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in subjects: "Barium Compounds"  
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Modulated spin and charge densities in cuprate superconductors

Description: Neutron scattering experiments have played a crucial role in characterizing the spin and charge correlations in copper-oxide superconductors. While the data are often interpreted with respect to specific theories of the cuprates, an attempt is made here to distinguish those facts that can be extracted empirically, and the connections that can be made with minimal assumptions.
Date: August 1, 1997
Creator: Tranquada, J.M.
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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.,
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Partner: UNT Libraries Government Documents Department
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Synchrotron x-ray diffraction study of the surface layer in poled ceramic BaTiO{sub 3}

Description: Both unpoled and poled BaTiO{sub 3} were studied by laboratory and synchrotron x-ray sources. The shorter-wavelength synchrotron radiation was used to probe deeper below the surface. Diffraction patterns revealed a distinctive surface layer of the same tetragonal structure as the main BaTiO{sub 3} fraction. A sin{sup 2}{Psi} analysis of peak shift confirmed that no measurable change of elastic strain occurs upon poling, indicating that poling may induce excessive strain that was relieved by mic… more
Date: January 1, 1997
Creator: Ledbetter, H.; Balzar, D.; Stephens, P. W.; Li, J. & Dunn, M. L.
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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.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neutron scattering studies of the magnetic fluctuations in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}

Description: Neutron scattering measurements have been made on the spin fluctuations in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} for different oxygen doping levels. Incommensurability is clearly observed for oxygen concentrations of 6.6 and 6.7 and is suggested for the 6.93. Measurements of the resonance for the O6.6 concentration show that it exists in a broadened and less intense form at temperatures much higher than Tc.
Date: November 5, 1997
Creator: Mook, H.A.; Dai, P.; Hunt, R.D. & Dogan, F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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