Improvement of Critical Current Density in Bi-2223 Superconductor by Ag-Doping

High-Tc superconducting polycrystalline Bi-2223 undoped sample (A0) and 5wt.% Ag-doped sample (A5) have been prepared by solid-state reaction method at 8550C with sintering time of 8 days. X-ray powder diffraction (XRD) results shown that the major phase of these samples is Bi-2223. The volume ratio of Bi-2223 phase observed to be increased from 78% for undoped sample (A0) to 95% for 5wt.% Ag-doped sample (A5). The enhancement of the onset of high-Tc superconductivity (Tc,onset = 112.5 K) in silver doping sample was observed by DC-resistivity measurements. From the AC-susceptibility measurements combined with Bean critical state model, the temperature dependent parabolic law of inter-granular or matrix critical current density (Jcm) was fitted. Some Jcm values were estimated from these parabolic laws. The results showed that 5wt% Ag-doping can make the Bi-2223 sample with nearly double critical current density.

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INTERGRANULAR PROPERTIES OF (Y1-x-yZrxCay)Ba2Cu3O7-δ COMPOUNDS

International Journal of Modern Physics B ◽

10.1142/s0217979299001624 ◽

1999 ◽

Vol 13 (13) ◽

pp. 1645-1654 ◽

Cited By ~ 9

Author(s):

I. GR. DEAC ◽

E. BURZO ◽

A. V. POP ◽

V. POP ◽

R. TETEAN ◽

...

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Ac Susceptibility ◽

Temperature Dependent ◽

Susceptibility Data ◽

Dc Magnetic Field ◽

Complex Susceptibility ◽

Granular Superconductors ◽

Intergranular Critical Current Density

The intergranular properties of ( Y 1-x-y Zr x Ca y) Ba 2 Cu 3 O 7-δ ceramics were studies by using temperature-dependent ac susceptibility measurements at zero dc magnetic field. The intergranular critical current density was determined from ac susceptibility data by varying the field amplitude H ac . From the imaginary part of the complex susceptibility, χ″(T), we have determined the temperature dependence of the critical current density by using the Bean's model. The ac field dependencies of the intergrain χ″-peak temperatures T p are linear and agree with Müller critical state model. The results were analyzed in terms of superconductor-insulator-superconductor (SIS)-and superconductor-normal-superconductor (SNS)-type models for granular superconductors.

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Effect of Nano-Sized Nickel Ferrite Addition on Superconducting Properties of (Tl0.85Cr0.15)Sr2CaCu2O7-δ Superconductors

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.290.227 ◽

2019 ◽

Vol 290 ◽

pp. 227-232

Author(s):

Wei Kong ◽

Ing Kong ◽

Nur Akasyah Jaafar ◽

M. Aizat Kamarudin ◽

Nurul Raihan Suib ◽

...

Keyword(s):

Transition Temperature ◽

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Nickel Ferrite ◽

Ac Susceptibility ◽

High Temperature Superconductors ◽

Diffraction Method ◽

Solid State Reaction Method ◽

Transport Critical Current Density

The effect of nanosized nickel ferrite (NiFe2O4) addition on (Tl0.85Cr0.15)Sr2CaCu2O7-δ superconductors has been investigated. (Tl0.85Cr0.15)Sr2CaCu2O7-δ high temperature superconductors was prepared via solid-state reaction method using high purity oxide powders. Nanosized NiFe2O4 was added to the compound at composition x = 0 - 0.003 wt.%. Samples were studied using scanning electron microscopy (SEM), X-ray diffraction method (XRD), electrical resistance versus temperature, transport critical current density Jc and AC susceptibility measurements. SEM micrographs showed close-packed microstructure with low porosity. XRD patterns showed a dominant phase of Tl-1212 with a minor phase of Tl-1201 for all samples. All of the samples displayed metallic normal state behavior before the onset transition temperature (Tc-onset) which was between 102 and 104 K. The transition temperature (Tcχ’) from AC susceptibility measurement also showed the similar results between 101 and 103 K. Tc-zero was slightly suppressed with the addition of nanosized NiFe2O4. The peak temperature Tp from the imaginary part of the susceptibility χ” was found between 77 - 91 K for all samples. The highest transport critical current density (Jc) at 77 K was shown by sample x = 0.001 wt.% at 2213 mAcm-2. Nanosized NiFe2O4 has significantly enhanced the Jc of (Tl0.85Cr0.15)Sr2CaCu2O7-δ superconductor.

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ANOMALOUS INCREASE OF THE TRANSPORT AND INDUCTIVE CRITICAL CURRENT DENSITY DUE TO LOW DC-FIELD COOLING IN SINTERED RBa2Cu3O7−x HIGH Tc SUPERCONDUCTORS

Modern Physics Letters B ◽

10.1142/s0217984991002070 ◽

1991 ◽

Vol 05 (26) ◽

pp. 1727-1733

Author(s):

T. PUIG ◽

M. PONT ◽

J.S. MUÑOZ

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Ac Susceptibility ◽

Transport Critical Current Density ◽

Zero Field ◽

High Tc ◽

Current Densities ◽

Magnetic Flux Pinning ◽

Intergranular Critical Current Density

The transport critical current density of bulk sintered samples of RBa2Cu3O7−x with R=Y, Gd, Ho, and Er has been determined at 77 K from I–V curves at different applied dc-magnetic fields (0≤H≤20 Oe), also the ac-susceptibility as a function of ac-field amplitude has been measured with a superimposed dc-magnetic field from 0 to 30 Oe at 77 K. The transport and magnetic (inductive) critical current densities, are clearly larger in field cooled samples than in zero field cooled samples. Likewise, the degree of shielding as determined from the ac-susceptibility measurements is larger for field cooled samples than for zero field cooled. This anomalous behaviour can be explained in terms of the magnetic flux pinning present in the grains when the sample is field cooled, which leads to a decrease in the magnetic induction of the intergrain region and therefore to a higher intergranular critical current density compared to a zero field cooled sample.

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