bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compositional and Structural Properties of Sputtered Plzt Thin Films
Authors: Borrelli P.J. , Ballentine P.H. , Kadin A.M. 
Published: March 2011

AbstractThin films of lanthanum-modified lead zirconate-titanate (PLZT) were prepared by rf magnetron sputtering from a single oxide target onto a heated substrate. The target consisted of Pbl-xLaxZryTi1-yO3 with composition close to x=8% and y= 65%, either as a loose powder or a solid sintered disk. Under appropriate conditions, the desired perovskite phase formed in situ without any subsequent post-anneal. Film composition and structure were correlated with deposition parameters, including substrate temperature, target composition, gas pressures, and target aging. For deposition onto MgO or A12O3 crystalline substrates, perovskite PLZT films formed if there was sufficient Pb at the target surface, sufficient oxygen in the sputter gas (≈ 50%), and a substrate temperature >≈600°C. Target heating led to excessive Pb loss from the loose powder target; this was much less significant for the solid target. In addition, it was found that deposition onto an epitaxial perovskite substrate promoted formation of the perovskite phase, leading to an epitaxial film. A prototype ferroelectric capacitor was fabricated by depositing a conducting perovskite film (the high-Tc superconductor YBa2 Cu3O7 ) on a perovskite substrate, sputtering PLZT on top, with Ag for a top electrode. Measurements indicate a remanent polarization of 5 μC/cm2 and a coercive field of 900 V/cm.
Sol-Gel Pzt Films for Optical Waveguides
Authors: Swartz S.L. , Ramamurthi S.D. , Busch J. R. , Wood V.E. 
Published: March 2011

AbstractSol-gel processing is a candidate ferroelectric thin-film deposition method for electronic and electro-optic applications. At Battelle, sol-gel PbTiO3 and Pb(Zr,Ti)O3 films have been prepared on sapphire and single-crystal SrTiO3 substrates. Films deposited and annealed on sapphire substrates are crystalline with the perovksite structure and minimal crystallographic orientation, whereas films deposited on isostructural and lattice-matched SrTiO3 substrates exhibit a high degree of orientation. Guided-mode refractive index measurements were made using a single-prism method and film indices were computed. Refractive index values measured for PbTiO3 films (n = 2.58) and PZT films (n = 2.50) were slightly lower than values expected on the basis of bulk measurements. In double-prism experiments, optical wavcguiding was achieved over distances up to 10 mm in oriented PZT films on [100] SrTiO3substrates. Optical loss of 19 dB/cm was measured on one of these film samples. Such films, given requisite improvement in optical quality, may be suitable for useful optical waveguide devices. An approach is presented for the integration of ferroelectric waveguides onto silicon and/or GaAs substrates.
Applications of PZT and Related Thin Films in Piezoelectric Microsensors
Authors: Polla D. L. , Ye C. , Schiller P. , Tamagawa T. , Robbins W. P. , Glumac D. , Hsueh C.-C. 
Published: March 2011

AbstractFerroelectric thin films have been deposited on polycrystalline silicon micromechanical structures to form both physical microsensors and microactuator devices. These devices which include acoustic pressure sensors, infrared detectors, micropositioners, and stepper motors are based on either the piezoelectric or pyroelectric properties of sol-gel Pb(ZrxTi1-x)O3 or PbTiO3 deposited on surface-machined microelectromechanical structures. Several materials, micromachining, process integration, and performance issues are introduced in the description of these devices.
Photoelectric Properties of Undoped and Fe-Doped LiNbO3 Films Made by Sol-Gel Method
Authors: Cheng Chih-Hsing , Xu Yuhuan , Mackenzie John D. 
Published: March 2011

AbstractTransparent lithium niobate (LiNbO3) with thickness from 0.1 - 1.2 μm were made on silicon, fused silica, and sapphire substrates by the sol-gel processing. Alkoxide solutions were used as starting materials. X-ray diffraction has been used to confirm the crystallization of the films. Refractive index, dielectric and ferroelectric properties of LiNbO3 films were studied. Absorption spectra of films of LiNbO3 and LiNbO3 with doping of different amount of Fe (0.1 - 2.5mol%) were measured. Short-circuit photocurrent measurements revealed both transient and steady state components attributed to a pyroelectric effect and a bulk photovoltaic effect respectively. Epitaxial growth of LiNbO3 thin film on sapphire(012) substrate by sol-gel method was also obtained.
Pyroelectric Microsensors by Sol-Gel Derived PbTiO3 and La-PbTiO3 Thin Films
Authors: Ye Chian-Ping , Tamagawa Takashi , Lin Ya-Yun , Polla D. L. 
Published: March 2011

AbstractFerroelectric PbTiO3 and Lanthanum-modified PbTiO3 thin films have been deposited on different substrate surfaces by sol-gel processing. The ferroelectric, dielectric, and pyroelectric properties and their temperature dependences have been investigated. The sol-gel derived thin films were integrated onto a membrane structure fabricated by solid-state surface-micromachining technology. The performance of the resultant devices have been tested as an uncooled infrared detector. The high voltage responsivity and short rise time are attributed to the combination of the pyroelectric film, the underlying polycrystalline silicon layer, and the thermal design of the composite structure. The addition of Lanthanum with a molecular fraction of 3% and 5% has resulted in a lower dielectric loss and a reduced thermal noise.
Compositional Dependence of the Quantum Efficiency of the Transition at 1.3 μm of Praseodymium in Halide Glasses
Authors: Swartz A. , Elyamani A. , Pafchek R. , Snitzer E. , Sigel G. H. 
Published: March 2011

ABSTRACTAn improvement in the quantum efficiency of the 1.3 μm transition of Pr3+ has been acheived as a result of doping alternative halide glasses. An increase from 3.4% in ZBLAN [1] to 9.9% in a multicomponent halide glass is reported.
Enhancement of Optical Third Order Nonlinearity in Main-Chain Oriented Polythiophenes
Authors: Okawa Haruki , Wada Tatsuo , Sasabe Hiroyuki 
Published: March 2011

ABSTRACTThe third order nonlinear responses for soluble one-dimensional ϕ-conjugated polymers, poly(3-alkylthiophene)s were investigated. Uniaxial stretching of the polymer film was carried out to align the polymer backbone. The stretched film showed large dichroism and crystallinity. Third order nonlinear susceptibility, χ(3)1111 of the stretched film was determined by optical third harmonic generation. A large enhancement of χ(3) due to the main chain alignment was observed.
Laser-Induced Fluorescence in Doped Metal Oxide Planar Waveguides Deposited from Aqueous Solutions
Authors: Hess Nancy J. , Exarhos Gregory J. , Wood Susanne M. 
Published: March 2011

ABSTRACTAn aqueous route to the deposition of complex metal oxide films is based upon the complexation of the corresponding metal nitrate salts by glycine, followed by spin-casting the concentrated solution onto silica substrates. The presence of glycine serves to frustrate precipitation and leads to the formation of a glassy matrix through which metal cations are homogeneously dispersed. Subsequent heating of coated substrates initiates an oxidation-reduction reaction which removes the organic matrix and residual nitrate leaving behind a film of the desired oxide composition. Using this method, ruby (Cr:Al2O3) and Sm:YAG (Sm:Y3Al5O12) films on the order of 150 nm thick have been deposited. The respective phases have been confirmed by XRD data and from the measured fluorescence spectra.The red fluorescence exhibited by these materials under 488 nm excitation is dependent upon the ambient temperature and pressure. A marked shift in wavelength is observed as a function of increasing pressure. Ruby also exhibits a temperature dependent wavelength shift in contrast to Sm:YAG where a negligible shift is seen to temperatures near 1200 K. Fluorescence lifetimes of both materials exhibit a temperature dependence which varies with dopant concentration. This work suggests the possible application of these films as pressure-temperature sensors in a planar waveguide configuration or as a coating material for optical fibers. Details of the deposition process will be reviewed and the fluorescence response of both types of films will be summarized.
Formation of Planar and Strip Waveguides in KNbO3 by He Ion Implantation
Authors: Fluck D. , Fleuster M. , Irmscher R. , Günter P. , Buchal C H. 
Published: March 2011

ABSTRACTSingle crystals of KNbO3 have an excellent potential for integrated and nonlinear optical applications. MeV He ion implantation is a reliable technique for the formation of permanent optical waveguides in this material. We have fabricated planar and strip waveguides using He energies between 1 and 3.5 MeV and ion doses of 5 × 1013 to 1016 ions/cm2. Waveguides were analyzed at a wavelength of 514, 633 and 860 nm.
Permanent Photoinduced Refractive Index Changes in Rare Earth Doped Glasses
Authors: Williams Glen M. , Ruller Jacqueline A. , Friebele E. Joseph 
Published: March 2011

ABSTRACTPermanent refractive index gratings were holographically photowritten into rare earth doped glasses using the 488 rn line of a Ar Ion laser. The rare earths Pr3+, Tb3+, and Eu2+ were examined. Experiments were performed to elucidate the mechanism responsible for the photoinduced index change. A model is presented in which the index change is accomplished through photoionization of the rare earth dopant and subsequent trapping of the free carrier. The viability of these materials for use in optical fiber grating devices is discussed.
Mechanical Properties of SiO2vs. SiO2-TiO2Bulk Glasses and Fibers
Authors: Gulati Suresh T. 
Published: March 2011

ABSTRACTThe mechanical properties of silica and titania-doped silica glasses, in bulk and fiber forms, are presented. These include the elastic properties (E and ν), strength distribution (in tension and bending), fatigue behavior (dynamic and static loading) and fracture toughness. Following a brief review of above properties for fused silica and ULE™ glasses (Coming Codes 7940 and 7971), used primarily for space applications, the mechanical properties data for silica and titania-doped silica-clad optical fibers are presented. The enhancement of mechanical performance of titania-doped silica clad fiber is also discussed.The effect of titania doping on fundamental properties like stress-free activation energy, crack tip pH, and deformation mode of Si-O-Si bond is discussed. In addition, the crack velocity data obtained from DCDC specimens of homogeneous silica and titania-doped silica glasses are compared in an attempt to understand the role titania plays in improving the fatigue resistance of optical fibers.
Radiation Response of Pure Silica Core Optical Fibers. IV
Authors: Skutnik Bolesh , Henschel H. , KÖhn O. , Schmidt H. U. 
Published: March 2011

ABSTRACTThe radiation response of a series of optical fibers with pure silica cores, that differed as to residual hydroxide and chloride content and as to preform formation, have been measured after exposure to pulsed electron beam radiation to 10 krads [100 Gys]. The irradiations were carried out at both ambient temperature and at −50°C and with two different operating power levels at each temperature. The responses have been analyzed seeking to identify correlations between the differences in the residual chemical contents or preform formation and the observed differences in the initial response and the recovery behavior among the optical fibers in the series.
Influence of Residual Water on the Strength of Metal Coated Optical Fibers
Authors: Bubnov M. M. , Dianov E. M. , Semjonov S. L. 
Published: March 2011

ABSTRACTThe influence of residual moisture under a metal coating on strength and fatigue of silica optical fibers was investigated. It was shown that for the fabrication of metalcoated fibers with strength – 10 GPa and low static fatigue it is necessary that the water content in the atmosphere during the freezing process should be less than 40 ppm.
Alkali Activated Cementitious Materials: An Overview
Authors: Roy D. M. , Silsbee M. R. 
Published: March 2011

ABSTRACTAlkali-activated cementitious materials have considerable potential, with properties ranging from very high early strength to very high long term strength and low porosity. The role of alkalis in activating industrial by-products such as ground granulated (glassy) blast-furnace slag, ultra-fine silica fume or other by-product silicas, glassy fly ashes, and other amorphous materials is discussed. These by-product materials are activated by alkali additions which break the strong silicon oxygen bonds in the silicate or alumino-silicate network, accompanied by the formation of new reaction products. The role of the different components in multi-component activated cements on the reactivity and the nature of the resultant products is discussed. Characterization of starting materials and reaction products by XRD, SEM (including environmental SEM), chemical, and particle characterization techniques has been made. Additional results include investigation of pore solution chemistry as a function of time. Some inferences for long term durability are discussed.
Preparation and Hydration Kinetics of Pure CaAl2O4
Authors: Gulgun M. A. , Popoola O. O. , Nettleship I. , Kriven W. M. , Young J. F. 
Published: March 2011

ABSTRACTSingle phase, pure monocalcium aluminate (CaAl2O4) powders are chemically synthesized at temperatures as low as 900°C. The powders have a specific surface area of approximately 10 m2/g. The hydration kinetics of CaAl2O4 and the morphology of the hydrates are analyzed using electron microscopy techniques
Effect of Starting Materials on the Synthesis of Tobermorite
Authors: Sato Hiroyoshi , Grutzeck Michael 
Published: March 2011

ABSTRACTThe effect of starting materials on the synthesis of tobermorite was studied using29Si MAS and CPMAS NMR Spectroscopy. Three Q2 and one Q3 peak were identified during the crystallization of tobermorite from C-S-H. C-S-H, which had a Ca/Si ratio >1, crystallized readily because this C-S-H consists of dimer and short chains of silica tetrahedra. This occurred whenever quartz was used as a starting material. C-S-H, which had a Ca/Si ratio <1 was harder to crystallize because this C-S-H consists of long and cross-linked chains of tetrahedra. The latter was observed when amorphous silica was used as a starting material.
Experimental and Computer Simulation Results for the Electrical Conductivity of Portland Cement Paste
Authors: Christensen B.J. , Mason T.O. , Jennings H.M. , Bentz D.P. , Garboczi E.J. 
Published: March 2011

ABSTRACTThe electrical conductivity of portland cement paste is an important transport property, especially since, when properly normalized by the pore fluid conductivity, it is equivalent to the normalized ionic diffusivity of the material via the Nernst-Einstein relation. This paper presents experimental and computer simulation results for σ/σo, where σ is the conductivity of the bulk paste as determined from impedance spectroscopy, and σo is the conductivity of the pore solution. Comparison between simulation and experiment is carried out for an 0.5 water:cement ratio white cement paste as a function of capillary porosity. The quantitative agreement between theory and experiment is reasonable.
The Development of Microstructure in Calcium Sulphoaluminate Expansive Cement
Authors: Herrick John , Scrivener Karen L. , Pratt Peter L. 
Published: March 2011

ABSTRACTUsing backscattered electron images, it is shown that an expansive clinker is polymineralic in nature, with individual particles containing the constituents (lime, anhydrite and anhydrous calcium sulphoaluminate) to form ettringite on hydration. The hydration reaction with time of a simple paste of a mixture of this expansive clinker with Ordinary Portland Cement (OPC) has been monitored using backscattered electron images, and the formation of ettringite and a change in the morphology of the calcium hydroxide formed from the added free lime from the expansive clinker is observed. Thermal analysis studies on pastes of the pure expansive clinker have confirmed this apparent change in morphology.
SO3-Rich Portland Cements: Synthesis and Strength Development
Authors: Abdul-Maula S. , Odler I. 
Published: March 2011

ABSTRACTUp to 8 per cent of SO3 may be incorporated into the crystalline lattice of C2S if burned in the presence of CaSO4. C3S may be formed only in the presence of F-. Under these conditions up to 5 per cent of SO3 may be incorporated. In the presence of CaSO4 and CaF2 in the raw meal portland clinkers may be formed that contain simultaneously the phases C3S and C4A3S. Clinkers of this kind yield cements with favorable strength properties at “optimum gypsum” additions.
The Nature of the Concrete-Steel Rebar Interface in Plain and Silica Fume Concrete
Authors: Zayed Abla M. 
Published: March 2011

ABSTRACTIn this investigation the nature and morphology of the concrete-reinforcing steel interface is studied. The effect of the partial replacement of cement by silica fume on the interface microstructure was determined. The distribution profiles of percentage porosity, calcium hydroxide and unreacted cement from the interface towards the concrete bulk were measured using the scanning electron microscope operated in the back scattering mode. The findings indicate the similarities between the morphology of the concrete-steel interface and those reported earlier in the literature for the concrete-aggregate interface. Additions of silica fume resulted in a decrease of the interface porosity and calcium hydroxide content.
Statics of Phase Transformation in Ni-Al, Ni-Ti And Cu-Zn: a First Principles Study
Authors: Turchi P. E. A. , Sluiter M. 
Published: March 2011

AbstractWe show that the interplay between electronic structure properties, crystalline effects and local chemical order is quite distinct for Ni-Al, Ni-Ti and Cu-Zn, although they all exhibit a first order displacive transformation upon cooling from a high temperature partially ordered B2 phase. For this purpose, electronic structure and phase stability properties of these three alloys are investigated with a first principles approach. The study is based upon the Generalized Perturbation Method applied to the Korringa-Kohn-Rostoker multiple scattering description of the Coherent Potential Approximation, and temperature effects are taken into account within a generalized mean field approach.
Shape Memory Effect with Low MsThermoelastic thin Plate Martensite in an FE-33Ni-12CO-5Ti Alloy
Authors: Jian Li , Chou C. C. , Wayman C. M. 
Published: March 2011

AbstractAn Fe-33Ni-12Co-5Ti (wt.%) alloy was subjected to aging treatments to determine the effect of ausaging (at 700 °C for 5, 10 and 30 hr) on the martensitic transformation and shape memory effect. The Mstemperatures were determined by electrical resistance measurements and microstructures were examined by TEM. The shape memory was studied by bending specimens in liquid nitrogen and found to be associated with a low Msthermoelastic thin plate martensite.
Surface Energy and Microstructure
Authors: Kohn Robert V. , MÜtller Stefan 
Published: March 2011

AbstractBulk energy considerations can predict the gross features of microstructures observed in martensitic phase transitions, but not finer details such as the length scale on which twinning occurs. These are determined by surface energy. A standard approach is to minimize the sum of bulk and surface energy within the class of “twinned” configurations. This leads to the conclusion that the twin width w and the twin length L should satisfy w ∼L∼. While that seems to be the rule, a different structure is sometimes observed, for example in In-Tl and Cu-Al-Ni. It involves successive coarsening of the twins away from an austenite/twinned-martensite interface.We re-examine the minimization of bulk plus surface energy. Our analysis differs from prior ones in that it permits configurations which are not essentially “onedimensional” to compete in the minimization. We find that the global minimum of energy can be either “one-dimensional” or “branched,” depending on the relative values of the elastic moduli and surface energy density.
Anisotropy of Tensile Recovery Stress and Two Way Memory Effect of Cold Rolled Tini Sheet
Authors: Mulder J. H. , Thoma P. E. , Beyer J. 
Published: March 2011

AbstractThe texture of cold rolled and heat treated TiNi sheet has been measured and designated as {110}<110>p. The.anisotropy of the tensile recovery stress, the stress dependence of the transformation temperatures, and the development of the two-way memory effect during thermal fatigue have been measured. The resulting changes of texture after thermal fatigue are presented and explained. The observed effects are explained on the basis of the parent texture and the specific martensite variants which are formed according to the lattice correspondence between austenite and martensite.
A Martensite Peculiar to Thin Foils of a Ti50Ni49Fei Shape Memory Alloy
Authors: Tadaki Tsugio , Yamamoto Sukeyoshi , Shimizu Ken'ichi 
Published: March 2011

AbstractA peculiar martensite found in thin foils of a Ti5oNi49Fei shape memory alloy has been examined by transmission electron microscopy and electron diffraction, which was entirely different from the R phase and the B19' and B19 martensites widely known so far in the Ti-Ni based alloys. The thin foil martensite is monoclinic with a=0.700nm, b=0.994nm, c=0.632nm and γ =94.4°. The lattice correspondence between the B2 parent phase and the martensite is as follows: <210>B2→ <100>M, <230>B2→ <010>m, <002>B2→ <001>m. The formation conditions and atom positions in the unit cell of the thin foil martensite are discussed.
Review of Phonon Behavior and Microstructural Development Leading to Martensitic Transformations in NixAl(100-x)Alloys
Authors: Tanner L. E. , Shapiro S. M. , Schryvers D. , Noda Y. 
Published: March 2011

AbstractElastic and inelastic neutron-scattering and high-resolution electron-microscopy examinations of the β2 (B2) phase of NixAl(100-x)alloys show a direct relationship between the anomalous changes in lattice dynamical behavior and the evolution of static premartensitic structural configurations as the β2 cools toward its martensitic transformation temperature,Ms. The resulting microstructure is a fine-scale mosaic assembly of nonuniformly distorted and modulated domains, in which {110}<110> shear-plus-shuffle displacements give rise to the {110}B2 micromodulations of ∼1.3 nm wavelength. These displacements are derived from the unusually low energy of the Σ4<ζζ0>–TA2phonon mode and its anomalous temperaturedependent incomplete softening at ζ = 0 (viz., the elastic constantC) and at ζ ≈ 0.16. These inhomogeneously strained domains (ISDs) are believed to be centered on low strain-amplitude defects. They are viewed as strain embryos of the product 7M(5, 2) martensite but are generally too weak to act as potent nucleation centers. Similar ISD configurations develop at defects with higher strain amplitudes (e.g., dislocations, grain boundaries) and these are the most likely sites for heterogeneous nucleation to occur.
Coherent Nucleation and Growth of Marte1Nite in B2 Nial Oberved in Computer Simulations
Authors: Clapp P. C. , Shao Y. , Rifkin J. A. 
Published: March 2011

AbstractIn atomistic simulations of B2 NiAl usirn Molecular Dynamics and Emxbedded Atom Method Ni-Al potentials, both thermally induoed and stress induced crent martensitic nucleation and growth processes of a tetragonal Llo phase have been observed, including the formation of self-accommodating martensite variants. Nucleation is found to occur only at special heterogeneous sites that can be well characterised. Prior to nucleation, clear evidence of the buildup of large amplitude localized soft modes can be seen. A discussion of the kinetics of these processes is presented.