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.

Effect of Oxidizing Atmosphere on Superconductivity in RBa2Cu3−xMxOz

1987 ◽  
Vol 99 ◽  
Author(s):  
David A. Robinsonem ◽  
Abbot Maginnis ◽  
A. Morrobel-Sosa ◽  
Chester Alexander ◽  
C. Asavaroengchai ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electrical Resistance ◽  
Single Phase ◽  
Analysis Data ◽  
Nominal Composition ◽  
Superconducting Properties ◽  
Metal Substitution ◽  
Critical Temperatures ◽  
X Ray ◽  
Heat Treated

ABSTRACTThe dependence of the superconducting properties of RBa2Cu3−xMxOz (R = Y, Gd, M = Cr, Mn, Fe, Co, Ni, and x = 0.0, 0.025, 0.05, 0.1, 1.0, 3.0) on the oxidizing environment used during the processing (sintering/annealing) of these materials has been investigated. Samples of nominal composition, YBa2Cu3Oz, were prepared from the same starting materials and subjected to two different controlled heat treatments, under both controlled oxygen and ozone atmospheres. Measurements of ac electrical resistance versus temperature indicate that the critical temperatures are increased, and the widths of the superconducting transitions are narrowed for identically heat-treated samples when processed under ozone atmosphere rather than under an oxygen environment. Thermogravimetric analysis data indicate this trend to be correlated with increased oxygen content and thermal stability. This effect is also observable for materials with metal substitution for Cu, although the measured Tc's are generally lower for increased values of x. X-ray powder diffraction analysis showed the materials to be mostly single phase.

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.

scholarly journals Effect of K Substitutions on Structural and Superconducting Properties in Bi1.6Pb0.4Sr2-xKxCa2Cu3O10+ Compounds

2019 ◽  
Vol 35 (2) ◽  
Author(s):  
Tran Hai Duc ◽  
Pham The An ◽  
Do Thi Kim Anh ◽  
Vu Hoang Linh ◽  
Pham Hoang Ha ◽  
...  
Keyword(s):  
Solid State Reaction Method ◽  
Magnetization Curves ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Residual Resistance ◽  
X Ray ◽  
Magnetization Data ◽  
Temperature Dependences ◽  
Residual Resistance Ratio ◽  
Additional Point

Abstract: Effect of K substitutions on structural and superconducting properties in Bi-Pb-Sr-Ca-Cu-O (BPSCCO) system has been investigated. Bulk Bi1.6Pb0.4Sr2-xKxCa2Cu3O10+d (where x = 0.00; 0.04; 0.08 and 0.1) samples were fabricated by using the solid-state reaction method. Structural properties of the samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurement. All samples showed co-existence of  Bi-2223 and Bi-2212 superconducting phases. Interestingly, a formation of the Bi-2223 was decelerated and that of the Bi-2212 was accelerated with increasing K content (x). Superconducting properties of the samples were characterized by using temperature dependences of resistance and field dependences of magnetization data. Both onset and offset transition temperatures were found to decrease, those were correlated to the decreases in residual resistance ratio (RRR). The 65 K magnetization curves of K- substituted samples were enlarged in comparison with that of the pure one. Enlargements of the magnetization curves were possibly attributed to the appearance of additional point-like defects generated by substitutions of K into Sr site. Keywords: BPSCCO, substitutions, flux pinning, defects.

Structural and superconducting properties of Nb3Sn film for superconducting radio-frequency cavities synthesized via bronze route

2021 ◽  
pp. 2151030
Author(s):  
Feng Pan ◽  
Ming Lu ◽  
Andong Wu ◽  
Qingwei Chu ◽  
Ziwei Lu ◽  
...  
Keyword(s):  
Thin Film ◽  
Radio Frequency ◽  
Ex Situ ◽  
Tubular Furnace ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Critical Temperatures ◽  
X Ray ◽  
Superconducting Radio Frequency ◽  
A New Technique

Superconducting Nb3Sn films were synthesized via the ex-situ annealing of Nb-coated bronze precursors. The precursors were prepared by sputtering 2 [Formula: see text]m of niobium film onto a bronze surface. The annealing was conducted in a vacuum tubular furnace at a temperature not higher than 700[Formula: see text]C. By changing the annealing time and temperature, a series of Nb3Sn samples with critical temperatures ([Formula: see text] > 16 K were obtained. X-ray diffraction confirmed the existence of the cubic Nb3Sn phase (A15 structure), whereas magnetic moment measurements indicated that critical temperature of the studied samples ranged from 16.2 to 16.5 K. Therefore, this study explores a new technique appropriate for creating copper-based Nb3Sn thin-film-coated superconducting radio-frequency (TFSRF) cavities.

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.

Effect of Co Doping on the Superconducting Properties of Overdoped (Lu0.8Ca0.2)Ba2Cu3Oz

2006 ◽  
Vol 47 ◽  
pp. 108-112 ◽  
Author(s):  
Ho Keun Lee
Keyword(s):  
Thermoelectric Power ◽  
Room Temperature ◽  
Oxygen Depletion ◽  
Thermal Treatments ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Heat Treated ◽  
Power Measurements

The effect of Co-doping and thermal treatments on the superconducting properties of the heavily overdoped (Lu0.8Ca0.2)Ba2Cu3Oz has been investigated by X-ray diffraction, resistivity and thermoelectric power measurements. A comparative analysis of the resistivity and thermoelectric power of the (Lu0.8Ca0.2)Ba2(Cu3-xCox)Oz and the heat-treated Co-free (Lu0.8Ca0.2)Ba2Cu3Oz reveals that, in the overdoped region, the hole carriers reduced by the Co doping and by the oxygen depletion play a very similar role in the superconducting properties. As a result, a nearly common inverted parabolic correlation is observed between Tc and the planar carrier concentration determined from the room-temperature thermoelectric power measurements.

Effect of heat treatment time and temperature on the properties of YBa2Cu3O7−x

1989 ◽  
Vol 4 (5) ◽  
pp. 1093-1098 ◽  
Author(s):  
Ira Bloom ◽  
B. S. Tani ◽  
M. C. Hash ◽  
Donglu Shi ◽  
M. A. Patel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Properties ◽  
Treatment Time ◽  
The Other ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Rich Material ◽  
Scanning Electron

Two YBa2Cu3O7−x powders were investigated: one was nearly stoichiometric, and the other, CuO-rich. After being sintered at 950 °C, samples from both powders were heat-treated in oxygen at 845, 860, and 910 °C for up to 10 days. The samples were characterized by differential thermal analysis, x-ray diffraction, optical and scanning electron microscopy, iodometric titrations, and measurement of their superconducting properties (electrical resistivity, critical temperature, and critical current density). The electrical properties of the nearly stoichiometric material improved with time at all temperatures. On the other hand, the electrical properties of the CuO-rich material deteriorated with temperature, possibly owing to problems associated with grain growth at 910 °C.

scholarly journals Design and Optimization of Processing Conditions for a Recent Quenched and Partitioned Steel

2021 ◽  
Author(s):  
Eman Hassan El-Shenawy ◽  
Hoda Nasr El-Din Hedia ◽  
Mai Mohamed Kama-El-Din ◽  
Hoda Refaiy Badwy
Keyword(s):  
Heat Treatment ◽  
Tensile Properties ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Testing Machine ◽  
High Strength ◽  
Processing Conditions ◽  
Critical Temperatures ◽  
Tensile Testing Machine ◽  
Heat Treated

Q&P steels as a "Third Generation" of (AHSS) exhibit excellent tensile properties, which enable producing lightweight sections for the automotive industry and at the same time keep safety requirements. This research aims to predict the proper processing conditions for developing ultra-high-strength Q&P steel with a novel chemical composition of 0.37 C-3.65 Mn- 0.65Si- 0.87 Al- 1.5 Ni- 0.05P, wt. %. To design and optimize proper heat treatment conditions, the phase diagram, CCT curve, and critical temperatures of these alloys were first implemented using THERMO-CALC and JMATE PRO software and Gleeble 3500 machine. The heat treatment process included full austenitization, then quenching at 120°C followed by partitioning at 450°C for different times. The tensile properties, microstructure, and retained austenite volume fraction of heat-treated steel was studied at room temperature by tensile testing machine, optical microscope, and XRD. The finding summarized that partitioning of this steel for 100 s during processing had developed Q&P steel with ultra-high-strength of 1104 MPa with maximum total elongation and strength elongation balance 8.1 % and 8932 MPa %, respectively. The optical micrograph showed that heat-treated specimens at different partitioning times have had a microstructure of tempered martensite, carbide free bainite, and retained austenite. Besides, the retained austenite volume fraction has decreased with increasing partitioning time, which may be due to carbide precipitation during partitioning.

Superconducting properties of mixtures of Y1Ba2Cu3O9−x and Y1.8Ba0.2Cu1O5−y

1988 ◽  
Vol 3 (6) ◽  
pp. 1297-1303 ◽  
Author(s):  
X. W. Wang ◽  
H. S. Kwok ◽  
L. Shi ◽  
J. P. Zheng ◽  
P. Mattocks ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Meissner Effect ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray ◽  
Heat Treated

The superconducting properties of heat-treated mixtures of Y1Ba2Cu3O9−x (A) and Y1.8Ba0.2Cu1O5−y (B) have been studied. As the concentration of B increases, the Meissner effect decreases, while the resistance jump near the superconducting transition increases. When the fraction of B approaches about 0.5, the superconducting transition disappears. Four different phases are identified in the mixture from the x-ray spectra, i.e., Y1Ba2Cu3O9−x, Y2Ba1Cu1O5–z, Y2Cu2O5, and Y2O3. The results agree well with the published phase diagram of this system.

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.

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