Annealing Effects on Properties of High Tc YBa2Cu3O7−x Ceramics

1987 ◽  
Vol 99 ◽  
Author(s):  
Shin-Guang Shyu ◽  
R. F. Louh ◽  
R. C. Buchanan
Keyword(s):  
Superconducting Phase ◽  
Superconducting Properties ◽  
High Tc ◽  
X Ray ◽  
Heat Treated ◽  
Annealing Effects ◽  
Overall Resistance

ABSTRACTHigh Tc superconducting YBa2Cu3O7−x ceramics were prepared from the appropriate oxide constituents and heat treated under various conditions to determine the effects of annealing on superconducting properties. Sintered samples (900–920°C) were air cooled at 5°/min followed by annealing in oxygen or air at 500°C/12 hr. Resistance measurements, SQUID, SEM, and x-ray analysis were used to characterize the samples, which were of 38% porosity. Results showed all samples to be superconducting with TC(O) 84K. Superconducting properties of the air and oxygen annealed samples were equivalent but showed lower overall resistance and 30% higher superconducting phase (30 to 70 K) compared to the air cooled samples.

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.

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.

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.

EXAFS Study of Annealing Effects on Mg65Cu25Gd10 Metallic Glass

2007 ◽  
Vol 546-549 ◽  
pp. 477-480
Author(s):  
Guo Qiang Li ◽  
Li Jing Zheng ◽  
Z.F. Zhang ◽  
Huan Xi Li ◽  
M.F. Hashmi ◽  
...  
Keyword(s):  
Structural Changes ◽  
Local Environment ◽  
Test Machine ◽  
Compression Tests ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heat Treated ◽  
Annealing Effects ◽  
Exafs Study ◽  
X Ray Absorption

The effect of heat treatment on mechanical prosperities of Mg65Cu25Gd10 glass has been studied in this paper. The thermal stability and the structure of as-spun and heat treated Mg65Cu25Gd10 alloys were examined by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). The compression tests were performed using a computer controlled tensile test machine. Extended X-ray absorption fine structure (EXAFS) was applied to study the structural changes of Mg65Cu25Gd10 glass during annealing. Results showed that the decline of mechanical properties for Mg65Cu25Gd10 glass after annealing was closely related to the changes in local environment of Cu atoms and appearance of crystalline phases, and not the Gd local structure.

Effect of Oxygen Partial Pressure on Stability of High-Tc Phase in Sintered Bi-Pb-Sr-Ca-Cu-O Superconductos

1989 ◽  
Vol 169 ◽  
Author(s):  
H.K. Lee ◽  
K.W. Lee ◽  
D.H. Ha ◽  
J.C. Park
Keyword(s):  
Phase Transformation ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Superconducting Phase ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
High Tc Phase ◽  
Effect Of Oxygen

AbstractThe effect of oxygen partial pressure on stability of high-Tc phase in Bi-Pb-Sr-Ca-Cu-O system has been investigated using x-ray diffraction, resistivity and a.c. susceptibility measurements. It was found that part of the high-Tc phase in Bi-Pb-Sr-Ca-Cu-O system was transformed into the low-Tc phase (80 K) and insulating phases by heating in the temperature range 600 C to 880°C in O2 of one atmosphere. The original high-Tc phase was restored upon retreatment in a low oxygen partial pressure of 0.1 atmosphere. The reversible superconducting phase transformation is discussed in conjunction with the formation mechanism of the high-Tc phase in Bi-Pb-Sr-Ca-Cu-O system.

Annealing effects on molecular structures and physical properties of side-by-side conjugate fibers

2011 ◽  
Vol 81 (19) ◽  
pp. 2065-2071
Author(s):  
Tae Hwan Oh ◽  
Sung Soo Han ◽  
Won Seok Lyoo ◽  
Myung Seob Khil
Keyword(s):  
Physical Properties ◽  
Ethylene Terephthalate ◽  
Annealing Temperature ◽  
Molecular Structures ◽  
Thermal Shrinkage ◽  
X Ray ◽  
Poly Ethylene Terephthalate ◽  
Heat Treated ◽  
Annealing Effects ◽  
Poly Ethylene

Poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) side-by-side conjugate fibers were heat-treated to investigate the effects of annealing on structure development and physical properties. The effects of annealing temperature and time were observed. Even though the drawn conjugate fibers were sufficiently drawn, X-ray profiles showed that the molecular orientation was insufficient. After annealing for more than 1 hour at 180°C, PET and PTT crystal structures developed sufficiently. Crimp contraction decreased from 29% to 22.6% by annealing due to the development of the crystalline structure of the annealed PTT part. Decrease in a shrinkage difference between PET and PTT leads to a decrease in crimp contraction. Thermal shrinkage was also reduced from 11.0% to 1.8% by annealing.

Epitaxial Films of High Tc Oxide Superconductors Y1Ba2Cu3O7 Grown on SrTiO3 by Molecular Beam Epitaxy

1987 ◽  
Vol 99 ◽  
Author(s):  
J. Kwo ◽  
T. C. Hsieh ◽  
M. Hong ◽  
R. M. Fleming ◽  
S. H. Liou ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Film Plane ◽  
Epitaxial Films ◽  
Superconducting Phase ◽  
Oxide Superconductors ◽  
High Tc ◽  
Rocking Curve ◽  
X Ray ◽  
High Degree

ABSTRACTOrientation ordered high-Tc oxide films of Y1Ba2Cu3O7 were prepared by molecular beam epitaxy on SrTiO3 substrates. A combination of effusion cells and e-beam evaporators was used with the addition of an oxygen jet. The superconducting phase is formed by further O2 anneal at temperatures ≥800° C. For SrTiO3 (100), the Y1Ba2Cu3O7 films grow in the orientation of either the c-axis or the a-axis perpendicular to the film plane. Films with predominant “c⊥” orientation exhibit a high degree of crystalline order with a rocking curve 0.3° wide. The Jc is about two times higher than those with the “a⊥” orientation of a comparable Tc (R=0). For a typical film of 9000Å thickness, a Tc (R=O) of 87K, and a Jc of 7 × 104 A/cm2 at 77K were reproducibly achieved. For SrTiO3 (110), X-ray showed twinning of (110) and (103) orientations in Y1Ba2Cu3O7, thus precluding the observation of anisotropy expected for the in-plane axes of [001] and [110].

Structure, Composition and Superconductivity of High Tc Tl–Ba–Ca–Cu–O System

1989 ◽  
Vol 156 ◽  
Author(s):  
Yasuhiko Syono ◽  
Masae Kikuchi ◽  
Satoru Nakajima ◽  
Teruo Suzuki ◽  
Takeo Oku ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Probe ◽  
Magnetic Measurements ◽  
Chemical Compositions ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
Critical Temperatures ◽  
High Tc ◽  
X Ray ◽  
Transmission Electron

ABSTRACTBulk high Tc superconductors of Tl2Ba2Can−1CunO2n+4 (n=1−4) and TlBa2Can−1CunO2n+3 (n=2−5) were synthesized, and their structures, chemical compositions and superconducting properties were studied by means of X-ray powder diffraction, electron probe microanalysis, transmission electron microscopy, and electrical and magnetic measurements. Superconducting critical temperatures are discussed in terms of average Cu valence and Cu-O bond length within the plane which vary with the number of Cu layers.

Superconducting Properties of Bi-Sr-Ca-Cu-O Crystallized Glass

1999 ◽  
Vol 13 (09n10) ◽  
pp. 985-989
Author(s):  
S. Chudinov ◽  
S. Stizza ◽  
B. Kościelska ◽  
L. Murawski ◽  
W. Sadowski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Glass Ceramics ◽  
Superconducting Phase ◽  
Superconducting Transition ◽  
Resistive Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
X Ray ◽  
Quenching Method

This paper reports the crystallization and superconducting properties of Bi 4 Sr 3 Ca 3 Cu 4 O x glass-ceramics. The glass was prepared using the conventional melt-quenching method. X-ray diffraction pattern has shown that the annealing at temperature of 800°C converted the glass into glass-ceramics with Bi 2 Sr 2 CaCu 2 O x superconducting phase (2212-phase). The superconducing transition exhibits the change in the slope that is characteristic for two different superconducting phases. It is observed that T c (zero) increases from 20 K to 80 K with increasing time of annealing. The influence of magnetic field on the superconducting transition has been investigated. Our studies revealed a remarkable broadening of the resistive transition as a function of temperature with increasing field. The temperature width ( T c-T) of the transition for both phases increases with magnetic field according to Tinkham model.

The Effect of Sheath Materials on the Superconductivity of MgB2

2001 ◽  
Vol 689 ◽  
Author(s):  
W. Zhu ◽  
D. R. Watson ◽  
J. R. Cave
Keyword(s):  
Palladium Alloy ◽  
Processing Conditions ◽  
Squid Magnetometry ◽  
Superconducting Properties ◽  
Critical Temperatures ◽  
X Ray ◽  
Heat Treated ◽  
Magnetization Data ◽  
Silver Palladium ◽  
Powder In Tube

ABSTRACTInconel, tantalum and a silver-palladium alloy were used to fabricate MgB2tapes. The tapes, made by the Powder In Tube (PIT) method, were heat-treated at 800°C and 900°C in 1 atmosphere of flowing argon. The microstructure and phase composition of the tapes were examined by Scanning Electron Microscopy (SEM) and X-Ray Diffractometry (XRD). Critical temperatures (Tc) and magnetization-applied magnetic field (M-H) curves were measured by SQUID magnetometry. It is found that between 800–900°C inconel and tantalum sheaths have no effect on the Tc,inductive of the material. However, under certain processing conditions, the silver-palladium sheath can decrease the Tcor destroy the superconductivity completely. The inconel sheathed tape was found to have better superconducting properties than the tantalum and silver-palladium sheathed tapes. Consistency checks have been applied to verify the validity of the Bean Model in obtaining the critical current density (Jc) from magnetization data. The inconel sheathed tape is estimated to have a magnetization Jc(5K, ∼0.5 T) of 1.4 × 105A/cm2.

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