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.

CHARACTERIZATION AND MICRO-RAMAN STUDIES OF Bi2−xPbxSr2Ca2Cu3O10+δ (0 ≤ x ≤ 0.6) SUPERCONDUCTOR

1994 ◽  
Vol 08 (10) ◽  
pp. 591-603
Author(s):  
U. SINHA ◽  
S. SATHAIAH ◽  
R. N. SONI ◽  
H. D. BIST ◽  
S. C. MATHUR ◽  
...  
Keyword(s):  
Ac Susceptibility ◽  
Solubility Limit ◽  
Dc Resistivity ◽  
Apical Oxygen ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray ◽  
Percentage Volume ◽  
Pb Substitution ◽  
Scanning Electron

The X-ray diffraction (XRD), ac susceptibility, dc resistivity, and scanning electron microscopy (SEM) measurements on Bi 2−x Pb x Sr 2 Ca 2 Cu 3 O 10+δ (x = 0.0, 0.2, 0.4, and 0.6) superconductors have been correlated with the Raman scattering studies. Remarkable increases in the transition temperature and percentage volume of high T c phase are found till x = 0.4. Raman spectra also reveal dramatic changes at x = 0.4 in the phonon modes at 625 and 460 cm −1 associated with oxygen vibrations in BiO plane and apical oxygen of CuO 5 pyramid, respectively. The observed changes have been attributed to the phenomenon of oxygen redistribution among various layers. Optimum solubility limit of Pb substitution is found to be x = 0.4.

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.

BISMUTH PARTIAL SUBSTITUTION EFFECT ON PROPERTIES OF THE Bi2Sr2Ca2Cu3OZ SYSTEM

2002 ◽  
Vol 16 (20) ◽  
pp. 769-774
Author(s):  
S. SIMON ◽  
R. V. F. TURCU ◽  
M. POP ◽  
Gh. BORODI
Keyword(s):  
Heat Treatment ◽  
Diffraction Analysis ◽  
Liquid Nitrogen ◽  
Substitution Effect ◽  
Liquid Nitrogen Temperature ◽  
Partial Substitution ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Static Susceptibility ◽  
X Ray

The effect of bismuth partial substitution by lead, cadmium or tin on the properties of the polycrystalline systems Bi 2-x M x Sr 2 Ca 2 Cu 3 O z (M = Pb, Cd or Sn) was investigated. The samples were obtained from amorphous precursors by heat treatment applied in several stages. X-ray diffraction analysis and static susceptibility measurements were carried out in order to characterize the structure and to check the superconducting properties of the investigated samples. Superconducting behavior above liquid nitrogen temperature was evidenced only for the partial substitution of Bi with x = 0.2 Pb and x = 0.1 Sn.

Effect of Ca2CuO3 excess on superconducting properties in the Bi–Pb–Sr–Ca–Cu–O system

1991 ◽  
Vol 6 (11) ◽  
pp. 2287-2290 ◽  
Author(s):  
H.K. Liu ◽  
S.X. Dou ◽  
S.J. Guo ◽  
K.E. Easterling ◽  
X.G. Li
Keyword(s):  
Critical Field ◽  
Pulse Magnetic Field ◽  
Ac Susceptibility ◽  
Upper Critical Field ◽  
Undoped Sample ◽  
Loss Peak ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature

The effect of excess Ca2CuO3 on the superconducting properties in the (Bi, Pb)2Sr2Ca2Cu3Oy, (2223) was investigated through the measurements of ac susceptibility, critical current density, and critical field. All the measurements have been performed on the samples that were identified by x-ray diffraction to consist of the mostly high Tc 2223 phase with varying amounts of excess Ca2CuO3. It was found that when the excess Ca2CuO3 is in the range 0.1 M to 0.3 M the loss peak of ac susceptibility appeared at higher temperature than that for an undoped sample, and the Jc showed a maximum at the excess Ca2CuO3 = 0.2 M, indicating that a proper amount of excess Ca2CuO3 enhanced the flux pinning. The upper critical field, Hc2, determined by using a pulse magnetic field showed a maximum at the excess Ca2CuO3 = 0.1 M, and increased linearly with decreasing temperature within the measurement regime.

scholarly journals Bi-based high Tc superconducting fibers by melt extraction

1992 ◽  
Vol 7 (9) ◽  
pp. 2365-2372
Author(s):  
J.J. Chang ◽  
G. Rudkowska ◽  
A. Zaluska ◽  
P. Rudkowski ◽  
J.O. Ström-Olsen ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Lattice Parameter ◽  
Squid Magnetometry ◽  
X Ray Diffraction ◽  
Initial Composition ◽  
Scanning Calorimetry ◽  
High Tc ◽  
X Ray ◽  
Melt Extraction ◽  
Bcc Phase

Bismuth-based high Tc superconductors have been prepared as fibers by a technique of melt extraction. As-made, the fibers are amorphous with diameters ranging from 0.7 μm to 100 μm and lengths of up to 5 cm. The fibers were subsequently transformed into high Tc superconductors by heat treatment in air. Superconducting transitions at 105 K and 82 K were measured in annealed fibers of initial composition Bi1.8Pb0.2Sr2Ca3Cu4Ox by SQUID magnetometry. The volume fractions of superconducting phases were estimated to have lower bounds of 30% for 2212 and 5% for 2223. The crystallization process has been studied by differential scanning calorimetry, electron microscopy, and x-ray diffraction. Crystallization involves first the formation of the Bi-2201 phase and a bcc phase with lattice parameter a = 0.425 nm before finally significant fractions of both the Bi-2212 and Bi-2223 phases are formed.

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.

Susceptibility Study of Site Selective Doped Fullerenes - K2RbC60, Rb3C60, K2CsC60, and Rb2CsC60

1994 ◽  
Vol 349 ◽  
Author(s):  
M. Baenitz ◽  
M. Heinze ◽  
K. Lüders ◽  
H. Werner ◽  
R. Schlögl
Keyword(s):  
Ac Susceptibility ◽  
Xrd Analysis ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Fcc Lattice ◽  
Doped Fullerenes ◽  
Susceptibility Study ◽  
Site Selective

ABSTRACTThe superconducting properties of several binary and ternary fullerene compounds are investigated by means of ac susceptibility technique. The susceptibility X = X'-iX” is observed as a function of temperature for different magnetic field amplitudes (0.01 G - 20 G). The samples are characterized by X-ray diffraction (XRD) analysis and the fcc-lattice constants a0 are determined. Furthermore the influence of the preparation procedure, especially the treatment of the C60 starting material on the superconducting properties is discussed.

Cerium Doped Bismuth Based High Tc Superconductor: Synthesis and Study of Superconducting Properties

2012 ◽  
Vol 510-511 ◽  
pp. 75-79
Author(s):  
M. Mubeen ◽  
M. Anis-ur-Rehman
Keyword(s):  
Chemical Method ◽  
Room Temperature ◽  
Dc Resistivity ◽  
Ceramic Superconductor ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Resistivity Measurements ◽  
Wet Chemical

High-Tcsuperconductivity has been an emerging field for researchers since its discovery. Bismith based superconductors commonly called BSCCO have great importance among the superconducting family. It is divided into three phases among them 2223 phase is highly studied in order to investigate its superconducting properties by substitution of different elements. We have studied the substitution of cerium (Ce) on calcium site of bismuth based Bi (Pb)Sr (Ba)-2223 high-Tcsuperconductor. The nominal compositions of Bi1.6Pb0.4Sr1.6Ba0.4(Ca1-xCex)2Cu3Oxceramic superconductor were prepared by wet chemical method. Stoichiometric amounts of Bi2O3, PbO, Sr (NO3)2, BaCO3, CaCO3, CuO and CeO2were used as starting materials. Structural analysis was done by X-ray diffraction (XRD) at room temperature and different parameters were calculated. DC resistivity measurements for the transition temperature of synthesized superconducting samples were taken by the standard four-probe method, apparatus for which was developed in our laboratory. It is observed that with the substitution of cerium on calcium site the single high-Tc2223 phase is obtained.

scholarly journals Superconducting Properties of the (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2 Ca2Cu3-x Nix O10+? System.

2011 ◽  
Vol 8 (2) ◽  
pp. 607-612 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Transition Temperature ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Superconducting Properties ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Sintering Time ◽  
Dominant Phase

The effect of substitution of Ni on Cu in (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2 Ca2Cu3-x Nix O10+? for (x=0,0.1….1,2,3) superconductor system and sintering time has been investigated .The samples were prepared by solid-state reaction methods. The results show that the optimum sintering temperature is equal to 850 ºC, and the sintering time is equal to 140 h. The highest transition temperature (Tc) obtained for (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2 Ca2Cu3-x NixO10+? composition was 113 with x=0.8 Phase analyses of the samples by X-ray diffraction (XRD) analysis showed an orthorhombic structure with a high Tc phases (2223) as a dominant phase and low Tc phase (2212) in addition to some impurity phases.

STRUCTURAL AND SUPERCONDUCTING PROPERTIES OF Bi4Sr3Ca3CuyOw AND Bi4Sr3Ca3Cu4−xMxOz(M=Fe, Cr AND Mn) GLASS CERAMICS

1995 ◽  
Vol 09 (04n05) ◽  
pp. 549-561 ◽  
Author(s):  
E. ZACHARIAS ◽  
R. SINGH
Keyword(s):  
Dopant Concentration ◽  
Ac Susceptibility ◽  
Glass Ceramics ◽  
Lattice Parameter ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Dopant Content ◽  
X Ray ◽  
Ceramic Superconductors

The synthesis of glass ceramic superconductors of Bi 4 Sr 3 Ca 3 Cu y O w(3≤y≤6) and Bi 4 Sr 3 Ca 3 Cu 4−x M x O z ( M=Fe , Cr , Mn and 0≤x≤0.2) compositions is reported. The 4334 sample is found to be the optimum composition to obtain Bi-2212 superconducting phase. X ray diffraction studies indicate that the solid solubility of 3d metal ions in the 4334 system is limited to x=0.05 in the case of Fe and Cr and x=0.1 in the case of Mn. A systematic decrease in Tc with increasing dopant concentration is observed from resistivity as well as AC susceptibility measurements. Tc depression rates, however, are found to differ for different dopants. XRD studies indicate the decrease in c lattice parameter with increase in dopant content. The systematics of the superconducting transition is discussed in view of Tc depression rates.

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