Influence of deposition rate on the properties of thick YBa2Cu3O7–δ films

1997 ◽  
Vol 12 (11) ◽  
pp. 2941-2946 ◽  
Author(s):  
S. R. Foltyn ◽  
E. J. Peterson ◽  
J. Y. Coulter ◽  
P. N. Arendt ◽  
Q. X. Jia ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Deposition Rate ◽  
Current Density ◽  
Oxygen Deficiency ◽  
Lattice Parameter ◽  
High Rate ◽  
Superconducting Transition ◽  
And Performance ◽  
Low Rate

To investigate potential limits to the rate at which high-quality YBa2Cu3O7–δ can be deposited, we have produced a series of 1 μm thick films by pulsed laser deposition on single-crystal SrTiO3 substrates at average rates ranging from 2 Å/s to 240 Å/s. The critical current density of low-rate films was over 2 MA/cm2 at 75 K, self field, but dropped linearly with rate to about 1 MA/cm2 at the upper end of the range. In addition, the superconducting transition temperature, resistivity above the transition, and performance in an applied magnetic field were all degraded by increasing the deposition rate. A change in c-axis lattice parameter suggests that possible causes for this degradation are oxygen deficiency or cation disorder with the latter being the more likely. Annealing high-rate films at 790 °C for as little as 20 min improved critical current density to within 20% of low-rate values, and resulted in dramatic improvements in other film properties as well.

Characterization of superconducting SmBa2Cu3O7 films grown by pulsed laser deposition

2002 ◽  
Vol 17 (10) ◽  
pp. 2599-2603 ◽  
Author(s):  
Q. X. Jia ◽  
S. R. Foltyn ◽  
J. Y. Coulter ◽  
J. F. Smith ◽  
M. P. Maley
Keyword(s):  
Transition Temperature ◽  
Critical Current Density ◽  
Pulsed Laser Deposition ◽  
Critical Current ◽  
Current Density ◽  
Deposition Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Superconducting Transition ◽  
Transition Width

We have investigated epitaxial superconducting SmBa2Cu3O7 (Sm123) films grown by pulsed-laser deposition on single-crystal SrTiO3 substrates. The deposition temperature plays an important role in determining the superconducting properties of Sm123 films. The superconducting transition temperature increases with the deposition temperature whereas the transition width decreases at deposition temperatures in the range of 700–875 °C. A Sm123 film deposited at 850 °C exhibits a transition temperature above 93 K with a transition width less than 0.5 K. Even though Sm123 films exhibit a higher transition temperature than Yba2Cu3O7 (Y123), the Sm123 shows lower critical current density at liquid-nitrogen temperature. The nominal critical current density of Sm123 film is less than 1 MA/cm2 at 75.4 K. Nevertheless, the Sm123 films have less anisotropy and stronger pinning characteristics compared to Y123. They are also much smoother with fewer particulates, as revealed by scanning electron microscopy.

Crystal Growth of High Temperature Superconductors

MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 56-61 ◽  
Author(s):  
H.J. Scheel ◽  
F. Licci
Keyword(s):  
High Temperature ◽  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Large Scale ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Theoretical Understanding

The discovery of high temperature superconductivity (HTSC) in oxide compounds has confronted materials scientists with many challenging problems. These include the preparation of ceramic samples with critical current density of about 106 A/cm2 at 77 K and sufficient mechanical strength for large-scale electrotechnical and magnetic applications and the preparation of epitaxial thin films of high structural perfection for electronic devices.The main interest in the growth of single crystals is for the study of physical phenomena, which will help achieve a theoretical understanding of HTSC. Theorists still do not agree on the fundamental mechanisms of HTSC, and there is a need for good data on relatively defect-free materials in order to test the many models. In addition, the study of the role of defects like twins, grain boundaries, and dislocations in single crystals is important for understanding such parameters as the critical current density. The study of HTSC with single crystals is also expected to be helpful for finding optimum materials for the various applications and hopefully achieving higher values of the superconducting transition temperature Tc than the current maximum of about 125 K. It seems unlikely at present that single crystals will be used in commercial devices, but this possibility cannot be ruled out as crystal size and quality improve.

scholarly journals Temperature Dependence of the Zero-Field In-Plane Critical Current Density of YBa2Cu3O7-d High-Tc Superconductors

2012 ◽  
Vol 4 (2) ◽  
pp. 287 ◽  
Author(s):  
M. R. H. Sarkar ◽  
S. H. Naqib
Keyword(s):  
Critical Current Density ◽  
Temperature Dependence ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Hole Concentration ◽  
Oxygen Deficiency ◽  
Magnetic Hysteresis ◽  
Zero Field ◽  
Different Temperatures

The nature of the temperature dependence of the zero-field critical current density, Jc0(T), in the CuO2 planes has been investigated for c-axis oriented YBa2Cu3O7-d (Y123) thin films over a range of hole content, p. The hole concentration was varied by changing the oxygen deficiency, d, in the CuO1-d chains by annealing the films under different oxygen partial pressures and temperatures. The Jc0(T) values were extracted from the magnetic hysteresis (M-H) loops obtained at different temperatures. From the analysis of the Jc0(T) data for different sample compositions, we have extracted valuable information regarding the nature of the underlying magnetic flux pinning mechanisms in Y123 superconductors. We have found that the oxygen defects play only a secondary role in pinning of the vortices, the superfluid density, on the other hand plays a significant role. The exponent, n, governing the Jc0(T) behavior for a given sample composition showed a systematic behavior as hole contents are changed. Keywords: Y123 superconductors; Critical current density; Flux pinning.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i2.9653 J. Sci. Res. 4 (2), 287-296 (2012)

Microwave Synthesis of Nano SiC Doping Mg(B1-2x(SiC)x)2 Superconductor and Superconductivity

2012 ◽  
Vol 512-515 ◽  
pp. 11-16
Author(s):  
Yuan Dong Peng ◽  
Qing Lin Xia ◽  
Qian Ming Huang ◽  
Li Ya Li ◽  
Hong Zhong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Direct Synthesis ◽  
Xrd Analysis ◽  
Magnetization Measurement ◽  
Superconducting Transition ◽  
Short Time

Superconductor samples Mg(B1-2x(SiC)x)2 (x=0, 5%, 10%) are synthesized from nano SiC, Mg and amorphous boron powders by microwave direct synthesis in a short time. Powder X-ray diffraction (XRD) analysis indicates that the phases of the synthesis sample are MgB2 (major phase) and a small amount of MgO and Mg2Si. The main peaks of MgB2, (100), (101), (002) and (110) are shift to the higher diffraction angle position and the width of half height of the diffraction plane is broaden for the SiC doping Mg(B1-2x(SiC)x)2, which show that the B positions of MgB2 are partly substituted and the grains of MgB2 are fine. Scanning electron microscope (SEM) observation shows that the MgB2 grain size is very small and the sample is tightness (compact). The onset superconducting transition temperature of the Mg(B1-2x(SiC)x)2 (x=0, 5%, 10%) samples measured by magnetization measurement are about 37.6 K, 37.0 K, 36.8 K respectively. The critical current density Jc are calculated according to the Bean model from the magnetization hysteresis loop of the slab Mg(B1-2x(SiC)x)2 (x=0, 5%, 10%) samples. The critical current density Jc of nano SiC doping Mg(B1-2x(SiC)x)2 samples are greatly enhanced. In higher external magnetic field, the Jc of 10% SiC doped sample is the highest; in lower external magnetic field, the Jc of 5% SiC doped sample is the highest; while in the whole external magnetic field, the Jc of undoped sample is the lowest.

AC SUSCEPTIBILITY OF YBCO SUPERCONDUCTING THIN FILMS

2006 ◽  
Vol 20 (15) ◽  
pp. 923-929
Author(s):  
C. SBÂRCIOG ◽  
T. R. REDAC ◽  
I. GR. DEAC
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ac Susceptibility ◽  
Superconducting Thin Films ◽  
Superconducting Transition ◽  
Susceptibility Data ◽  
Complex Susceptibility ◽  
Intergranular Critical Current Density

Ca -doped (x = 0.00, 0.07 and 0.20) epitaxial Y 1-x Ca x Ba 2 Cu 3 O 7-δ thin films were prepared on SrTiO 3 (100) by PLD technique. The superconducting transition temperature is found to decrease with increasing Ca content. The AC-susceptibility data were used to determine the intergranular critical current density, when varying the field amplitude H AC . The temperature dependence of critical current density was determined from the imaginary part of the complex susceptibility, χ′′(T), using Xing's relation. The results were analyzed in terms of superconductor-insulator-superconductor (SIS) and superconductor-normal-superconductor (SNS) type models.

High Critical Current Density of a MgB2 Bulk Superconductor High-pressure Synthesized Directly from the Elements

2002 ◽  
Vol 17 (3) ◽  
pp. 525-527 ◽  
Author(s):  
C-Q. Jin ◽  
S-C. Li ◽  
J-L. Zhu ◽  
F-Y. Li ◽  
Z-X. Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Transition ◽  
High Critical Current Density ◽  
Bulk Superconductor ◽  
High Pressure Sintering ◽  
Current Densities ◽  
Pressure Synthesis

We report the property studies of a MgB2 superconductor with high critical current density. The MgB2 superconductor was readily fabricated through a direct high-pressure synthesis of the respective elements. The obtained high-density MgB2 undergoes a sharp superconducting transition at 39 K. The bulk critical current density (Jc) of the sample was calculated on the basis of Bean's critical state model, and rather high critical current densities over a wide temperature range were obtained in comparison with the ambient prepared samples. The results highlight that high-pressure sintering would be a promising way to produce and search for this kind of intermetallic boride and the related superconductors.

INDUCTIVE CHARACTERIZATION OF SUPERCONDUCTING NANO-ENGINEERED ARTIFICIAL CUPRATES

2003 ◽  
Vol 17 (04n06) ◽  
pp. 393-399
Author(s):  
P. G. MEDAGLIA ◽  
P. ORGIANI ◽  
C. ARUTA ◽  
G. BALESTRINO ◽  
A. TEBANO
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Superconducting Transition ◽  
Engineered Structures

Ultrathin artificial high temperature superconducting structures were grown by pulsed laser deposition stacking in sequence epitaxial layers of ( Ba 0.9 Nd 0.1) CuO 2+x and CaCuO2. Critical temperature Tc and critical current density Jc for such nano-engineered structures consisting of a single (CaCuO2) block sandwiched between two ( Ba 0.9 Nd 0.1) CuO 2+x charge reservoir blocks were measured inductively. The onset of superconducting transition is higher than 50 K. The purely intralayer critical current density was measured at 4.2 K and resulted to be larger than 108 A/cm2.

Radiation Damage in YBa2Cu3O7 by Fast Neutrons

1987 ◽  
Vol 99 ◽  
Author(s):  
J. O. Willis ◽  
J. R. Cost ◽  
R. D. Brown ◽  
J. D. Thompson ◽  
D. E. Peterson
Keyword(s):  
Transition Temperature ◽  
Critical Current Density ◽  
Fast Neutron ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Transition Temperature ◽  
Fast Neutrons ◽  
Zero Field ◽  
Superconducting Transition ◽  
Fast Neutron Irradiation

ABSTRACTThe superconducting transition temperature of sintered YBa2Cu3O7 decreases at a rate of 2.7 K/1018 n/cm2 (E > 0.1 MeV) for fast neutron irradiation. The critical current density Jc increases a factor of three at zero field and more than three at nonzero fields for fluences up to 2×1018 n/cm2. At both 7 and 75 K, Jc is decreasing with fluence near 3×1018 n/cm2.

Stoichiometric effects in epitaxial Ba2−xY1−yCu3−zO7−δ thin films on LaAlO3(100)

1990 ◽  
Vol 5 (12) ◽  
pp. 2797-2801 ◽  
Author(s):  
Douglas J. Carlson ◽  
Michael P. Siegal ◽  
Julia M. Phillips ◽  
T. H. Tiefel ◽  
J. H. Marshall
Keyword(s):  
Thin Films ◽  
Critical Temperature ◽  
Surface Morphology ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Transition ◽  
Transition Width ◽  
Composition Control ◽  
Order Of Magnitude

Stoichiometric deviations of up to ±5% in Ba2YCu3O7−δ, thin films grown by coevaporation on LaAlO3(100) substrates are found to cause (1) a decrease of the critical current density (Jc) of up to an order of magnitude, (2) a depression of the critical temperature (Tc) and a broadening of the superconducting transition width (ΔT), (3) a deterioration of the surface morphology, and (4) a decrease in the crystallinity of the films. The data indicate that composition deviations of greater than ±1% result in degradation of film quality. These findings have significant implications for the degree of composition control required during deposition to produce films with optimized properties.

scholarly journals Influence of He ion etching on superconducting transition temperature and critical current density of Bi1.6Pb0.4Sr2Ca2Cu3Ox.

1994 ◽  
Vol 6 (1) ◽  
pp. 11-13
Author(s):  
Kageyoshi Sakamoto ◽  
Hirokazu Ishii ◽  
Tetsuji Tanihira ◽  
Noriyuki Inoue ◽  
Toshio Shima ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Ion Etching
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