scholarly journals Improvement of MTG Process for Preparation and its property of YBCO Superconductor

2016 ◽  
Vol 1 (1) ◽  
pp. 39
Author(s):  
Dea-wha Soh

<p>To improve the superconductivity of high temperature YBCO superconductor, it was prepared and examined by MTG (melt-textured growth) process with use of SmBaCuO seed crystal for orientation, additives of Ag and 211 phase for current density and flux pinning, and heat treatment for oxygen absorption. SmBaCuO single crystals were prepared by MTG process with oxygen absorption and analyzed by XRD and Laue technique. It was estimated that optimum value of Y<sub>2</sub>BaCuO<sub>5</sub> (211 phase) contents in the textured YBCO superconductor as flux pinning center was about 20 wt.%. Ag contents have no influence on the critical temperature but have large influence on the critical current density of the textured YBCO. In the YBCO matrix in experiment, 10 wt.% of Y<sub>2</sub>BaCuO<sub>5</sub> was added, the final 211 content of YBCO made by MTG process could reach about 20 wt.% which was the optimum value for the critical current density. The Ag contents in textured YBCO and the effects of Ag on the superconductivity were also examined. A 5x5x2 mm<sup>3</sup> single crystal of SmBaCuO grown by the melted-condensed process was used to be the seed crystal in the preparation of YBCO. It was proved that the orientation of YBCO was the same as the orientation of the SmBaCuO seed. The effect of oxygen absorption of the bulk oriented YBCO was studied and the heat treatment of oxygen absorption would be in flowing oxygen, at 400 for about 24 hours. The critical current density of the textured YBCO prepared by the optimum technical conditions was about 7x10<sup>4</sup> A/cm<sup>2</sup> (77K, 0.01T).</p>

1995 ◽  
Vol 250 (1-2) ◽  
pp. 55-58 ◽  
Author(s):  
R.L. Wang ◽  
H.C. Li ◽  
B. Yin ◽  
J.W. Li ◽  
X.S. Ron ◽  
...  

2006 ◽  
Vol 74 (17) ◽  
Author(s):  
J. Chen ◽  
V. Ferrando ◽  
P. Orgiani ◽  
A. V. Pogrebnyakov ◽  
R. H. T. Wilke ◽  
...  

2011 ◽  
Vol 324 ◽  
pp. 241-244 ◽  
Author(s):  
R. Mawassi ◽  
R. Awad ◽  
Mohamad Roumie ◽  
M. Kork ◽  
I. Hassan

The major limitation of Bi-system superconductor applications is the intergrain weak links and weak flux pinning capability producing low critical current density of the Bibased phases. In order to enhance these characteristics and other superconducting properties, effective flux pinning centers are introduced into high temperature superconductors. In this work, different weight percentages of ZnO nano oxide were introduced at the final stage of the Bi1.8Pb0.4Sr2Ca2Cu3O10-y superconductor preparation process. Phase characterization was completed by X-ray diffraction (XRD). Exact constitution of the samples was determined using particle induced X-ray emission (PIXE). Granular and microstructure were investigated using scanning electron microscopy (SEM). Electrical resistivity as function of the temperature was carried to evaluate the relative performance of samples, and finally, E-J characteristic curves were obtained at 77K. Using 0.4 ZnO weight percentage, the electrical and granular properties were greatly enhanced, indicating more efficient pinning mechanisms. A critical current density of 949 A/cm2 was obtained which represents more than twice the value obtained for the pure sample (Jc= 445 A/cm2).


2018 ◽  
Vol 2 (4) ◽  
pp. 045015 ◽  
Author(s):  
Dinesh Kumar ◽  
Shibnath Samanta ◽  
K Sethupathi ◽  
M S Ramachandra Rao

Author(s):  
Yongqiang Pan ◽  
Nan Zhou ◽  
Bencheng Lin ◽  
Jinhua Wang ◽  
Zengwei Zhu ◽  
...  

Abstract Fe1+yTe0.6Se0.4 has considerable application potential due to its large critical current density (J c) and high upper critical magnetic field (H c2). However, the uncertainty of the anisotropy of J c and the unclear flux-pinning mechanism have limited the application of this material. In this study, the J c in three directions were obtained from magnetic hysteresis loop measurements. A large anisotropy of J c ab /J c c ~ 10 was observed, and the origin of the anisotropy was discussed in details. Flux pinning force densities (F p) were obtained from J c, and a non-scaling behavior was found in the normalized pinning force f p[F p/F p-max] versus the normalized field h[H/H c2]. The peaks of pinning force shift from a high h to a low h with increasing temperature. Based on the vortex dynamics analysis, the peak shift was found to originate from the magnetization relaxation. The J c and F p at critical states free from the magnetic relaxation were regained. According to the Dew-Hughes model, the dominant pinning type in Fe1+yTe0.6Se0.4 clean single crystals was confirmed to be normal point pinning.


1976 ◽  
Author(s):  
A. I. Braginski ◽  
Michael R. Daniel ◽  
G. W. Roland

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