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X-ray Absorption Spectroscopy of the Rare Earth orthophosphates

Description: X-ray Absorption Spectroscopy (XAS) of the Rare Earth (RE) 3d levels yields sharp peaks near the edges as a result of strong, quasi-atomic 3d{sup 10}4f{sup n} {yields} 3d-{sup 9}4f{sup n+1} transitions and these transitions exhibit a wealth of spectroscopic features. The XAS measurements of single crystal REPO{sub 4} (RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) at the 3d edge were performed in the total yield mode at beam line 8-2 at the Stanford Synchrotron Radiation Laboratory (SSRL). The XA… more
Date: June 1, 1993
Creator: Shuh, D. K.; Terminello, L. J.; Boatner, L. A. & Abraham, M. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Intermediate-Range Order in Simple Metal-Phosphate Glasses: The Effect of Metal Cations on the Phosphate Anion Distribution

Description: The technique of high-performance liquid chromatography (HPLC) has been used to probe the phosphate anion distribution in a variety of metal phosphate glasses including glasses made with trivalent metal cations (Al, In, Ga, La). The composition of each glass was chosen so that the average phosphate chain length was between 2 and 4 PO{sub 4} tetrahedra. The widths of the resulting phosphate anion distributions were determined directly from an analysis of the HPLC chromatograms. Literature values… more
Date: June 1, 1997
Creator: Sales, B. C.; Boatner, L. A. & Ramey, J. O.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Growth of Large Single Crystals of Mgo

Description: The progressive identification of new high-technology applications and requirements for MgO single crystals in the commercial realm, as well as in DOE and other government-agency project areas, has resulted in an increased demand and international market for this material. Specifically, the demand for MgO crystals in large sizes and quantities is presently increasing due to existing and developing applications that include: (a) MgO substrates for the formation of electro-optic thin films and de… more
Date: June 12, 1997
Creator: Boatner, L. A. & Urbanik, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Growth of Large Detector Crystals. Crada Final Report

Description: In the course of a collaborative research effort between L.A. Boatner of Oak Ridge National Laboratory and Prof. Alex Lempicki of the Department of Chemistry of Boston University, a new highly efficient and very fast scintillator for the detection of gamma-rays was discovered. This new scintillator consists of a single crystal of lutetium orthophosphate (LuPO{sub 4}) to which a small percentage of trivalent cerium is added as an activator ion. The new lutetium orthophosphate-cerium scintillator… more
Date: June 18, 1997
Creator: Boatner, L. A. & Samuelson, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chemical and Ceramic Methods Toward Safe Storage of Actinides Using Monazite. 1998 Annual Progress Report

Description: 'The use of ceramic monazite, (La,Ce)PO{sub 4}, for sequestering actinides, especially plutonium, and some other radioactive waste elements (rare earths e.g.) and thus isolating them from the environment has been championed by Lynn Boatner of ORNL. It may be used alone or, as it is compatible with many other minerals in nature, can be used in composite combinations. Natural monazite, which almost invariably contains Th and U, is often formed in hydrothermal pegmatites and is extremely water res… more
Date: June 1, 1998
Creator: Morgan, P. E. D. & Boatner, L. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Microwave Processing for Advance Electro-Optic Materials

Description: This project addressed the technical and scientific goals of developing new methods for the formation of striation-free single crystals of potassium tantalate niobate. This solid-solution system has the potential for serving as a general electro-optic material with a wide range of optical applications. The performance of the material is, however, severely limited by the effects of compositional inhomogeneity that is generally induced during the single crystal growth process due to the nature of… more
Date: June 1, 2000
Creator: Boatner, L. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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New Crystal-Growth Methods for Producing Lattice-Matched Substrates for High-Temperature Superconductors

Description: This effort addressed the technical problem of identifying and growing, on a commercial scale, suitable single-crystal substrates for the subsequent deposition of epitaxial thin films of high temperature semiconductors such as GaN/AlN. The lack of suitable lattice-matched substrate materials was one of the major problem areas in the development of semiconducting devices for use at elevated temperatures as well as practical opto-electronic devices based on Al- and GaN technology. Such lattice-ma… more
Date: June 24, 2008
Creator: Boatner, L. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Time Resolved Reflectivity Measurements in Pb-Implanted Srtio/Sub 3/

Description: Time resolved optical reflectivity (TRR) is a simple and elegant technique for dynamically monitoring the interface motion that occurs during crystallization of thin films and amorphous layers on crystalline substrates. This in situ technique has enabled measurements of the solid-phase epitaxial regrowth rate of amorphous silicon layers produced by ion implantation to be extended by over five orders of magnitude to rates in excess of 10/sup 6/ /angstrom//s. TRR is also well suited to measuremen… more
Date: June 1, 1989
Creator: McCallum, J. C.; Rankin, J.; White, C. W. & Boatner, L. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Transient Grating in a Knbo{Sub 3}/Ktao{Sub 3} Superlattice

Description: Time-resolved degenerate-four-wave-mixing (DFWM) techniques have been used to characterize the nonlinear optical response of a KNbO{sub 3}/KTaO{sub 3} superlattice grown by pulsed laser deposition on a 1 mm thick, (001)-oriented KTaO{sub 3} substrate. With a 30 psec pulsed laser, the difference in the nonlinear optical response between bulk KTaO{sub 3} and the superlattice was measured. Results indicate that a significant contribution to the response signal is due to the KNbO{sub 3} superlattic… more
Date: June 1, 1998
Creator: Liu, H.; Fernandez, F.; Jia, W. & Boatner, L. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Lattice dynamics of LuPO{sub 4}

Description: Lutetium orthophosphate is an important nonmagnetic host material for rare-earth-activated luminescence applications. We have measured the LuPO{sub 4} phonon density of states and dispersion curves along the [{xi}00],[{xi}{xi}0], and [00{xi}] symmetry directions by neutron spectroscopy using polycrystalline and single-crystal samples. A quantitative analysis of the neutron results was carried out using a lattice-dynamical shell model.
Date: June 1996
Creator: Nipko, J. C.; Loong, C.-K.; Loewenhaupt, M.; Reichardt, W.; Braden, M. & Boatner, L. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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