| Synthesis and Characterization of BaFeO3, (Ba,Bi)FeO3, and Related Epitaxial Thin Films and Nanostructures |
Jan-2009 |
116 pages |
| Authors:
David P Norton; FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
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 | There is significant interest in identifying and manipulating new materials that have unique magnetic, dielectric, and transport properties. Single phase and artificially structured materials for which more that one electromagnetic functionality coexists are particularly interesting. In this project, the synthesis of epitaxial thin films and multilayered structure with potential to display these attributed were examined. |
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| Investigation into the Effect of Reagent Choice on the Dielectric Properties of the Ferroelectric Oxides Ba(MTa)0.05Ti0.9O3 (where M=Sc, Er, Ho or Y) |
01-Oct-2008 |
24 pages |
| Authors:
Virginia L Miller; Steven C Tidrow; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| This report investigates the effects of reagent choice on the physical properties of ferroelectric oxides of the composition Ba(MTa)0.05Ti0.9O3 (M=Sc, Er, Ho or V). These materials are of particular interest because they possess relatively low to medium dielectric constants and improved tunabilities. In this project, samples of Ba(MTa)0.05Ti0.9O3 (M=Sc, Er, Ho or Y) were prepared using two different synthetic methods. The first method consisted of heating a stoichiometric mixture of ... |
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| Flux Pinning Enhancement in YBa2Cu3O7-x Films with BaSnO3 Nanoparticles |
01-Oct-2008 |
7 pages |
| Authors:
P N Barnes; Chakrapani V Varanasi; J Burke; L Brunke; I Maartense; T J Haugan; E A Stinzianni; K A Dunn; P Haldar; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| Nanoparticles of BaSnO3 were incorporated into YBa2Cu3O7-x (YBCO) films on LaAlO3 substrates for magnetic flux pinning enhancements. More than an order of magnitude improvement in the high field magnetization Jc at 6 T at 77 K was observed as compared to regular YBCO films. The irreversibility field (Hirr) was increased to 8.5 T at 77 K and to 13.4 T at 65 K. The in-field transport current measurements confirmed an ... |
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| Development of Improved Microwave Dielectric Materials and Devices using Advanced Experimental and Theoretical Methods |
17 APR 2008 |
33 pages |
| Authors:
Nathan Newman; Van Schilfgaarde; ARIZONA STATE UNIV TEMPE DEPT OF ELECTRICAL ENGINEERING
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| Our work has made important progress towards developing a fundamental understanding of the microscopic mechanism that causes loss in high performance microwave dielectrics, and can explain why some dielectric materials exhibit markedly better performance than others. Ab-initio electronic structure calculations elucidated the physical reason for this desirable microwave properties in Ba(Cd1/3Ta2/3)O3 (BCT) and Ba(Zn1/3Ta2/3)O3 (BZT). The presence of significant charge transfer between cation d-orbitals provides a degree of covalent directional ... |
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| Development of Artificial Y-Type Hexaferrites |
01 MAY 2003 |
2 pages |
| Authors:
C. Vittoria; NORTHEASTERN UNIV BOSTON MA
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| We have developed a technique to orient particles of Y-type hexaferrite in which the c-axis of the particles are oriented perpendicular to a plane As such, that plane becomes necessarily the easy plane of magnetization. For microwave device application the easy plane of magnetization is chosen as the plane to deposit a metallic microstrip and related circuit patterns. The technique entails the rotation of an external magnetic field in the ... |
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| Materials Research Society Fall Meeting(1998). Symposium Q: High Temperature Superconductors - Materials Challenges |
30 SEP 1999 |
5 pages |
| Authors:
Joseph Budnick; Siu-Wai Chan; Wei-Kan Chu; John Kirtley; Keichi Tanabe; MATERIALS RESEARCH SOCIETY WARRENDALE PA
|
| Symposium Q on High Temperature Superconductors-Materials Challenges, covered a variety of HTS Materials issues. The symposium lasted three and half days with two evening poster sessions. A total of 135 papers were delivered, and 80 of those were oral presentations. The attendance was usually around 150 while a few keynote speakers drew larger audiences of over 200. A good fraction of the participants were from Japan and Europe. Overall, the ... |
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| BAF2/GAAS Electronic Components. |
03 AUG 1999 |
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| Authors:
Francisco Santiago; Tak K. Chu; DEPARTMENT OF THE NAVY WASHINGTON DC
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 | Metal insulator semiconductor field effect transistors (MISFETs), charge coupled devices (CCDs), and capacitors based on an epitaxial barium fluoride (BF) insulator layer deposited directly onto a single crystal gallium arsenide (GaAs) substrate. |
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| Mechanical Properties of Ferroelectric Composite Thin Films Fabricated by the Pulsed Laser Deposition Method |
MAY 1998 |
23 pages |
| Authors:
Costas G. Fountzoulas; Somnath Sengupta; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Barium strontium titanium oxide (BSTO) ferroelectric films of various nominal thicknesses were deposited by the pulsed laser deposition (PLD) technique on single crystals of sapphire at substrate temperatures varying from 30 to 700 deg C. X-ray analysis showed that the thin films were amorphous up to 500 deg C, while at 700 deg C, they were polycrystalline. The microstructure of the thin films was columnar at all substrate temperatures. The ... |
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| Replacement of First Fire Composition in M127A1 Ground Illumination Signal |
DEC 1997 |
23 pages |
| Authors:
Russell N. Broad; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ WARHEADS ENERGETICS AND COMBAT SUP
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| A study was conducted to replace the first fire composition in the ground illumination signal. The original first fire composition contained tetranitro carbazole, a sole source material, and barium nitrate, a toxic material. Program costs were minimized by choosing a presently used first fire composition as a replacement. A data base of such compositions was created. It was used to pick candidate replacement compositions. The ... |
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| Boundary Effects in High-Tc Superconducting |
DEC 96 |
4 pages |
| Authors:
A. Kapitulnik; STANFORD UNIV CA
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| This work examines the thermal boundary resistance between high-Tc superconducting films and insulating substrates. In particular we compare c-axis and a-axis films and different oxygen stoichiometries. Comparison of c-axis films shows very little temperature dependence; a-axis films show strong temperature dependence from 100 K to room temperature. This temperature dependence disappears upon reducing the oxygen content of the films. |
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| Effects of Geometric and Material Parameters on Behavior of Fiber Composites |
15 MAY 96 |
11 pages |
| Authors:
I. M. Daniel; R. D. Cordes; NORTHWESTERN UNIV EVANSTON IL
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| The objective of this investigation is to study the effects of constituent properties (fiber, matrix, interphase) and geometric parameters (fiber volume ratio, fiber packing) on the overall behavior of brittle matrix composites. Four model composite materials were studied, a silicon carbide fiber/barium borosilicate glass system, a polyvinyl alcohol fiber/epoxy system, and two optic fiber/epoxy systems. Single fiber tests were used to characterize interfacial properties. Multiple fiber composite models were made ... |
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| Improved, High Power, Eye Safe, Solid State Laser |
MAR 96 |
44 pages |
| Authors:
R. A. Stolzenberger; CRYSTAL ASSOCIATES INC WALDWICK NJ
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| The Phase I SBlR technical results demonstrate the feasibility of a solid-state Raman shifter to generate 1.56 micron light. The 1.56 micron laser source was based on a compact, Nd:YAG-pumped, intracavitv Barium Nitrate, solid- state Raman shifter (SSRS). The experiment demonstrated diffraction limited, 1. 56 micron output at greater that 250 mJ/pulse, with an optical-to-optical conversion efficiency of 60%. Some nice features of this novel technique were a very large ... |
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| Thin Films of Novel Ferroelectric Composites |
MAY 95 |
13 pages |
| Authors:
S. Sengupta; L. C. Sengupta; S. Stowell; D. P. Vijay; S. B. Desu; ARMY RESEARCH LAB WATERTOWN MA MATERIALS DIRECTORATE
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| Composites of BSTO combined with other non electrically active oxides have demonstrated adjustable electronic properties which can be tailored for use in various electronic devices. These novel composites of barium strontium titanate (BSTO) and Oxide III compounds have already exhibited promising results in their ceramic form. The additive oxides modify the dielectric constant, tunability (change in the dielectric constant with applied voltage), and dielectric loss of the material. One application ... |
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| SDIO: Discovering Superconducting Materials at High Temperatures |
25 AUG 94 |
3 pages |
| Authors:
Francis J. DiSalvo; CORNELL UNIV ITHACA NY DEPT OF CHEMISTRY
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| The research funded under this grant focused on the layered structure compounds BaNIS2 and BaCoS2. The former is a metallic conductor while the latter is a magnetic Mott insulator. We planned doping studies to study the effects of both disorder and the crossover to the metallic state. It is hoped that doping a Mott insulator to the metallic state might produce a high temperature superconductor. Unfortunately, due to the termination ... |
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| BaF2/GaAs Electronic Components. |
19 MAY 1994 |
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| Authors:
Francisco Santiago; Tak-Kin Chu; DEPARTMENT OF THE NAVY WASHINGTON DC
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| Metal insulator semiconductor field effect transistors (MISFETs), charge coupled devices (CCDs), and capacitors based on an epitaxial barium fluoride (BF2) insulator layer deposited directly onto a single crystal gallium arsenide (GaAs) substrate |
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| Basic Optical Studies of High T sub c Oxide Superconductors |
15 JUN 93 |
9 pages |
| Authors:
M. S. Dresselhaus; G. Dresselhaus; MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR MATERIALS SCIENCE AND ENGINEE RING
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| During the 1992-93 year of the research program on Basic Optical Studies of High T sub c Oxide Superconductors, the effort was focused on a number of projects. The collaborative study of the microwave properties of superconductors with researchers at Rome Labs and the MIT Lincoln Laboratory continued and significant results were obtained on the microwave behavior in the non-linear high rf power regime for YBa2Cu307-x and this work will ... |
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| EM Properties of High Tc Superconductors |
JUN 92 |
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| Authors:
S. Sridhar; NORTHEASTERN UNIV BOSTON MA
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| The aim of this contract was to study the factors influencing microwave properties o high TC superconductors, via fundamental measurements on high quality thin film and single crystal materials. Two principal lines of investigation were pursued: In single crystals of Y,Ba2CU307-6 (Tc=93K) ultrasensitive rf methods were used to stud the penetration depth A, lower critical fields Hc1 and vortex pinning forces. The penetration depth and surface resistance were found to ... |
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| High Power Blue-Green B-BaB2O4 Optical Parametric Oscillator |
APR 92 |
28 pages |
| Authors:
Bruce P. Boczar; Thomas W. Hamilton; NAVAL AIR WARFARE CENTER AIRCRAFT DIV WARMINSTER PA
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| A high power, pulsed beta barium borate optical parametric oscillator pumped by a frequency tripled Nd:YAG laser has been constructed and characterized. Anti-reflection coatings, oscillation thresholds, pump pulse duration, pulsewidth reduction, and spectral linewidths have been evaluated. Output pulse energies of 29 mj and an average power of 0.27 watts has been achieved at 480 nm. |
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| Effect of the Addition of A1203 AND Ag20 on the Morphology and Superconductivity of YBa(2)Cu(3)3O(6+x) Ceramic Materials |
11 JAN 92 |
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| Authors:
A. S. Rao; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SHIP MATERIALS ENGINE ERING DEPT
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| In order to produce YBa2CU306+x ceramic material with find particle size and good superconducting properties, both A1203 and Ag20 were added to YBa2CU306+X during sintering. The results suggest that the addition of both A1203 and Ag20 does not decrease the average particle size of YBa2CU306+x; however, the superconducting properties degrade with an increase in the A1203 concentration. In composites containing high additive concentration, fine structure resembling that of fine pits ... |
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| Beta-Barium Borate Optical Parametric Oscillator |
15 AUG 91 |
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| Authors:
C. L. Tang; CORNELL UNIV ITHACA NY
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| A Beta-Barium Borate Optical Parametric Oscillator (BBO OPO) has been constructed and shipped to the Army laboratory at White Sands. This OPO is a truly continuously tunable source with a very large spectral coverage. It is pumped at the third harmonic of Nd:YAG or 335 nm. The output is continuously tunable over the entire spectral range from 450 nm to 2.5 microns with relatively high efficiency. The tuning is completely ... |
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| Optimal Guidance for High-Order and Acceleration Constrained Missile. |
MAY 1991 |
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| Authors:
I. Rusnak; L. Meir; DREXEL INST OF TECH PHILADELPHIA PA DEPT OF ELECTRICAL ENGINEERING
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| Electrical Characteristics of Aluminum-Zirconium Oxide-barium Magnesium Fluoride-p Silicon MIS Capacitors, |
05 APR 1991 |
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| Authors:
T. S. Kalkur; R. Y. Kwor; L. Levenson; L. Kammerdinner; COLORADO UNIV AT COLORADO SPRINGS
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| The Barium Magnesium Fluoride films have been deposit on p-Si wafers at a temperature in the range of 400-450 deg C in an ion assisted deposition system. X-ray diffraction analysis shows that the films are polycrystalline in nature. The BMF films were encapsulated with an electron be evaporated ZrO2 film of thickness 300 deg A. The capacitance-voltage (C-V) characteristics of Aluminum-ZrO2-BMF-p Si MIS capacitors show hysteresis and the direction of ... |
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| UHV Processing of Ferroelectric Barium Magnesium Fluoride Films and Devices, |
05 APR 1991 |
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| Authors:
S. Sinharoy; D. R. Lampe; H. Buhay; M. H. Francombe; WESTINGHOUSE SCIENCE AND TECHNOLOGY CENTER PITTSBURGH PA
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| Barium magnesium fluoride (BaMgF4) has recently emerged as a strong candidate for application as the gate dielectric in ferroelectric random access memory (FERRAM) devices with nondestructive readout (NDRO). In earlier papers we reported the successful growth of oriented BaMgF4 films on Si(100) and other substrates in a ultrahigh vacuum (UHV) system, as well as the results of the structural and electrical characterization of these ferroelectric films. In the present paper, ... |
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| Proximity-Coupled HTSC Materials and Devices |
15 FEB 91 |
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| Authors:
William J. Skocpol; BOSTON UNIV MA DEPT OF PHYSICS
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| High Temperature Superconducting Films and Crystals |
02 FEB 91 |
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| Authors:
Theodore H. Geballe; Aharon Kapitulnik; STANFORD UNIV CA DEPT OF APPLIED MECHANICS
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| A High Temperature Molten Salt Thermal Electrochemical Cell. |
12 FEB 1990 |
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| Authors:
Edward J. Plichta; Wishvender K. Behl; DEPARTMENT OF THE ARMY WASHINGTON DC
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| This invention relates in general to a high temperature molten salt thermal electrochemical cell and in particular to such a cell including cobalt oxide (Co3O4) as the cathode material. High temperature molten salt thermal electrochemical cells are widely used as power sources for projectiles, rockets, bombs, mines, missiles, decoys, jammers and torpedoes. These are also used as fuses. Thermal electrochemical cells are reserve-type cells that can be activated by heating ... |
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| Method of Making a Long Life High Current Density Cathode from Tungsten and Iridium Powders Using a Mixture of Barium Peroxide and a Coated Emitter as the Impregnant. |
20 NOV 1989 |
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| Authors:
Louis E. Branovich; Bernard Smith; Gerard E. Freeman; Donald W. Eckart; DEPARTMENT OF THE ARMY WASHINGTON DC
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| A long life high current density cathode is made from a mixture of tungsten and iridium powders by processing the mixture of powders with an activator into a porus billet, and then impregnating the billet with a mixture of barium peroxide and a coated emitter by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts. Patent applications; Powder metallurgy; Powder metals particle size; ... |
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| New Electronic Materials and CO2 Reduction |
10 NOV 89 |
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| Authors:
Aaron Wold; BROWN UNIV PROVIDENCE RI DEPT OF CHEMISTRY
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| Research in the area of catalysis at Brown deals with the development of low temperature synthetic methods for the preparation of well-dispersed catalysts (Iron oxide, Chromic oxide, Rhodium oxide and Nickel oxide) on several oxide supports (ZrO2, TiO2). Physical methods, such as x-ray diffraction, magnetic susceptibility and temperature programmed reduction, are used to study the interaction between the dispersed metal oxide and the support. The extent of substitution of nickel ... |
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| Bulk Wave Characterization of High Tc Superconductors |
01 NOV 89 |
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| Authors:
Moises Levy; Bimal Sarma; WISCONSIN UNIV-MILWAUKEE DEPT OF PHYSICS
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| The objective of this research is to characterize high T(c) superconductors with ultrasonic waves. A peak in ultrasonic attenuation has been observed at the superconducting phase transition of the thalium superconducting compound with a T(c) = 103 K. The position of this peak is independent of frequency and therefore should not be produced by a relaxation mechanism. It may be produced by interactions with fluctuations associated with the superconducting phase ... |
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| Effects of Different Fabrication Techniques on the Yttrium-Barium-Copper Oxide High Temperature Superconductor |
DEC 88 |
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| Authors:
Paul A. Rhea; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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| This study examines how several different parameters were changed in the yttrium-barium-copper oxide superconductor when the fabrication techniques were altered by using different barium precursors, including barium peroxide and barium carbonate; sintering at different temperatures, including 850, 900, 950 C; and annealing in an above ambient oxygen environment. Twelve different pellets were fabricated, and measurements were taken on them which included density, x-ray diffraction, critical temperature, critical current density, and ... |
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| The Effect of Energetic Charged Particle Bombardment on the Properties of Thin Films of High Tc Superconductors |
01 OCT 88 |
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| Authors:
Douglas B. Chrisey; NAVAL RESEARCH LAB WASHINGTON DC
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| The effects of low fluence ( < 10 to the 14th power/sq cm) 63 MeV H(+) and 65 MeV He2(+) irradiation of prototype thin films of YBa2Cu3O(7 - delta) produced by a plasma arc spray technique. The observed change in the resistance versus temperature behavior is much more dramatic than that observed for films produced by other techniques and resembles qualitatively a bond percolation threshold. The radiation sensitivity of these ... |
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| X-Ray Photoelectron Spectroscopy Study of Samples in the Y-Ba-Cu-O system |
OCT 88 |
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| Authors:
L. F. Aprigliano; B. Friedman; R. J. Stockhausen; DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP MATERIALS ENGINEERING DEPT
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| Superconducting ceramics that have critical temperatures which exceed the boiling point of liquid nitrogen (77 K) have been discovered. Preliminary studies both in the United States and Japan indicate that the superconducting properties of these ceramics can degrade with exposure to water vapor during processing. X ray photoelectron spectroscopy (XPS) is a possible method with which to study this problem. The goal of this research was to determine if there ... |
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| Preparation of the High-Tc Superconductor YBa2Cu3O(7-x) Using Organometallic Precursors |
21 JUL 88 |
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| Authors:
Leonard V. Interrante; Zhiping Jiang; David Larkin; RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF CHEMISTRY
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| Organic soluble precursors to the high Tc 1-2-3 superconductor, YBa2Cu3O7-x, have been prepared using polyesters derived from the interaction of citric acid (CA) or ethyl-enediaminetetraacetric acid (EDTA) with ethylene glycol. Mixtures of the nitrate, carbonate and/or acetate salts of the three metal ions with CA or EDTA and ethylene glycol were heated to obtain homogeneous green solids containing the desired 1:2:3 ratios of Y3+, Ba2+, and Cu2+ ions. Pyrolysis at ... |
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| Tunneling Microscopy of Superconductors and Tunneling Barriers |
31 MAY 88 |
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| Authors:
Alex De Lozanne; TEXAS UNIV AT AUSTIN DEPT OF PHYSICS
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| Thin films of high temperature superconductors were made by sputtering and by co-evaporation. The former method produced thin films of YBaCuO which were completely superconducting at 82 K with 6 K transition widths. A new method was developed at the University of Texas which produced films of YBaCuO on strontium titanate that were superconducting at 84 K. This method minimizes the process temperature and produces films which are superconducting without ... |
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| Detectors of Infrared Radiation Based on High T(c) Superconducting YBCO Films |
23 FEB 88 |
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| Authors:
T. H. Geballe; STANFORD UNIV CA DEPT OF APPLIED PHYSICS
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| We achieved control over the orientation and microstructure of the thin films of YBa2Cu30(7-x)(YBCO). We elucidated the optical properties of YBCO, including the penetration depth (which turned out to be rather small) and the optical anisotropy (which is rather large). We have observed photo-induced signals (i.e. changes in resistivity) of YBCO films in superconducting state as well as in the normal state upon illumination with short pulsed IR radiation generated ... |
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| Substantially Single Phase Superconducting Oxide Ceramics having a Tc above 85 K and a Method of making the Ceramic. |
22 FEB 1988 |
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| Authors:
Syed B. Quadri; Louis E. Toth; Michael S. Osofsky; Steven H. Lawrence; Donald U. Gubser; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A substantially single phase superconducting composition is formed from a of 1:2:3 molar ratio of fine powders of a superconducting rare earth oxide, CuO, and BaCo3. The mixed powders and shaped articles formed from the mixed powders are calcined, sintered, and cooled in an oxygen containing atmosphere. The cooling step is done slowly to improve the superconducting properties. The article formed is a substantially single phase superconducting composition. |
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| Processing and Additive Effects of ZrO2 on Microstructure and Dielectric Properties of BaTiO3 Ceramics |
28 DEC 87 |
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| Authors:
T. R. Armstrong; L. M. Morgens; A. K. Maurice; R. C. Buchanan; ILLINOIS UNIV AT URBANA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| Dielectric properties and structure of BaTiO3 ceramics have been shown to be significantly influenced by small additions of ZrO2. Scanning Electron Microscopy(SEM) and Transmission Electron Microscopy(TEM) observations revealed enhanced microstructural uniformity and retarded grain growth with ZrO2 addition, depending on sintering temperature (T sub S). For T sub S <1320 C, TEM analysis showed ZrO2 at the grain boundaries as discrete particles in a bandwidth of + or - 50 ... |
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| Composite Ceramic Superconducting Filaments for Superconducting Cable |
13 NOV 87 |
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| Authors:
John W. Halloran; CERAMICS PROCESS SYSTEMS CORP CAMBRIDGE MA
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| This is the first progress report of a five month program to demonstrate the feasibility of manufacturing superconducting wires from YBa2Cu307-x, consisting of a small ceramic core with a copper cladding. The critical current will be enhanced by creating a fiber texture in the ceramic using a combination of green particle orientation and controlled recrystallization. The ceramic core will be manufactured by solution dry- spinning of a mixture of the ... |
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| Superconductivity of Thin Film Intermetallic Compounds |
30 SEP 87 |
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| Authors:
A. M. Goldman; MINNESOTA UNIV MINNEAPOLIS SCHOOL OF PHYSICS AND ASTRONOMY
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| Investigations of both macroscopic and microscopic properties of thin film superconducting materials have been carried out. Compounds under study prior to the discovery of high-Tc superconductors, were either technologically significant, or involved possible unique mechanisms for superconductivity whose realization might extend the range of critical parameters. These include low carrier density superconductors, selected Heavy Fermion Compounds, and Chevrel Phase superconductors. Among the low-carrier density systems were films of Lead Tellurium ... |
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| Composite Ceramic Superconducting Filaments for Superconducting Cable |
05 JAN 87 |
|
| Authors:
John W. Halloran; CERAMICS PROCESS SYSTEMS CORP CAMBRIDGE MA
|
| This is the second progress report of a five month program to demonstrate the feasibility of manufacturing superconducting wires form YBa2Cu307-x, consisting of a small ceramic core with a copper cladding. The ceramic core is to be produced from a dry spun ceramic fiber, sintered to create a fiber texture to enhance critical current. The sintered fiber is to be clad with copper by electroplating. The sintering and microstructure development ... |
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| Research on Millimeter Wave Dielectric Materials |
AUG 86 |
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| Authors:
J. R. Oliver; R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| Much of the early effort in this program was devoted to single crystal strontium barium niobate (SBN), a tungsten bronze with an unusually large room-temperature dielectric response. More recently, other tungsten bronzes such as potassium lithium niobate (KLN) and barium strontium potassium sodium niobate (BSKNN) have been prepared and studied to elucidate the role of unfilled crystallographic sites in influencing dielectric loss. Currently, we are developing preparation techniques for morphotropic ... |
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| Information on the Impact Parameter Dependence of the BAI Yields BaI(V=8)+H Reaction |
15 JUL 86 |
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| Authors:
Chifuru Noda; John S. McKillop; Mark A. Johnson; Janet R. Waldeck; Richard N. Zare; STANFORD UNIV CA DEPT OF CHEMISTRY
|
| Using selectively detected laser-induced fluorescence, the rotational state distribution of the BaI product has been measured for the beam-gas reaction Ba + HI yield BaI (v = 8) + H. Owing to the highly constrained kinematics for this system, these measurements can be used to derive the reaction probability as a function of the impact parameter for this channel, called the specific opacity function, once the reaction probability as a ... |
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| Piezoelectric and Electrostrictive Materials for Transducer Applications |
JUL 86 |
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| Authors:
L. E. Cross; R. E. Newnham; G. R. Barsch; J. V. Biggers; PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
|
| On the topic piezolelectric composites, work over the year has focused primarily upon materials with 0:3 phase connectivity. Using chemically co-precipitated powders with high purity and surface perfection, it has been possible to raise the poling field substantially and realize markedly improved properties in lead titanate based materials. X-ray measurements confirm excellent poling and the dhgh figure of merit of 4200x10 to the minus 15th power sq m2/N is comparable ... |
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| Studies of Phase-Conjugate Optical Device Concepts |
JUN 86 |
|
| Authors:
Pochi Yeh; Ian McMichael; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| This contract studies the phase-reversal property of optical phase conjugation for navigational and other device applications. The study focuses on the development of the phase-conjugate fiber-optic gyro and the generation of new device concepts. Although much attention is paid to the aberration correction property of phase conjugation, little attention is paid to the phase reversal property. The phase-reversal property has important applications in inertial navigation devices. The general problem for ... |
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| Intrinsic Mechanisms of Multi-Layer Ceramic Capacitor Failure |
APR 86 |
|
| Authors:
L. C. Burton; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG COLL OF ENGINEERING
|
| It has been established that the dominant charge carrier of leakage current in the BaTi03 based X7R ceramic that we have measured is the electron. Galvanic cell measurements yield oxygen ion transport numbers of essentially zero. The major effect of oxygen movement is not ionic current, but degradation. A generic degradation current-time curve is discussed. Two models for leakage current vs time are presented: one based on oxygen vacancy (and ... |
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| Fabrication of Low-Loss Halide Glass Fibers |
SEP 85 |
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| Authors:
J. Wysocki; HUGHES RESEARCH LABS MALIBU CA
|
| The primary objective of this program was to develop ultralow-loss fibers for use in long-distance Navy communications systems. Accomplishments of that goal were directed toward the investigation of materials that would transmit in the infrared, as well as fiber drawing processes for these materials. Major emphasis has been placed on fabrication of chloride and fluoride-chloride glasses. These glasses were subsequently doped with a sulfide. Heavy-metal fluoride glasses, which are generally ... |
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| Impregnant Composition in Dispenser Cathodes |
12 AUG 85 |
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| Authors:
H. K. A. Kan; R. R. Seaver; AEROSPACE CORP EL SEGUNDO CA CHEMISTRY AND PHYSICS LAB
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| The compositions of impregnants inside B-type dispenser cathodes containing barium calcium aluminates were examined by means of quantitative microprobe analysis. The impregnant inside the porous tungsten structure was supported with plastic in order to prevent damage when the cathode was sectioned. The impregnant compositions were found to be consistently deficient in CaO when compared to the nominal composition. Variations and reproducibility in composition are discussed. Keywords include: Cathodes; Dispenser cathodes; ... |
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| Nonlinear Materials for the Millimeter Spectral Region |
JUL 85 |
|
| Authors:
M. B. Klein; B. A. Wechsler; D. Rytz; HUGHES RESEARCH LABS MALIBU CA
|
| Nonlinear materials offer great promise for use in devices such as phase shifters, modulators, switches, and frequency multipliers at frequencies above 50 GHz. State-of-the-art phase shifters (using ferrites) and power sources are inefficient at high frequencies. By contrast, the efficiencies for electro- optic phase shifting and harmonic generation increase with frequency, and devices based on these effects offer high-speed, low-loss operation over a wide spectral range. Ferroelectrics are particularly promising ... |
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| Multilayer Capacitor Dielectrics Produced from Metallo-Organic Precursors |
30 JUN 85 |
|
| Authors:
R. W. Vest; G. M. Vest; PURDUE UNIV LAFAYETTE IN TURNER LAB FOR ELECTROCERAMICS
|
| The metallo-organic decomposition (MOD) process for preparing films or powders has a number of advantages over conventional processes. The metallo- organic compounds used in the present study had oxygen as the hetero atom to bond a metal atom to an organic ligand. These compounds were each dissolved in an appropriate solvent and the solutions mixed to achieve the desired stoichiometry. After adjusting the rheology, the formulation was deposited on an ... |
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| Multilayer Capacitor Dielectrics Produced from Metallo-Organic Precursors |
29 APR 85 |
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| Authors:
R. W. Vest; G. M. Vest; PURDUE UNIV LAFAYETTE IN TURNER LAB FOR ELECTROCERAMICS
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| The metallo-organic decomposition (MOD) process for preparing films or powders has a number of advantages over conventional processes. The metallo- organic compounds used in the present study had oxygen as the hetero atom to bond a metal atom to an organic ligand. This report is divided into three parts. The first details studies of the kinetics of formation of BaTiO3 and PbTiO3 by the MOD process, and demonstrates that the ... |
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