Excess of Eu in the (Nd0.33Eu0.33+xGd0.33-x)Ba2Cu3 Oy system: The way to a high irreversibility field at 77 K

M. Muralidhar, N. Sakai, Y. Wu, M. Murakami, M. Jirsa, T. Nishizaki, N. Kobayashi

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12 Citations (Scopus)


With the aim of raising the irreversibility field, we have fabricated (Nd0.33Eu0.33+xGd0.33-x)Ba2Cu3 Oy (NEG-123) bulk superconductors with x = 0.05, 0.07 and 0.1, with the addition of 0, 5 and 10 mol% of (Nd0.33Eu0.33Gd0.33)2BaCuO5 (NEG-211) secondary phase particles. The magnetization loops of all the samples measured with a SQUID magnetometer were open, even at 7 T at 77 K for H//c. The highest irreversibility field of over 14 T, as measured with a vibrating sample magnetometer, was achieved in the sample with x = 0.05 containing 5 mol% NEG-211. Dark-field transmission electron microscopy (TEM) showed a significant structural modulation in this sample and a fine twin-like substructure in the NEG-123 matrix. High-resolution TEM observation further confirmed the presence of a fine twin-like substructure, and also the presence of anti-phase boundaries. TEM and energy dispersive x-ray analyses have clarified that the chemical fluctuations in the NEG-123 matrix grow with increasing secondary phase content. The specific material structure supported by the particular matrix chemical composition is evidently a key parameter for the observed increase of the irreversibility field.

Original languageEnglish
Pages (from-to)1357-1363
Number of pages7
JournalSuperconductor Science and Technology
Issue number9
Publication statusPublished - 2002 Sept 1
Externally publishedYes

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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