Preparation of Bi-Pb-Sr-Ca-Cu-O Superconductor By Thermal Decomposition of an Edta Colloid

1990 ◽  
Vol 180 ◽  
Author(s):  
H.S. Koo ◽  
C.K. Chiang ◽  
Y.T. Huang ◽  
G.C. Tu
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Solid State Reactions ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
High Tc ◽  
X Ray ◽  
Metal Nitrates ◽  
Zero Resistance

ABSTRACTHigh-Tc superconducting Bi-Pb-Sr-Ca-Cu oxide with zero resistance temperature at above lOOK has been synthesized via the use of ethylenediamine-tetra-acetate(EDTA) colloid and corresponding metal nitrates. Remarkable sinterability of the precursor requires shorter time to achieve superconducting phases than conventional solid-state reactions. Superconducting properties were measured electrically and magnetically. The thermal decomposition, X-ray diffraction and microstructural characteristics of the precursor and the sintered samples were also discussed.

SUPERCONDUCTING PROPERTIES OF THE HIGH Tc SUPERCONDUCTING Er-Ba-Cu-O COMPOUND

1989 ◽  
Vol 03 (03) ◽  
pp. 441-444 ◽  
Author(s):  
S. M. M. R. NAQVI ◽  
FIROZ AHMAD ◽  
JAWAID ALAM ◽  
SHARFUDDIN AHMAD
Keyword(s):  
Superconducting Phase ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Zero Resistance ◽  
Two Phases

Two batches of Er-Ba-Cu-O superconductors have been prepared. The zero resistance temperature is 86 K with T c onsets at 99 K and 92 K respectively. Susceptibility measurements show superconducting phase at LN 2. X-ray diffraction results indicates two phases, the superconducting being the major one.

TEM studies of solid-state reactions in sputter-deposited Nb/Al multilayer thin films

1996 ◽  
Vol 54 ◽  
pp. 1020-1021
Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Stoichiometric Composition ◽  
Analytical Electron Microscopy ◽  
Grain Structure ◽  
Solid State Reactions ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputter Deposited

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.

STUDY OF THE DEPENDENCE OF HIGH Tc ON VARIOUS SINTERING TEMPERATURES FOR Bi-Pb-Sr-Ca-Cu-O SUPERCONDUCTORS

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1635-1638
Author(s):  
S.M. M.R. NAQVI ◽  
A.A. QIDWAI ◽  
S.M. ZIA-UL-HAQUE ◽  
FIROZ AHMAD ◽  
S.D.H. RIZVI ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Liquid Nitrogen ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Resistivity Measurements ◽  
Zero Resistance

Bi1.7-Pb0.3-Sr2-Ca2-Cu3-Ox superconducting samples were prepared at 855°C, 862 C, 870 C, and 882 C sintering temperatures respectively. All samples were sintered for 120 hours. The samples were then quenched in liquid nitrogen. The electrical resistivity measurements showed that the samples sintered at 870° C had the best Tc. For these samples the Tc onset was around 120 K and the zero resistance was obtained at 108 K. X-ray diffraction studies showed that the samples were multiphased.

EXPERIMENTAL STUDY OF THE HIGH Tc SUPERCONDUCTOR Y-Ba-Cu-O SYSTEM

1989 ◽  
Vol 03 (08) ◽  
pp. 661-664
Author(s):  
S.M.M.R. NAQVI ◽  
JAWAID ALAM ◽  
FIROZ AHMAD ◽  
MUSHEER HASAN KHAN
Keyword(s):  
Experimental Study ◽  
Superconducting Phase ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
High Tc Superconductor ◽  
Zero Resistance

Two batches of Y-Ba-Cu-O superconductors have been prepared. The zero resistance temperature is 90 K with Tc onset at 93 K and 95 K, respectively. Susceptibility measurements show superconducting phase at LN2. X-ray diffraction results indicates single phases.

X-Ray Diffraction Studies on Shock Modified Y Ba2 Cu3 O7 Superconductors

1988 ◽  
Vol 32 ◽  
pp. 429-436
Author(s):  
Lynn E. Lowry ◽  
Daniel D. Lawson ◽  
Wayne M. Phillips
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Shock Compression ◽  
Ceramic Materials ◽  
Copper Matrix ◽  
Fabrication Technique ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Induced Defects

Y.Ba2Cu3O7, a high TC superconductor powder, was shock compacted and explosively welded inside a copper matrix using the explosive fabrication methods described by Murr, Hare and Eror. The shock compression fabrication technique provides the ability to process the superconductor powders into useable structures that will minimize environmental degradation and will not negatively affect the physical or mechanical properties. Additionally, the introduction of shock induced defects are known to increase solid-state reactivity in ceramic materials. For this reason, shock compression fabrication of the superconductor/copper system offers the possibility of enhancing the superconducting properties of the YBa2Cu3O7 powders.

Relation of starting precursors to the resulting high-Tc phases in the Pb and Sb doped Bi—Sr—Ca—Cu—O system

1994 ◽  
Vol 9 (2) ◽  
pp. 292-296 ◽  
Author(s):  
F. Constantinescu ◽  
R. Holiastou ◽  
D. Niarchos ◽  
G.K. Nicolaides ◽  
F. Vasiliu ◽  
...  
Keyword(s):  
Ac Susceptibility ◽  
Partial Substitution ◽  
Dc Resistivity ◽  
Squid Magnetometry ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Phase Sample ◽  
Semiconducting Behavior

The introduction of more reactive precursors for Pb and Sr (oxalates), as well as Ca (citrate) and the use of a Bi nitrate decomposition route, has increased the percentage of the high-Tc (2223) phase in the Bi—Sr—Ca—Cu—O (BSCCO) system. Partial substitution of Bi(Pb) with Sb gives an almost single (2223) phase sample. In addition, a single (2212) phase sample is obtained when high purity Bi2O3 is used as a precursor, whereas Bi acetate leads to semiconducting behavior. The morphology of the samples is studied with a scanning electron microscope (SEM), the stoichiometry with energy-dispersive x-ray analysis (EDAX), and the structure with x-ray diffraction (XRD), while the superconducting properties are investigated by dc-resistivity, ac-susceptibility, and SQUID magnetometry techniques.

Solid-state reaction of Pt thin film with single-crystal (001) β–SiC

1994 ◽  
Vol 9 (3) ◽  
pp. 648-657 ◽  
Author(s):  
J.S. Chen ◽  
E. Kolawa ◽  
M-A. Nicolet ◽  
R.P. Ruiz ◽  
L. Baud ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Single Crystal ◽  
Atomic Scale ◽  
Solid State Reactions ◽  
Main Reaction ◽  
Main Reaction Product ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Interlayer

Thermally induced solid-state reactions between a 70 nm Pt film and a single-crystal (001) β-SiC substrate at temperatures from 300 °C to 1000 °C for various time durations are investigated by 2 MeV He backscattering spectrometry, x-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that Pt reacts with SiC at 500 °C. The product phase identified by x-ray diffraction is Pt3Si. At 600–900 °C, the main reaction product is Pt2Si, but the depth distribution of the Pt atoms changes with annealing temperature. When the sample is annealed at 1000 °C, the surface morphology deteriorates with the formation of some dendrite-like hillocks; both Pt2Si and PtSi are detected by x-ray diffraction. Samples annealed at 500–900 °C have a double-layer structure with a silicide surface layer and a carbon-silicide mixed layer below in contact with the substrate. The SiC—Pt interaction is resolved at an atomic scale with high-resolution electron microscopy. It is found that the grains of the sputtered Pt film first align themselves preferentially along an orientation of {111}Pt//{001}SiC without reaction between Pt and SiC. A thin amorphous interlayer then forms at 400 °C. At 450 °C, a new crystalline phase nucleates discretely at the Pt-interlayer interface and projects into or across the amorphous interlayer toward the SiC, while the undisturbed amorphous interlayer between the newly formed crystallites maintains its thickness. These nuclei grow extensively down into the substrate region at 500 °C, and the rest of the Pt film is converted to Pt3Si. Comparison between the thermal reaction of SiC-Pt and that of Si–Pt is discussed.

X-ray diffraction data for a distorted brockite and its solid state reactions with Na2CO3

1983 ◽  
Vol 93 (2) ◽  
pp. 433-440 ◽  
Author(s):  
M. Kizilyalli ◽  
D.S. Jones ◽  
N. Evi̇n ◽  
H. Göktürk
Keyword(s):  
Solid State ◽  
Diffraction Data ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
X Ray
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