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Some Preliminary Considerations Concerning the Expected Ovel-All Expansion of Barium Titanate Ceramic

Description: A preliminary mathematical study is made of the maximum expected expansion of barium titanate ceramic. It is noted that there is insufficient physical evidence for a complete answer and some possible mathematical models are discussed and compared.
Date: February 7, 1955
Creator: Kleinecke, D. C.
Partner: UNT Libraries Government Documents Department
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Acute Radiotoxicity of (Ha-La)140 for Rats and Mice. Part III. Effects of Height and Food Intake of Animals Treated with (Ha-La)140

Description: In the (Ha-La)140 experiments mice and rats were injected intraperitonially with toxic doses of radiobarium. The weight curves indicate that there was definite retardation of growth in mice and 2.25 uc/g and in rats at 1.98 uc/g.
Date: unknown
Creator: Snyder, R. H.; Sacher, G. A. & Teresi, J. D.
Partner: UNT Libraries Government Documents Department
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Nanocrystalline BaTiO{sub 3} from gas-condensation process

Description: Nanocrystalline BaTiO{sub 3} can be prepared by gas condensation, with an average particle size as small as 18 nm. The stoichiometry of nanocrystalline BaTiO{sub 3} particles can be controlled precisely and reproducibly. Nanocrystalline BaTiO{sub 3} powders, fabricated by a novel e-beam evaporation method, show good sintering behavior which can be sintered to a high density at a temperature as low as 1200 C and exhibit a relatively large dielectric constant than that of coarse-grained ceramics.… more
Date: December 31, 1996
Creator: Li, S.; Eastman, J. A.; Thompson, L. J.; Bjormander, C. & Foster, C. M.
Partner: UNT Libraries Government Documents Department
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Study of the structure of ferroelectric domain walls in barium titanate ceramics

Description: Structure of 90{degree} ferroelectric domain boundaries in barium titanate ceramics has been studied by means of Transmission Electron Microscopy and High Resolution TEM. Tilts of specific fringes across domain walls are measured on HREM images and Selected Area Diffraction Patterns. They are in a good agreement with the twin model admitted for these domain boundaries. A computerized method has been developed to give access to quantitative information about atomic displacements across these fer… more
Date: February 1, 1995
Creator: Normand, L.; Thorel, A.; Kilaas, R. & Montardi, Y.
Partner: UNT Libraries Government Documents Department
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Identification and Crystal Structure of Barium Hydrogen Phosphate

Description: From abstract: "The report describes the complete structure of barium hydrogen phosphate, Ba HPO4, as determined by means of x-ray diffraction. The crystal is orthorhombic, with cell dimensions given by a=5.71 A b=7.05 A c=4.61 A. The calculated density is 4.15gm/cm[^]3 for two molecules in the unit cell. The space group is C[subscript]2v[superscript]7-pmn. The barium, phosphorus, and two sets of oxygen lie in the plane of symmetry. The third set of oxygens are in general positions. Parameters … more
Date: August 8, 1944
Creator: Mooney, Rose C. L.; Compton, A. H.; Allison, Samuel King, 1900-1965; Stearns, J. C. & Zachariasen, William H. (William Houlder), 1906-1979
Partner: UNT Libraries Government Documents Department
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Electron Requirements of Bonds in Metal Borides

Description: From abstract: "Electrical measurements have been made on CaB6, SrB6, BaB6, YB2, YB4, YB6, and YB12 for the purpose of testing models of the electronic structure of the boron atoms in the four boride types represented. The compounds CaB6, SrB6, and BaB6 were found to be semiconductors. The Hall coefficients of YB4 was also measured, but could not be interpreted because the free electron theory does not provide a theoretical value for comparison with experiment. The results are in agreement with… more
Date: May 28, 1962
Creator: Johnson, Robert W. & Daane, A. H. (Adrian Hill), 1919-
Partner: UNT Libraries Government Documents Department
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Synthesis of nanocrystalline barium-hexaferrite from nanocrystalline goethite using the hydrothermal method: Particle size evolution and magnetic properties

Description: To characterize particle size/magnetic property relationships, 9 to 50 nm in diameter barium hexaferrite, BaFe{sub 12}O{sub 19} (BHF), particles were prepared using a new synthesis route. By replacing the conventional 50 to 100 nm particles of goethite with nanocrystalline goethite produced via the microwave anneal method of Knight and Sylva, nanocrystalline BHF was synthesized using the hydrothermal method. Evolution of particle size and morphology with respect to concentration and heat treatm… more
Date: March 1, 1997
Creator: Penn, R. L.; Banfield, J. F. & Voigt, J.
Partner: UNT Libraries Government Documents Department
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(Ba,Sr)TiO{sub 3} dielectrics: Relationship between bulk and thin film properties

Description: Thin films of complex perovskites have a number of potentially important applications. Of major scientific and practical concern is the scaling of properties as film dimensions are reduced. This paper describes a satisfactory relationship between bulk and thin film dielectric properties of (Ba,Sr)TiO{sub 3}. Relative contributions of strain, A:B cation stoichiometry, and interface are separated to explain temperature dependent dielectric behavior.
Date: December 22, 1999
Creator: Kingon, A. I.; Streiffer, S. K.; Parker, C. B. & Stemmer, S.
Partner: UNT Libraries Government Documents Department
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MOCVD growth and characterization of (Ba{sub x}Sr{sub 1{minus}x})Ti{sub 1+y}O{sub 3+z} thin films for high frequency devices

Description: The authors have investigated the structural and electrical characteristics of (Ba{sub x}Sr{sub 1{minus}x})Ti{sub 1+y}O{sub 3+z} (BST) thin films. The BST thin films were deposited at 650 C on platinized silicon with good thickness and composition uniformity using a large area, vertical liquid-delivery metalorganic chemical vapor deposition (MOCVD) system. The (Ba+Sr)/Ti ratio of the BST films was varied from 0.96 to 1.05 at a fixed Ba/Sr ratio of 70/30, as determined using x-ray fluorescence s… more
Date: January 18, 2000
Creator: Baumann, P. K.; Streiffer, S. K.; Im, J.; Baldo, P.; McCormick, A.; Auciello, O. et al.
Partner: UNT Libraries Government Documents Department
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Ductile grinding of Ba(Sr)TiO{sub 3} detector substrates

Description: Several precision machining techniques have been applied to barium strontium titanate wafers as deterministic replacements for lapping, polishing and reticulation. Surface finishes approaching polish quality have been achieved in less time than normally required, leading to potentially lower manufacturing costs for uncooled FPA`s.
Date: August 1, 1994
Creator: Kahl, W.K.
Partner: UNT Libraries Government Documents Department
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Stoichiometry and Deposition Temperature Dependence of the Microstructural and Electrical Properties of Barium Strontium Titanate Thin Films

Description: Barium Strontium Titanate (BST) was deposited on Pt/ZrO2 / SiO2/Si substrates using liquid source metal organic chemical vapor deposition. A stoichiometry series was deposited with various GrII/Ti ratios (0.658 to 1.022) and a temperature series was deposited at 550 to 700°C. The thin films were characterized using transmission electron microscopy. Both series of samples contained cubic perovskite BST and an amorphous phase. The grain size increased and the volume fraction of amorphous phase de… more
Date: May 1998
Creator: Pena, Piedad
Partner: UNT Libraries
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In-situ TEM crystallization of sol-gel derived BaTiO{sub 3} thin films

Description: Plan view and cross sectional view samples of pyrolyzed Ba-Ti methoxypropoxide films on (100)Si were prepared in the amorphous form. In-situ hot stage experiments were conducted in a Philips CM30 to follow the crystallization process. With time at 750C, large grains nucleated mostly at the BaTiO{sub 3} surface; the regions near the Si did not crystallize.
Date: June 1, 1994
Creator: Mecartney, M. L.; Gust, M. C. & Evans, N. D.
Partner: UNT Libraries Government Documents Department
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Effect of Lamination Conditions on the Gas Permeability and Adhesion Strength of Green Ceramic Tapes

Description: The gas permeability and adhesion strength of laminated green ceramic tapes were determined for samples comprised of barium titanate as the dielectric, and poly(vinyl butyral) and dioctyl phthalate as the main components of the binder mixture. The green tapes were laminated for times of 2-10 min, pressures of 1.8-7 MPa, and temperatures of 35-85C. The adhesion strength, which was measured by a peel test, increased with increasing lamination time, temperature, and pressure. The permeability, wh… more
Date: August 31, 2007
Creator: Krueger, D.
Partner: UNT Libraries Government Documents Department
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Neutron scattering investigation of the magnetic order in single crystalline BaFe2As2

Description: The magnetic structure of BaFe{sub 2}As{sub 2} was determined from polycrystalline neutron diffraction measurements soon after the ThCr{sub 2}Si{sub 2}-type FeAs-based superconductors were discovered. Both the moment direction and the in-plane antiferromagnetic wavevector are along the longer a-axis of the orthorhombic unit cell. There is only one combined magnetostructural transition at {approx}140 K. However, a later single-crystal neutron diffraction work reported contradicting results. Here… more
Date: January 1, 2008
Creator: Bao, Wei; Qiu, Y.; Kofu, M.; Lee, S. H.; Chang, S.; Wu, T. et al.
Partner: UNT Libraries Government Documents Department
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The electromechanical properties of tetragonal BaTiO{sub 3} and PbTiO{sub 3} single crystals

Description: The velocities of propagation for longitudinal and transverse sound waves in various directions have been measured by Brillouin scattering on high-quality mono-domain single crystals of BaTiO{sub 3} and PbTiO{sub 3}. Using these velocities and also the dielectric permittivities measured by the impedance method and by Raman spectroscopy, a complete set of elastic stiffness moduli C{sub ijkl}, piezoelectric constants e{sub rij}, and dielectric permittivity {epsilon}{sub ij} has been determined at… more
Date: July 1, 1993
Creator: Li, Z.; Foster, C. M.; Grimsditch, M. & Chan, S. K.
Partner: UNT Libraries Government Documents Department
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Pseudogap and Incommensurate Magnetic Fluctuations in YBa{sub 2}Cu{sub 3}O{sub 6.6}

Description: Unpolarized inelastic neutron scattering is used to study the temperature and wave vector dependence of the dynamical magnetic susceptibility, {xi}`` (q,{omega}), of a well characterized single crystal YBa{sub 2}Cu{sub 3}O{sub 6.6} (T{sub c} = 62.7 K). We find that a pseudogap opens in the spin fluctuation spectrum at temperatures well above T{sub c}. We speculate that the appearance of the low frequency incommensurate fluctuations is associated with the opening of the pseudogap. To within the … more
Date: July 24, 1997
Creator: Dai, P., Mook, H.A.,
Partner: UNT Libraries Government Documents Department
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