative rf bias and reactant gas composition on the bonding structure, hardness, and resistivity of the films were systematically investigated. DLC films deposited on PMMA (polymethyl methacrylate) were examined by optical methods to determine the absorption coefficients and the optical band gap. It was found that DLC films synthesized at bias voltage of 2(80–100) V and FCH4/FAr of 0.075–0.086 exhibit extreme hardness of more than 3000 kgf mm−2, high electrical resistivity up to 1014 Ω cm, band gap larger than 2.5 eV, and excellent optical transparency. The results indicate that ECR CH4–Ar plasma with low negative rf bias and suitable CH4/Ar gas ratio can process optically transparent and hard protective DLC films on PMMA plastics.

The shear viscosity of borosilicate glass (BSG) + silica powder compacts was determined during isothermal sintering at temperatures between 665 and 715°C. An optical system was used to measure in situ the densification profiles of the compacts in the form of thick films constrained on a rigid substrate and in-plane stresses generated during sintering. The shear viscosity as a function of relative density was calculated from these measurements by using Scherer's viscous constitutive equations for a porous sintering body. The shear viscosity for samples with silica contents from 0 to 20 vol% generally showed a slow increase with density in the low-density regime followed by a rapid rise after some threshold density that decreased with either increasing silica powder content or decreasing sintering temperature. The dependence of shear viscosity on relative density is consistent with results from sinter-forging experiments. However, results obtained from pure BSG compacts also revealed strong dependence of shear viscosity on temperature and microstructure, which has been all but neglected in previous theoretical studies.

Glasses in the NiO–TiO2 system in the composition range 15 to 25 mol% of NiO have been synthesized by the sol-gel technique by heat treatment of the precursor sol at 500°C. The glass structure is built up by crosslinking of two units, namely TiO6 octahedron and NiO3 triangle. Glassy structure is confirmed at a microscopic level by scanning electron microscopy. An increase in the values of peak-to-peak width of electron paramagnetic resonance with increasing concentration of Ni2+ is attributed to an enhanced interaction between neighboring paramagnetic Ni2+ ions.

The third-order nonlinear optical susceptibilities, χ(3), of the xLi(Na and K)2O · (100 − x)TeO2 binary glasses have been measured by the third harmonic generation (THG) method. It is found that the χ(3) of each series of glasses decreases with increasing alkali oxide content. The largest χ(3) values obtained are about 1.3 × 10−12 esu for a 7.5Li2O · 92.5TeO2 glass, being about 45 times larger than that of fused silica glass for the present series samples. For the purpose of investigating the relationship between the χ(3) and the optical parameters, such as linear refractive index, polarizability per unit volume which is represented by the term (nω2 – 1)/(nω2 + 2), dispersion energy (Ed) which is related to the Abbé number, and excitation energy (E0) which is closely related to the optical band gap (Eg), we derived the equations that relate the χ(3) to optical parameters on the basis of Lines’ model. Finally, it was experimentally confirmed that the χ(3) value of alkali oxide-TeO2 glasses is proportional to the term (nω2 + 2)3 (nω2 – 1) · Ed/E02

In this paper, we report atomic force microscopy (AFM) images of a tubular polymer and its supermolecular polymer thin films, operated in contact mode at room temperature in air. The configuration models are also calculated using molecular dynamics. The diameter of the polymer nanotube is about 0.7 nm, the smallest size a tube can have. The results of calculation agree with the experimental results.

The optical properties of heat-treated polyparaphenylene (PPP) were investigated by means of Raman and photoluminescence (PL) spectroscopy. Special attention is given to PPP heat-treated to temperatures (THT) near the carbonizing temperature region (THT ≈ 700°C) since polymer-based carbonaceous compounds with low-THT (<1000 °C) have been found to exhibit electrochemical properties that strongly contrast both the as-prepared polymer and fully carbonized samples. The Raman spectra show that for THT in the range 650–725°C, several Raman bands near 1300 cm−1 can be correlated with both ground-state benzenoid and excited-state quinoid PPP Ag modes. An increase in quinoid character is observed with increasing THT, which is consistent with the theoretically predicted stabilization of the quinoid form in the presence of a high density of defects. The smaller energy bandgap for π – π* transitions in the quinoid conformation relative to that for the benzenoid form allows for a resonance condition to be present for laser excitation wavelengths (λexc) near the visible (∼1–2 eV). We also report a small dispersion effect in the observed quinoid breathing mode band which can be compared to dispersion effects previously reported for the case of trans-PA. The decrease in bandgap for the defect-induced quinoid form is also evidenced in the PL spectra of samples heat-treated up to 650°C, which show vibronic structure in the blue-green emission data in the energy range 2.4–3.0 eV, with well-resolved peaks separated by quinoid phonon energies of 0.165 eV. Franck–Condon analysis shows an increase in the Huang–Rhys parameter (S) with increasing THT which can be related to changes in the electron-phonon coupling of valence and conduction band states.