scholarly journals A quantitative understanding of the enhanced irreversibility line and critical current density due to linear defects in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals with the vortex dimensionality-crossover model

1992 ◽  
Author(s):  
D.H. Kim ◽  
K.E. Gray ◽  
J.D. Hettinger
2010 ◽  
Vol 78 (3) ◽  
pp. 359-365 ◽  
Author(s):  
M. Ciszek ◽  
K. Rogacki ◽  
K. Oganisian ◽  
N. D. Zhigadlo ◽  
J. Karpinski

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.


MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 56-61 ◽  
Author(s):  
H.J. Scheel ◽  
F. Licci

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.


1991 ◽  
Vol 235 ◽  
Author(s):  
M. E. Reeves ◽  
B. D. Weaver ◽  
G. P. Summers ◽  
R. J. Soulen ◽  
W. L. Olson ◽  
...  

ABSTRACTMeasurements are presented which show the effect of proton irradiation on the irreversibility line and critical current in Tl2 CaBa2Cu2O8 thin films. These data show that the irreversibility line is dependent on the defect structure and that the pinning energy is increased by proton irradiation. This leads to an increase in the critical current density at 60 K for the lowest radiation dose. Further irradiation reduces the critical current, even while the irreversibility line is enhanced.


1995 ◽  
Vol 254 (3-4) ◽  
pp. 213-221 ◽  
Author(s):  
T. Kobayashi ◽  
T. Kimura ◽  
J. Shimoyama ◽  
K. Kishio ◽  
K. Kitazawa ◽  
...  

2020 ◽  
Vol 8 (31) ◽  
pp. 15782-15788 ◽  
Author(s):  
Florian Flatscher ◽  
Martin Philipp ◽  
Steffen Ganschow ◽  
H. Martin R. Wilkening ◽  
Daniel Rettenwander

The critical current density in symmetrical Li metal cells using Li7La3Zr2O12 single crystals is determined. The upper limit at room temperature without applying any external forces is below 300 μA cm−2.


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