236 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Superconductors"  
Results: 1 - 24 next
open access

Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation

Description: Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation at 300/sup 0/ K were investigated by transmission electron microscopy. Threshold energies for the production of visible defects were determined to be 152 keV and 131 keV (+- 7 keV) in directions near the a and b (b > a) axes (both perpendicular to c, the long axis in the orthorhombic structure), respectively. During above threshold irradiations in an electron flux of 3 x 10/sup 18/ cm/sup -2/ s/sup -1/, extended… more
Date: December 1, 1987
Creator: Kirk, M.A.; Baker, M.C.; Liu, J.Z.; Lam, D.J. & Weber, H.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Program summaries for 1979: energy sciences programs

Description: This report describes the objectives of the various research programs being conducted by the Chemical Sciences, Metallurgy and Materials Science, and Process Science divisions of the BNL Dept. of Energy and Environment. Some of the more significant accomplishments during 1979 are also reported along with plans for 1980. Some of the topics under study include porphyrins, combustion, coal utilization, superconductors, semiconductors, coal, conversion, fluidized-bed combustion, polymers, etc. (DLC) more
Date: December 1, 1979
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Analytical Chemistry Laboratory progress report for FY 1989

Description: The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1989 (October 1988 through September 1989). The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. In addition, the ACL conducts a research program in analytical chemistry, works… more
Date: December 1, 1989
Creator: Green, D. W.; Heinrich, R. R.; Graczyk, D. G.; Lindahl, P. C. & Erickson, M. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Flux pinning and flux flow studies in superconductors using flux flow noise techniques. Progress report, April 1, 1977--December 17, 1977

Description: A model has been developed for the flux flow state in type II superconductors in which flux motion is interrupted by local interactions between pinning centers and moving fluxoids. This model allows us to predict the functional forms for the flux flow noise power spectrum and for the dc voltage-current characteristics. Experimental results conform quite closely to the predictions of this model. Measurements of noise spectra, voltage-current characteristics, and volume pinning force curves have … more
Date: December 1, 1977
Creator: Joiner, W.C.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Kinetic study of the formation of the superconducting A15 phase in the Nb-Al-Si system

Description: So far, aluminum-containing superconductors showed excellent critical fields and temperatures. Powder Metallurgy shows the most promise in producing these particular kinds of superconductors in the near future. The scope of this research is to apply a kinetic study to observe the behavior of the Nb(Al,Si) system at elevated temperatures. From such observations, an optimized method of obtaining the A15 superconducting phase can be achieved. This study has resulted in a two step heat treatment to… more
Date: December 1, 1978
Creator: Binh-Phung
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ion implantation and laser annealing of high T/sub c/ superconducting materials

Description: The materials investigated consisted of thin films of Nb-Ge, V-Si, Nb-N, Nb-C-N and Nb-Ir prepared by evaporation, sputtering or CVD onto substrates of alumina, sapphire or polycrystalline Hastelloy B. Single crystals of Nb/sub 3/Ir, NbN, V/sub 3/Si and V/sub 3/Ge were also studied and some laser annealing results will be presented. Laser annealing was performed in air using a Q-switched, (15 x 10/sup -9/ sec duration), Ruby laser with energy densities ranging from 0.1 to 10 J/cm/sup 2/. Single… more
Date: December 1, 1979
Creator: Appleton, B. R.; White, C. W.; Stritzker, B.; Meyer, O.; Gavaler, J. R.; Braginski, A. I. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Hierarchy of multiple many-body interaction scales in high-temperature superconductors

Description: To date, angle-resolved photoemission spectroscopy has been successful in identifying energy scales of the many-body interactions in correlated materials, focused on binding energies of up to a few hundred meV below the Fermi energy. Here, at higher energy scale, we present improved experimental data from four families of high-T{sub c} superconductors over a wide doping range that reveal a hierarchy of many-body interaction scales focused on: the low energy anomaly ('kink') of 0.03-0.09eV, a hi… more
Date: December 21, 2006
Creator: Hussain, Zahid; Meevasana, W.; Zhou, X. J.; Sahrakorpi, S.; Lee, W. S.; Yang, W. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design, production and first commissioning results of the electrical feedboxes of the LHC

Description: A total of 44 CERN designed cryogenic electrical feedboxes are needed to power the LHC superconducting magnets. The feedboxes include more than 1000 superconducting circuits fed by high temperature superconductor and conventional current leads ranging from 120 A to 13 kA. In addition to providing the electrical current to the superconducting circuits, they also ensure specific mechanical and cryogenic functions for the LHC. The paper focuses on the main design aspects and related production ope… more
Date: December 1, 2007
Creator: Perin, A.; Atieh, S.; Benda, V.; Bertarelli, A.; Bouillot, A.; Brodzinski, K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of Twist Pitch in the Strands on the Saturation and Losses in the Nb3Sn Strands for the ITER TF CICC

Description: ITER TF coils will see a significant longitudinal magnetic field in the event of the plasma disruption. This abrupt change of magnetic fields results in the appearance of an additional electrical field in the strands. The mechanism of this electrical field is the induced currents that expel the flux from the strands. This effect was known since the late 1970's [1-3] and most of the details necessary for the analyses given in this report are presented in [4]. Let's assume for simplicity a zero t… more
Date: December 6, 2007
Creator: Martovetsky, N. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Acquisition of Single Crystal Growth and Characterization Equipment

Description: Final Report for DOE Grant No. DE-FG02-04ER46178 'Acquisition of Single Crystal Growth and Characterization Equipment'. There is growing concern in the condensed matter community that the need for quality crystal growth and materials preparation laboratories is not being met in the United States. It has been suggested that there are too many researchers performing measurements on too few materials. As a result, many user facilities are not being used optimally. The number of proficient crystal … more
Date: December 9, 2008
Creator: Maple, M. Brian & Zocco, Diego A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Positron 2D-ACAR experiments and electron-positron momentum density in YBa sub 2 Cu sub 3 O sub 7-x

Description: We discuss positron annihilation (2D-ACAR) measurements in the C- projection on an untwinned metallic single crystal of YBa{sub 2}Cu{sub 3}O{sub 7-x} as a function of temperature, for five temperatures ranging from 30K to 300K. The measured 2D-ACAR intensities are interpreted in terms of the electron-positron momentum density obtained within the KKR-band theory framework. The temperature dependence of the 2D-ACAR spectra is used to extract a background corrected'' experimental spectrum which is… more
Date: December 1, 1991
Creator: Smedskjaer, L. C.; Welp, U.; Fang, Y.; Bailey, K. G. & Bansil, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A two-dimensional ACAR study of untwinned YBa sub 2 Cu sub 3 O sub 7-x

Description: We have carried out 2D-ACAR measurements on an untwinned single crystal of YBa{sub 2}Cu{sub 3}O{sub 7-x} as a function of temperature, for five temperatures ranging from 30K to 300K. We show that these temperature dependent 2D-ACAR spectra can be described to a good approximation as a superposition of two temperature independent spectra with temperature dependent weighting factors. We show further how the data can be used to correct for the background'' in the experimental spectrum. Such a back… more
Date: December 1, 1991
Creator: Smedskjaer, L.C. (Argonne National Lab., IL (United States)) & Bansil, A. (Northwestern Univ., Evanston, IL (United States). Dept. of Physics)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Grain boundary diffusion in oriented Ni sub 3 Al bicrystals containing boron

Description: The present research program entitled Grain Boundary Diffusion in Oriented Ni{sub 3}Al Bicrystals Containing Boron'' was granted to Lehigh University for a period of three years (September 1, 1986 to August 31, 1989). The work on grain boundary diffusion in Ni{sub 3}Al was partially completed. On the other hand, a number of new properties have been explored. Some additional efforts have been made on diffusion in newly discovered oxide superconductors.
Date: December 20, 1990
Creator: Chou, Y.T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Momentum density and 2D-ACAR experiments in YBa sub 2 Cu sub 3 O sub 7

Description: We compare measured c-projected 2D-ACAR spectrum from an untwinned single crystal of YBa{sub 2}Cu{sub 3}O{sub 7-x} with the corresponding band theory predictions. Many different one-dimensional sections through the spectrum are considered, together with the characteristic amplitudes and shapes of the spectral anisotropies, with a focus on identifying and delineating Fermi surface signatures in the spectra. The positron data clearly show several distinct features of the ridge Fermi surface predi… more
Date: December 1, 1991
Creator: Bansil, A. (Northeastern Univ., Boston, MA (United States). Dept. of Physics) & Smedskjaer, L.C. (Argonne National Lab., IL (United States))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Debye temperature of YBa sub 2 Cu sub 3 O sub 7-. delta. and its dependence on the volume fraction of superconductivity

Description: Specific-heat measurements, on polycrystalline samples of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, YBCO, have shown sample-to-sample variations in the volume fraction of superconductivity, f{sub s}, which is correlated with the concentration of Cu{sup 2+} magnetic moments in the YBCO lattice. At low temperatures the lattice specific heat also varies with f{sub s}, but these variations do not persist above {approximately}20K. The low-temperature data show that {Theta}{sub 0}{sup {minus}3} varies lin… more
Date: December 1, 1991
Creator: Fisher, R. A.; Phillips, N. E. (Lawrence Berkeley Lab., CA (United States)) & Gordon, J. E. (Lawrence Berkeley Lab., CA (United States) Amherst Coll., MA (United States). Dept. of Physics)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

New Al5 multifilamentary superconductor based on the niobium--aluminum--silicon system

Description: Based on Powder Metallurgy techniques, a process to fabricate Nb-Nb/sub 3/(Al,Si) multifilamentary superconducting wire has been developed. Optimum sintering and infiltration parameters are listed and the methods of mechanical reduction to wire form are described. Preliminary data indicate that diffusion reaction temperatures as low as 850/sup 0/C form the A15 superconducting compound Nb/sub 3/(Al,Si).
Date: December 1, 1977
Creator: Quinn, G.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Submillimeter and microwave residual losses in epitaxial films of Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O

Description: We have used a novel bolometric technique and a resonant technique to obtain accurate submillimeter and microwave residual loss data for epitaxial thin films of YBa[sub 2]Cu[sub 3]O[sub 7], Tl[sub 2]Ca[sub 2]Ba[sub 2]Cu[sub 3]O[sub 10] and Tl[sub 2]CaBa[sub 2]Cu[sub 2]O[sub 8]. For all films we obtain good agreement between the submillimeter and microwave data, with the residual losses in both the Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O films scaling approximately as frequency squared below [approximately]… more
Date: December 1, 1992
Creator: Miller, D.; Richards, P. L.; Eom, C. B.; Geballe, T. H.; Garrison, S. M.; Newman, N. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Study to assess the feasibility of scaling up the powder metallurgy approach for the fabrication of commercial Nb/sub 3/Sn filamentary superconductors

Description: A preliminary assessment was made of the feasibility of scaling up the laboratory techniques of making filamentary Nb/sub 3/Sn superconductors using powder metallurgy to commercial fabrication process. The purpose of the effort is divided into two tasks. The first one is to demonstrate that sintered niobium rods infiltrated with tin can be reduced in area of approximately 10/sup 4/. The second task pertains to the extrusion by conventional manner a copper billet containing several sintered rods… more
Date: December 9, 1977
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Short-term effects of intratracheal installations of yttrium barium copper oxide

Description: Inhalation exposures to the new high-temperature ({Tc}) superconductor (SC) materials can occur during manufacturing and fabrication processes. In this exploratory study, we examined the pulmonary response to the deposition of an yttrium barium copper oxide SC powder. Groups of Sprague-Dawley rats were intratracheally instilled with either 10 mg or 20 mg of SC in phosphate-buffered saline (PBS) or with PBS only. The animals were sacrificed 60 days later for histopathologic assessments of their … more
Date: December 1, 1990
Creator: London, J. E.; Newkirk, L. R. & Lehnert, B. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Dependence of stability of metastable superconductors on copper fraction

Description: The stability of composite superconductors operating in the metastable regime depends upon such factors as matrix resistivity, cooled surface dimensions, fraction of critical current, and volume fraction of stabilizer. By assuming constant thermophysical properties, we developed analytic expressions for the energy and voltage of the minimum propagating zone (MPZ). With other factors held constant, these expressions have been used to predict composite superconductor stability as a function of co… more
Date: December 1, 1980
Creator: Elrod, S. A.; Lue, J. W.; Miller, J. R. & Dresner, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Oxygen stoichiometry and its influence on superconductivity in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x}

Description: Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x} (2212) was synthesized from freeze-dried precursors. The oxygen content of 2212 was determined as a function of temperature and oxygen partial pressure and the variation of Tc with oxygen content was determined. It was found that 2212 without excess oxygen (x = 0) is superconducting. This points to the role of the (Bi-O){sub {infinity}} layers as a source for holes in 2212. Four probe resistivity measurements were also performed on 2212. The nature of oxy… more
Date: December 31, 1994
Creator: Krishnaraj, P.; Lelovic, M.; Eror, N. G. & Balachandran, U.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neutron scattering studies of magnetism in the high-Tc materials

Description: In this paper, I shall attempt to review what has been learned about magnetism in the high-{Tc} family of compounds using neutron scattering techniques. Whether or not it is true that magnetic effects are involved in an essential way in the mechanism for superconductivity in these materials (a point which has not yet been firmly established), they offer fascinating examples for the study of magnetism for its own sake, being realizations of spin {1/2} 2D quantum antiferromagnets. Further, the ra… more
Date: December 31, 1990
Creator: Sinha, S. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Microstructure and composition of electromagnetically-characterized YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} grain boundaries

Description: The electrical character (flux-pinning, Josephson junction, or resistive) of the grain boundaries in approximately twenty flux-grown YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} bicrystals was determined in previous studies. A selection of these same bicrystals now have been thinned for study by transmission and scanning transmission electron microscopy. High-spatial resolution imaging and analytical techniques reveal microstructural differences among these boundaries that are consistent with thei… more
Date: December 1, 1991
Creator: Babcock, S. E.; Zhang, Na; Cai, Xue Yu; Larbalestier, D. C.; Gao, Yufei; Merkle, K. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Syntheses and properties of {kappa}-phase organic superconductors

Description: The syntheses and physical properties of {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]X (X=Br and Cl) are summarized. The {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br salt is the highest {Tc} radical-cation based ambient pressure organic superconductor ({Tc}=11.6 K), and the {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl salt becomes a superconductor at even higher {Tc} under 0.3 kbar hydrostatic pressure ({Tc}=12.8 K). The similarities and differences between {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br and {kappa}-(ET){sub 2… more
Date: December 31, 1991
Creator: Wang, H. H.; Carlson, K. D.; Geiser, U.; Kini, A. M.; Schultz, A. J.; Williams, J. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen