Flux pinning sites in melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu 3Oy superconductors

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Abstract

(Nd0.33Eu0.33Gd0.33)Ba2Cu 3O samples are prepared with extremely fine insulating 211 particles, which are uniformly dispersed in the superconducting matrix. Even though (Nd0.33Eu0.33Gd0.33)2 BaCuO5 powders about 3 μm in diameter were added to the precursor, we have found that Gd2BaCuO5 (Gd-211) inclusions about 0.1 μm in diameter were finely distributed in the (Nd0.33Eu0.33Gd0.33)Ba2C 3Oy matrix. The formation of such fine 211 particles has not been achieved in any other bulk superconductors like YBa2Cu3O7-δ (YBCO) or NdBCO. As a function of the concentration of the 211 particles, the shape of the Jc(Ha) curves at T =77 K can be changed from a very pronounced fishtail behaviour to a plateau-like behaviour, yielding a nearly constant current density up to 2.5 T. The presence of small Gd-211 particles does not inhibit the function of flux pinning provided by composition fluctuations leading to a spatial scatter of the superconducting transition temperature, Tc, as long as the 211 concentration is less than 40 mol%. Therefore, two different pinning centers are simultaneously active in one sample, which is also confirmed by the pinning analysis based on the scaling formalism, where we find peak positions even above 0.5 in the temperature range 60 ≥ T ≥ 93 K. The presence of the composition fluctuations is directly confirmed by means of field-cool cooling and -warming experiments in fields up to 7 T.

Original languageEnglish
Pages (from-to)31-38
Number of pages8
JournalPhysica C: Superconductivity and its Applications
Volume337
Issue number1-4
Publication statusPublished - 2000
Externally publishedYes

Fingerprint

Flux pinning
flux pinning
Superconducting materials
Chemical analysis
Powders
Superconducting transition temperature
Current density
Cooling
matrices
plateaus
Experiments
transition temperature
inclusions
current density
formalism
cooling
scaling
Temperature
heating
curves

Keywords

  • Critical currents
  • Flux pinning
  • Light rare earth 123 superconductors
  • Melt-processing

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

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title = "Flux pinning sites in melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu 3Oy superconductors",
abstract = "(Nd0.33Eu0.33Gd0.33)Ba2Cu 3O samples are prepared with extremely fine insulating 211 particles, which are uniformly dispersed in the superconducting matrix. Even though (Nd0.33Eu0.33Gd0.33)2 BaCuO5 powders about 3 μm in diameter were added to the precursor, we have found that Gd2BaCuO5 (Gd-211) inclusions about 0.1 μm in diameter were finely distributed in the (Nd0.33Eu0.33Gd0.33)Ba2C 3Oy matrix. The formation of such fine 211 particles has not been achieved in any other bulk superconductors like YBa2Cu3O7-δ (YBCO) or NdBCO. As a function of the concentration of the 211 particles, the shape of the Jc(Ha) curves at T =77 K can be changed from a very pronounced fishtail behaviour to a plateau-like behaviour, yielding a nearly constant current density up to 2.5 T. The presence of small Gd-211 particles does not inhibit the function of flux pinning provided by composition fluctuations leading to a spatial scatter of the superconducting transition temperature, Tc, as long as the 211 concentration is less than 40 mol{\%}. Therefore, two different pinning centers are simultaneously active in one sample, which is also confirmed by the pinning analysis based on the scaling formalism, where we find peak positions even above 0.5 in the temperature range 60 ≥ T ≥ 93 K. The presence of the composition fluctuations is directly confirmed by means of field-cool cooling and -warming experiments in fields up to 7 T.",
keywords = "Critical currents, Flux pinning, Light rare earth 123 superconductors, Melt-processing",
author = "Koblischka, {Michael Rudolf} and Muralidhar Miryala and Masato Murakami",
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T1 - Flux pinning sites in melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu 3Oy superconductors

AU - Koblischka, Michael Rudolf

AU - Miryala, Muralidhar

AU - Murakami, Masato

PY - 2000

Y1 - 2000

N2 - (Nd0.33Eu0.33Gd0.33)Ba2Cu 3O samples are prepared with extremely fine insulating 211 particles, which are uniformly dispersed in the superconducting matrix. Even though (Nd0.33Eu0.33Gd0.33)2 BaCuO5 powders about 3 μm in diameter were added to the precursor, we have found that Gd2BaCuO5 (Gd-211) inclusions about 0.1 μm in diameter were finely distributed in the (Nd0.33Eu0.33Gd0.33)Ba2C 3Oy matrix. The formation of such fine 211 particles has not been achieved in any other bulk superconductors like YBa2Cu3O7-δ (YBCO) or NdBCO. As a function of the concentration of the 211 particles, the shape of the Jc(Ha) curves at T =77 K can be changed from a very pronounced fishtail behaviour to a plateau-like behaviour, yielding a nearly constant current density up to 2.5 T. The presence of small Gd-211 particles does not inhibit the function of flux pinning provided by composition fluctuations leading to a spatial scatter of the superconducting transition temperature, Tc, as long as the 211 concentration is less than 40 mol%. Therefore, two different pinning centers are simultaneously active in one sample, which is also confirmed by the pinning analysis based on the scaling formalism, where we find peak positions even above 0.5 in the temperature range 60 ≥ T ≥ 93 K. The presence of the composition fluctuations is directly confirmed by means of field-cool cooling and -warming experiments in fields up to 7 T.

AB - (Nd0.33Eu0.33Gd0.33)Ba2Cu 3O samples are prepared with extremely fine insulating 211 particles, which are uniformly dispersed in the superconducting matrix. Even though (Nd0.33Eu0.33Gd0.33)2 BaCuO5 powders about 3 μm in diameter were added to the precursor, we have found that Gd2BaCuO5 (Gd-211) inclusions about 0.1 μm in diameter were finely distributed in the (Nd0.33Eu0.33Gd0.33)Ba2C 3Oy matrix. The formation of such fine 211 particles has not been achieved in any other bulk superconductors like YBa2Cu3O7-δ (YBCO) or NdBCO. As a function of the concentration of the 211 particles, the shape of the Jc(Ha) curves at T =77 K can be changed from a very pronounced fishtail behaviour to a plateau-like behaviour, yielding a nearly constant current density up to 2.5 T. The presence of small Gd-211 particles does not inhibit the function of flux pinning provided by composition fluctuations leading to a spatial scatter of the superconducting transition temperature, Tc, as long as the 211 concentration is less than 40 mol%. Therefore, two different pinning centers are simultaneously active in one sample, which is also confirmed by the pinning analysis based on the scaling formalism, where we find peak positions even above 0.5 in the temperature range 60 ≥ T ≥ 93 K. The presence of the composition fluctuations is directly confirmed by means of field-cool cooling and -warming experiments in fields up to 7 T.

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