STUDIES OF F ON SUPERCONDUCTIVITY IN HIGH-Tc (Bi,Pb)SrCaCu(O,F) SUPERCONDUCTORS

In this article, the experimental results of the superconductivity in high-Tc (Bi,Pb) 2 Sr 2 Ca 2 Cu 3( O y, F x), x = 0–0.84, is described. Its critical current density Jc is about ten times larger than that of undoped F sample undergoing the same technology. The causes for the increase in Jc are studied by several experimental methods. The difference in quantity between Meissner effect and shield effect indicates that the effect on superconductivity is from the weak-link regions of the superconductor grains. SEM shows that F atoms doped in BPSCCO superconductor can make its grains grow larger, arrange regularly, and increase in touch area. These changes strengthen the netty link between grains. The magnitude of residual magnetization of F-doped sample is eight times as large as that of the undoped one. The flux pinning potential U0 is calculated from the Bean model. The U0 in F-doped sample (when H = 64 Oe, x = 0.64) is eight times as large as that in the undoped one.

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MAGNETO-OPTIC IMAGING OF PROTON-IRRADIATED HIGH Tc SUPERCONDUCTING THIN FILMS: A REVISIT OF Jc(T) FUNCTIONAL AND FLUX PINNING ENHANCEMENT

International Journal of Modern Physics B ◽

10.1142/s0217979201007762 ◽

2001 ◽

Vol 15 (24n25) ◽

pp. 3357-3358

Author(s):

Chong Wang ◽

Hye-Won Seo ◽

Chun-Jung Su ◽

Yuh-Huah Wang ◽

Q. Y. Chen ◽

...

Keyword(s):

Thin Films ◽

Magnetic Fields ◽

External Field ◽

Critical Current Density ◽

Current Density ◽

Flux Pinning ◽

Ybco Film ◽

Superconducting Thin Films ◽

High Tc ◽

Quantitative Measurements

We have performed systematic quantitative measurements of the critical current density Jc(B, T) for YBCO thin films proton-irradiated to various dosages using the MOI technique. Results for external magnetic fields up to 400Oe and temperature ranging from 5 to 80K are presented for a 600nm thick YBCO film irradiated by proton up to a dosage of 1016 cm -2 at 500 keV. While no significant differences were observed for T>50K, the Jc values consistently increased with the increasing external field for T<50K.

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MAGNETIC PROPERTIES OF THE HIGH Tc SUPERCONDUCTORS BiSrCaCuO AND TlBaCaCuO

International Journal of Modern Physics B ◽

10.1142/s0217979289000051 ◽

1989 ◽

Vol 03 (01) ◽

pp. 77-85 ◽

Cited By ~ 3

Author(s):

Y. D. DAI ◽

C. LIN ◽

W. B. ZHANG ◽

S. Q. FENG ◽

X. ZHU ◽

...

Keyword(s):

Magnetic Properties ◽

Flux Pinning ◽

Magnetic Hysteresis ◽

Hysteresis Loops ◽

High Tc Superconductors ◽

Magnetic Current ◽

High Tc ◽

Bean Model ◽

Current Densities ◽

Magnetic Hysteresis Loops

Magnetic properties of the high T c superconductors BiSrCaCuO and TlBaCaCuO were investigated systematically. Magnetic current densities were calculated from magnetic hysteresis loops of bulk and powdered samples by Bean model. The results showed that flux pinning in these materials is much weaker than that in YBaCuO.

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Magnetic field and temperature dependence of the transport critical current density and flux pinning in anisotropic (Bi,Pb)2Sr2Ca2Cu3Ox high Tc superconductor

Cryogenics ◽

10.1016/0011-2275(92)90017-5 ◽

1992 ◽

Vol 32 (11) ◽

pp. 1005-1009 ◽

Cited By ~ 5

Author(s):

P. Kottman ◽

H. Jones ◽

V. Plecháček ◽

M. Polák

Keyword(s):

Magnetic Field ◽

Critical Current Density ◽

Temperature Dependence ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

Transport Critical Current Density ◽

High Tc ◽

High Tc Superconductor

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The critical current density, irreversibility line, and flux pinning properties of Ba2CaCu2O4(O,F)2 high-Tc superconductor

Journal of Applied Physics ◽

10.1063/1.3369446 ◽

2010 ◽

Vol 107 (9) ◽

pp. 093905 ◽

Cited By ~ 4

Author(s):

P. M. Shirage ◽

Y. Tanaka ◽

A. Iyo

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

Irreversibility Line ◽

High Tc ◽

High Tc Superconductor ◽

Pinning Properties

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Critical Current Density and Flux Pinning Properties in Superconducting MgB2 with and without SiC Doping

Materials Science Forum ◽

10.4028/www.scientific.net/msf.750.293 ◽

2013 ◽

Vol 750 ◽

pp. 293-297

Author(s):

Wen Xu Sun ◽

Bao Rong Ni ◽

Akiyoshi Matsumoto ◽

Hiroaki Kumakura

Keyword(s):

Magnetic Field ◽

Critical Current Density ◽

Critical Current ◽

High Magnetic Field ◽

Current Density ◽

Flux Pinning ◽

Critical Magnetic Field ◽

Pinning Mechanism ◽

Pinning Potential ◽

Force Displacement

It is well known that SiC doping in superconducting MgB2 improves the upper critical magnetic field (Bc2) and the critical current density (Jc) under high magnetic field. However, the relationship between SiC doping and the flux pinning mechanism has not been clarified. In this study, several MgB2 samples with and without SiC doping were prepared by the conventional in situ powder-in-tube method. The critical current densities and the force-displacement characteristics of fluxoids in samples were investigated by an ac inductive measurement (Campbell’s method). The Labusch parameter (αL) and the interaction distance (di) were estimated from the obtained force-displacement profile. It was found that SiC doping enhances the values of αL, but does not change the characteristics of the magnetic field dependence of αL apparently. Namely, αL vs. B3/2 characteristics in the pure samples and SiC doped samples are almost the same. Such a result of αL properties implies that the pinning mechanism in the SiC doped samples could be consistent with the conventional pinning theory. On the other hand, di, which is considered to be proportional to the size of pinning potential, decreases rapidly with increasing magnetic field, especially in the pure samples. For high magnetic field region, the variations of di were deduced to be caused by flux creep. The depth of pinning potential, U0, was estimated by using the values of αL and di. The values of U0 give evidence of that SiC doping can prevent the flux bundles moving to another pinning center under high magnetic field.

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