Enhancement in Critical Current Density of Bi2Sr2CaCu2O8+x Single Crystal by Neutron Irradiation Followed by Thermal Annealing — Effect of Neutron Fluence —

1999 ◽  
pp. 541-544 ◽  
Author(s):  
K. Ogikubo ◽  
T. Kobayashi ◽  
T. Terai ◽  
S. Tanaka ◽  
K. Kishio
1989 ◽  
Vol 169 ◽  
Author(s):  
R. B. van Dover ◽  
E. M. Gyorgy ◽  
L. F. Schneemeyer ◽  
A. E. White ◽  
S. Glarum ◽  
...  

AbstractThe critical current density, Jc, of single crystals of Ba2YCu3O7 is comparable to that of melt-textured-growth materials as well as to the intragrain Jc of bulk polycrystalline Ba2YCu3O7. Typical values at 77 K and 9 kOe are near 5x 103 A/cm2, and are presumably limited by weak pinning. We have obtained a significant enhancement of this pinning-limited Jc by three techniques: 1) a short reannealing procedure, 2) fast neutron irradiation, and 3) proton irradiation. Interestingly, the combination of the first technique followed by either irradiation is not as effective as the iradiation alone. That is, the best candidates for irradiation are not necessarily those with the highest initial Jc.


2021 ◽  
Vol 21 (9) ◽  
pp. 4941-4943
Author(s):  
Sang Heon Lee

In the present study, a YBa2Cu3O7−y bulk superconductor added with 5~10 wt% Ag was fabricated employing Sm123 as a seed to produce a superconductive single crystal. Metallic silver was added to the single crystal of YBa2Cu3O7−y to remove defects such as cracks and pores. Electromagnetic properties of the bulk superconductor at 77 K were analyzed based on relationships of magnetic levitation, trapped magnetic force, and critical current density. The critical current density of the superconductor at 77 K and 0 T was 3.53 × 104 A/cm2. Discontinuous points in the distribution of magnetic field lines were not observed, implying that these two specimens grew well as a single crystal without specific weak links. For the growth of a superconductive nano crystal employing slow cooling at temperature of formation of 123 phase, superconductive nano crystals were aligned in a-b direction, the direction of peak current flow. The peak value of the trapped magnetic force of the YBa2Cu3O7−y superconductor specimen was 3.23 kG. Using the FC method, peak forces of attraction and repulsion were 21.696 N and 70.168 N, respectively.


2015 ◽  
Vol 92 (14) ◽  
Author(s):  
Yue Sun ◽  
Sunseng Pyon ◽  
Tsuyoshi Tamegai ◽  
Ryo Kobayashi ◽  
Tatsuya Watashige ◽  
...  

2003 ◽  
Vol 82 (25) ◽  
pp. 4519-4521 ◽  
Author(s):  
S. R. Foltyn ◽  
P. N. Arendt ◽  
Q. X. Jia ◽  
H. Wang ◽  
J. L. MacManus-Driscoll ◽  
...  

2010 ◽  
Vol 150 (27-28) ◽  
pp. 1178-1181 ◽  
Author(s):  
S.V. Chong ◽  
S. Hashimoto ◽  
K. Kadowaki

1990 ◽  
Vol 209 ◽  
Author(s):  
Marquis A. Kirk

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


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