The effect of molding pressure on the structural and electrical properties of Y1Ba2Cu3O7−δ superconductors

1998 ◽  
Vol 13 (8) ◽  
pp. 2067-2070
Author(s):  
C. O. Kim ◽  
J. S. Park ◽  
T. W. Kim
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Electrical Properties ◽  
Critical Current Density ◽  
Current Density ◽  
Molding Pressure ◽  
Superconducting Transition ◽  
Remarkable Effect ◽  
Structural And Electrical Properties ◽  
Oxygen Mole Fraction

Measurements of structural and electrical properties as a function of the molding pressure in Y1Ba2Cu3O7−δ superconductors have been performed to investigate the texturing behavior. The magnitudes of the molding pressure were 0.5 × 103 N/cm2, 1 × 103 N/cm2, 2 × 103 N/cm2, and 4 × 103 N/cm2. As the molding pressure increases, the anisotropy of the crystal structure decreases and the crystal grows preferentially along the c-axis. As the molding pressure increases, since the size of the grain becomes larger due to the decreased porosity, denser textures are formed. This result indicates that the critical current density is improved, resulting in increased thermal stability at higher molding pressure. While the molding pressure does not affect the oxygen mole fraction below 500 °C, increases in the molding pressure have a remarkable effect on the formation of textures and on the onset temperature for the superconducting transition in Y1Ba2Cu3O7−δ. These results indicate that structural and electrical properties in Y1Ba2Cu3O7−δ superconductors are affected by the molding pressure during growth.

High Pressure Synthesized Magnesium Diboride- and Dodecaboride-Based Superconductors: Structure and Properties

2010 ◽  
Vol 670 ◽  
pp. 21-27 ◽  
Author(s):  
Tatiana Prikhna ◽  
Wolfgang Gawalek ◽  
Yaroslav Savchuk ◽  
Athanasios G. Mamalis ◽  
Vasiliy Tkach ◽  
...  
Keyword(s):  
High Pressure ◽  
Transition Temperature ◽  
Critical Current Density ◽  
Current Density ◽  
Magnesium Diboride ◽  
Synthesis Temperature ◽  
Superconducting Transition ◽  
Structure And Properties ◽  
Synthesized Materials ◽  
Critical Current Density Jc

The critical current density, jc, of high-pressure synthesized MgB2-based balk materials correlates with the amount and distribution of higher borides (MgB12) and Mg-B-O inclusions, which in tern correlates with the synthesis temperature and presence of additions (Ti, Ta, SiC). High-pressure-synthesized materials with near MgB12 composition of matrix exhibited superconducting transition temperature, Tc, of about 37 K, rather high jc (5∙105 and 103 A/cm2 in 0 T and 3.5 T, respectively, at 20 K) and doubled matrix microhardness: 25±1.1 GPa at 4.9 N –load as compared to materials with MgB2).

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.

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.

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.

Influence of Ta2O5, TiO2, and ZrO2 Interfacial Layers on Structural and Electrical Properties of Laser Ablated Ba0.5Sr0.5TiO3 Thin Films

2002 ◽  
Vol 748 ◽  
Author(s):  
Suprem R. Das ◽  
Rasmi R. Das ◽  
P. Bhattacharya ◽  
Ram S. Katiyar
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Buffer Layers ◽  
Bst Thin Films ◽  
Interfacial Layers ◽  
Average Grain Size ◽  
Structural And Electrical Properties

ABSTRACTPulsed laser deposition technique was used to fabricate Ba0.5Sr0.5TiO 3 (BST) thin-films on Pt/TiO 2/SiO2/Si substrates. The influence of thin interfacial layers of Ta2O5, TiO2, and ZrO2, on the structural and electrical properties of BST thin films was investigated. Insertion of interfacial layers does not affect the perovskite phase formation of BST thin films. Buffer layers helped to make uniform distribution of grains and resulted in a relative increase in the average grain size. The dielectric tunability of BST thin films was reduced with the presence of buffer layers. A BST thin film having a dielectric permitivity of 470 reduced to 337, 235 and 233 in the presence of Ta2O5, TiO2, and ZrO2 layers, respectively. The reduction of the relative dielectric permittivity of BST films with the insertion of interfacial layers was explained in terms of a series capacitance effect, due to the low dielectric constant of interfacial layers. The TiO2 layer did not show any appreciable change in the leakage current density. Deposition of thin Ta2O5 and ZrO2 interfacial layer on top of Pt reduced the leakage current density by an order of magnitude.

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.

A Study of Substitution the Element of (La+3) on the Structural and Electrical Properties of the Compound Ferrite (𝐂𝐨𝟎.𝟐𝟓𝑵𝒊𝟎.𝟐𝟓𝐙𝐧𝟎.𝟓𝐋𝐚𝐱𝐅𝐞𝟐−𝐱𝐎𝟒)

2021 ◽  
Vol 19 (3) ◽  
pp. 56-61
Author(s):  
Bilal Ahmed Omar ◽  
Rabab Shakour Ali
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Spontaneous Combustion ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Scanning Electron

The ferritic nanocomposite which prepared has the chemical formula of (Co0.25𝑁𝑖0.25Zn0.5LaxFe2−xO4), for different values of (X= 0, 0. 25, 0. 5, 0. 75), by using the spontaneous combustion-gel method, where calcination had been at temperature of (700˚C) for two hours; then studied the structural properties of the resulting ferrite via X-Ray diffraction (XRD), and Scanning Electron Microscopy (SEM) The results denote that the ferrite has a unique phase with a spinal-shaped crystal structure and a granular size are (23-36) nm, with increase in lattice constant of decrease in porosity, and electrical properties were also take in to consideration, like value of dielectric constant, the loss coefficient also observed via increase the frequency. The alternating electrical conductivity (σa.c) increases with increasing frequency.

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