scholarly journals Large and significantly anisotropic critical current density induced by planar defects in CaKFe4As4 single crystals

2019 ◽  
Vol 99 (10) ◽  
Author(s):  
Sunseng Pyon ◽  
Ayumu Takahashi ◽  
Ivan Veshchunov ◽  
Tsuyoshi Tamegai ◽  
Shigeyuki Ishida ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Planar Defects

scholarly journals Influence of the carbon substitution on the critical current density and AC losses in MgB2 single crystals

2010 ◽  
Vol 78 (3) ◽  
pp. 359-365 ◽  
Author(s):  
M. Ciszek ◽  
K. Rogacki ◽  
K. Oganisian ◽  
N. D. Zhigadlo ◽  
J. Karpinski
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Ac Losses ◽  
Carbon Substitution

Anisotropic critical current density and flux pinning mechanism of Fe1+yTe0.6Se0.4 single crystals

2021 ◽  
Author(s):  
Yongqiang Pan ◽  
Nan Zhou ◽  
Bencheng Lin ◽  
Jinhua Wang ◽  
Zengwei Zhu ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Pinning Force ◽  
Magnetization Relaxation ◽  
Pinning Mechanism

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.

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.

Exponential field dependence of critical current density of underdoped (La1−xSrx)2CuO4 single crystals

1995 ◽  
Vol 254 (3-4) ◽  
pp. 213-221 ◽  
Author(s):  
T. Kobayashi ◽  
T. Kimura ◽  
J. Shimoyama ◽  
K. Kishio ◽  
K. Kitazawa ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Field Dependence ◽  
Current Density

Studies of Critical Current Density Enhancement in (Cax Y1−x)Ba2Cu4O8 (1:2:4)

1991 ◽  
Vol 235 ◽  
Author(s):  
P. K. Narwankar ◽  
M. R. Chandrachood ◽  
M. Fendorf ◽  
D. E. Morris ◽  
A. P. B. Sinha ◽  
...  
Keyword(s):  
High Resolution ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Defect Density ◽  
High Density ◽  
Planar Defects ◽  
High Defect Density ◽  
Density Enhancement ◽  
High Resolution Tem

ABSTRACTSamples with the stoichiometry (CaxY1−x)Ba2Cu4O8, x = 0, 0.1 were synthesized at P(O2) = 25 and 200 bar. High Resolution TEM images for the samples synthesized at 25 bar show a high density of planar defects as compared to almost defect free microstructure of Ca0.1Y0.9Ba2Cu4O8 synthesized at 200 bar. The intragrain critical current density of the high defect density samples is however about 100 times lower that that of Ca0.1Y0.9Ba2Cu4O8 synthesized at P(O2) = 200 bar.

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