Enhancement of the superconducting transition temperature by the Sr-substitution for Ba in (Yb,Ca)Ba2Cu3O6

Kohei Nakagawa, Yoshiki Sumino, Keon Kim, Takashi Noji, Takayuki Kawamata, Yoji Koike, Masatsune Kato

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We have investigated the effect of the Sr-substitution for Ba on the superconductivity in Yb0.6Ca0.4Ba2- ySryCu3O6 without Ochain forming the so-called Cu(1)O chain in the blocking layer. It has been found that Tc increases with increasing y even though no holes are doped through the Sr2+-substitution for Ba2+. The increase in Tc is because holes doped by the Ca-substitution for Yb are more likely supplied to the superconducting Cu(2)O2 plane than the blocking layer of Cu(1) owing to the contraction of the Cu(2)O2 plane through the substitution of smaller Sr2+ for larger Ba2+. The highest Tc onset = 73 K observed for y(Sr) = 0.6 is greatly higher than the previous record of Tc onset = 50 K in (RE,Ca)Ba2Cu3O6 (RE: rare-earth element). The reason why it is lower than ∼90 K for REBa2Cu3O7 is the low hole-concentration in the Cu(2)O2 plane.

Original languageEnglish
Pages (from-to)38-41
Number of pages4
JournalPhysica C: Superconductivity and its applications
Publication statusPublished - 2019 Sep 15


  • Cuprate superconductor
  • Elemental substitution
  • Hole concentration
  • RE-123 structure
  • Superconducting transition temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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