AgO Doped YBa2Cu4O8 Superconductor Under High Oxygen Partial Pressure

1991 ◽  
Vol 251 ◽  
Author(s):  
Yuichi Sawai ◽  
K. Ishizaki ◽  
M. Takata ◽  
A. Kuzjukevics
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Critical Current ◽  
Current Density ◽  
High Oxygen ◽  
Silver Doping ◽  
High Oxygen Partial Pressure ◽  
Pressing Method

ABSTRACTGeneraly silver doping into YBa2Cu3O7 superconductor improves the critical temperature and critical current density. In this work the silver peroxide was doped into YBa2Cu4O8 superconductor and sintered by the Oxygen Hot Isostatically Pressing method. The critical temperature of the 124 phase increased by silver peroxide doping.

Textured YBaCuO Films Enhanced by Cold Rolling and Melt Growth Process in Low Oxygen Partial Pressure

2005 ◽  
Vol 105 ◽  
pp. 453-458 ◽  
Author(s):  
J. Wang ◽  
N. Maloufi ◽  
Xiang Xin Xue ◽  
Z.G. Fan ◽  
Claude Esling
Keyword(s):  
Critical Current Density ◽  
Cold Rolling ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Critical Current ◽  
Current Density ◽  
Control Sample ◽  
Secondary Phase ◽  
Low Oxygen ◽  
Texture Orientation

High critical current density Jc under high magnetic field is required in numerous applications for high temperature superconductor YBa2Cu3O7-δ (Y123). Significant efforts have been made to control sample preparation in view of optimized textures and microstructures. In YBa2Cu3O7-δ superconductor, Jc is limited by grain misalignment and by other defaults like secondary phase (Y211), microcracks... So YBaCuO films were prepared by electrophoretic deposition directly on polycrystalline Ag substrate. Melt textured growth (MTG) in low oxygen partial pressure and cold rolling were performed to YBaCuO samples respectively to improve texture growth of the films and to study deformation effect on the texture. The film obtained by melted growth after rolling has better texture orientation than the film without rolling, and presents higher critical current density.

scholarly journals Distinct doping dependence of critical temperature and critical current density in Ba1−xKxFe2As2 superconductor

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Dongjoon Song ◽  
Shigeyuki Ishida ◽  
Akira Iyo ◽  
Masamichi Nakajima ◽  
Jun-ichi Shimoyama ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Doping Dependence

Porosity Effect on Superconducting Properties of YBa2Cu3Oδ and YCaBa4Cu6Oδ

2015 ◽  
Vol 1107 ◽  
pp. 601-605
Author(s):  
S.A. Senawi ◽  
H. Azhan ◽  
W.N.F.W. Zainal ◽  
W.A.W. Razali ◽  
A. Nazree ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Porous Structure ◽  
Critical Current ◽  
Current Density ◽  
Resistivity Measurement ◽  
Effective Cross Section ◽  
Ceramic Materials ◽  
Solid State Reaction Method ◽  
Superconducting Properties

This paper reports on the properties of YBa2Cu3Od (Y123) and YCaBa4Cu6Oy (Y146) with non-porous and porous structures. The relationship between calcium doping and critical temperature (Tc) was studied to determine the optimal superconducting properties. A series of heating and grinding via solid state reaction method was used to fabricate the ceramic materials. The electrical properties were investigated via critical temperature, TC and critical current density, JC using the resistivity measurement system (RMS). Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) were used to analyze the material morphology and structure, respectively. The orthorhombicity increased due to less porosity of the samples. The calcium presence partially replaced larger Ba(II) site and degraded orthorhombicity. The highest critical current density (JC) was porous YCaBa2Cu3Oy which was 2.32 A/cm2 compared to 0.75 A/cm2 for porous YCaBa4Cu6Oy at 60 K. The critical temperature for porous structure was less than non porous structure for Ca doped Y146 system which was 69.9 K and 67.9 K. SEM micrograph unveiled that the Jc was induced significantly by continuity of grain formation via grain size. Pores homogenized the grains surface quality and connectivity due to strain release thus increasing effective cross section of the sample for current density (Jc) over the vast areas.

Irradiation Defect Structures In YBa2Cu3O7-xand their Correlation with Superconducting Properties

1990 ◽  
Vol 209 ◽  
Author(s):  
Marquis A. Kirk
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Neutron Irradiation ◽  
Current Density ◽  
Amorphous Material ◽  
Amorphous Structure ◽  
Fast Neutrons ◽  
High Fluences ◽  
Defect Microstructures

ABSTRACTWe review our work on irradiation effects in single crystal YBa2Cu3O7-x. Transmission electron microscopy has been employed to study the defect microstructures produced by irradiations with fast neutrons, MeV ions (Kr, Ne and p), and electrons. The atomic structure within defect cascades was investigated using 50 keV Kr and Xe ion irradiations to low doses. Evidence is shown for an amorphous structure with some incoherent recrystallization within individual cascades. Correlation with enhancements in critical current density produced by neutron irradiations suggest that this cascade structure effectively pins magnetic flux lines.At sufficiently high fluences of fast neutrons or MeV Kr and Ne ions, a cellular microstructure is found. This structure consists of cells or microcrystallites of good crystalline and superconducting material (in the case of neutron irradiation), with cell walls of amorphous material. Full amorphization proceeds with the growth of cell wall volume. The formation of this microstructure coincides with a decrease in critical transport current, but is not observed by magnetization measurements.Increases in critical current density under proton irradiation, comparable to those produced by neutron irradiation, have been reported. The defect structure produced by proton irradiations is examined here and found to differ from that of neutron irradiations. The structure is suggested to be consistent with the clustering of mobile defects (at 300 K) produced by the lower energy recoils which dominate in proton irradiations. In both the proton and fast neutron irradiations, to fluences producing the maximum enhancements in critical current densities, the degradations in critical temperature are not severe, <10 K.Our most recent measurements of changes in critical temperature and current density, and defect microstructure following electron irradiations will be described

Sign in / Sign up

Export Citation Format

Share Document