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Your search keyword '"Venturini, E.L."' showing total 145 results
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145 results on '"Venturini, E.L."'

3. Dielectric properties and phase transitions of Cd2Nb2O7: Effects of pressure and temperature

Author

Samara, G.A., Venturini, E.L., and Boatner, L.A.

Subjects
Phase transformations (Statistical physics) -- Analysis, Hydrostatic pressure -- Analysis, Physics
Abstract

A study of the effects of hydrostatic pressure on the dielectric response of single crystal Cd2Nb2O7 (CNO) is conducted over the temperature range of 80-450 K. Pressure had a relatively weak influence on the various overlapping dielectric relaxations below 200 K, but the results revealed a dipolar relaxation in the 350-400 K region.

Published
2006

5. Growth of TlBa2CaCu2O7 thin films using a controlled Tl-oxide source during processing

Author

Siegal, M.P., Missert, N., Venturini, E.L., Newcomer, P.P., Dominguez, F., and Dunn, R.

Subjects
Thin films -- Electric properties, High temperature superconductors -- Research, Crystals -- Growth, Superconductors -- Electric properties, Business, Electronics, Electronics and electrical industries
Abstract

A two-zone thallination furnace was employed to grow smooth TlBa2CaCu2O7 thin films on LaAlO3 substrates from oxide precursors. The experiment, which achieved control of the thallium oxide vapor pressure, yielded TlBa2CaCu2O7 films with high phase purity, a transition temperature of approximately 87 K and a critical current density of 2,000 kA/cm2 at low field and 40 K. In addition, it demonstrated the feasibility of preparing high-quality TlBa2CaCu2O7 thin films at temperatures near 825 degrees Celsius.

Published
1995

6. Two-zone equilibria of Tl-Ca-Ba-Cu-O superconductors

Author

Aselage, T.L., Venturini, E.L., and Van Deusen, S.B.

Subjects
High temperature superconductors -- Research, Transition temperature -- Analysis, Bulk solids -- Research, Physics
Abstract

Transition temperatures (Tc) of the Tl family of superconductors are insensitive to carrier density charges and equilibrium conditions, and can be reproduced easily to facilitate the study of phase equilibria. Tl family of superconductors are made of phases which can be referred to by their Tl:Ca:Ba:Cu ratios and are characterized by high Tcs. The study of phase equilibria in the Tl-Ca-Ba-Cu-O systems also provides information for two zone synthesis of bulk materials and thick and thin films.

Published
1994

7. Thickness dependence of electrodynamic properties of TICaBaCuO thin films

Author

Martens, J.S., Hietala, V.M., Venturini, E.L., and Lee, W.Y.

Subjects
High temperature superconductivity -- Usage, Electrodynamics -- Analysis, Physics
Abstract

The examination of thickness dependence of the electrodynamic properties of Tl2Ca2Ba2Cu3Ox films after correction for geometrical effects, shows that the surface resistance increases for very thin or thick films as it is persistent with the presence of a poorly superconducting layer which was detected with magnetization measurements. The examination of temperature dependence of surface resistance at low temperatures enabled it to fit a multigap model.

Published
1993

8. Synthesis and processing of thin films in the Tl-Ca-Ba-Cu-O system

Author

Ginley, D.S., Martens, J.S., Venturini, E.L., Tigges, C.P., Ashby, C., and Volk, S.

Subjects
Copper oxide superconductors -- Research, Thin films -- Research, High temperature superconductors -- Research, Business, Electronics, Electronics and electrical industries
Abstract

A discussion on ex-situ process parameters affecting film growth and processing during the synthesis of high-temperature thin films is presented. It tackles performance issues related to precursor behavior, sintering techniques, annealing factors, etching procedures and contact materials of the thallium-calcium-barium-copper-oxide system. These are optimized to derive an accurate stoichiometry for the Tl2Ca2Ba2Cu3O10 and Tl1Ca2Ba2Cu3O9 phases.

Published
1993

9. Spin-dependent transport at silicon grain boundaries

Author

Seager, C.H., Venturini, E.L., and Schubert, W.K.

Subjects
Semiconductors -- Research, Electrical conductivity -- Research, Silicon -- Electric properties, Physics
Abstract

A study was conducted on the spin-dependent transport (SDT) response in weakly doped silicon bicrystal grain boundaries. SDT signal characteristics were found to vary depending on whether samples were illuminated with band-gap light or kept in the dark. Results show that dark SDT signals are asymmetric while band-gap illuminated SDT signals are symmetric. The dark SDT effect is attributed to shifts in the spin-flip k-vector occuring in conduction-band electrons.

Published
1992

11. Dielectric properties of Zr-modified Pb{[Mg.sub.1/3][Ta.sub.2/3]}[O.sub.3] ceramic: Influence of pressure, biasing electric field, and B-site cationic order

Author

Grubbs, R.K., Venturini, E.L., Samara, G.A., Wang, Y., and Setter, N.

Subjects
Zirconium -- Electric properties, Zirconium -- Chemical properties, Zirconium -- Structure, Lead compounds -- Electric properties, Lead compounds -- Chemical properties, Lead compounds -- Structure, Dielectric heating -- Research, Physics
Abstract

The effects of hydrostatic pressure and biasing dc electric field on the relaxor response of samples of Pb{[Mg.sub.1/3][Ta.sub.2/3]}0.95Zr0.05[O.sub.3] with 12%, 15% and 90% B-site cationic order were investigated. A high temperature dielectric relaxation with an activation energy of 1.27 eV is observed for the 90% ordered sample, but not for 12% and 15% ordered samples.

Published
2006

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