Possible bulk inhomogeneity of superconductivity in Y 1-xCaxBa2Cu3O7-δ (x = 0-0.2)

S. Chamura, T. Adachi, Y. Tanabe, Y. Koike

Research output: Contribution to journalArticlepeer-review


In order to investigate the possible inhomogeneity of superconductivity, measurements reflecting bulk properties of a sample, namely, magnetic susceptibility, χ, and specific heat have been carried out for Y 1-xCaxBa2Cu3O7-δ with x=0.1 and 0.2. From the χ measurements, both the absolute value of χ at 2 K on field cooling, |χ2K|, reflecting the superconducting (SC) volume fraction and Tc have been found to increase systematically with an increase of the hole concentration in the CuO2 plane, p, for each x. From the specific heat measurements, on the other hand, it has been found that the residual Sommerfeld constant, γ0, is not zero but has a finite value even in the SC state. Moreover, γ0 in each x shows a p dependence similar to that observed in La2-xSrxCuO4. These results strongly suggest that a phase separation into SC and normal-state regions occurs at least in the underdoped regime of Y1-xCaxBa2Cu 3O7-δ irrespective of the Ca content, and is a generic feature in the high-Tc cuprates.

Original languageEnglish
Pages (from-to)S199-S200
JournalPhysica C: Superconductivity and its applications
Issue numberSUPPL.1
Publication statusPublished - 2010 Dec


  • Magnetic susceptibility
  • Phase separation
  • Specific heat
  • YBaCuO

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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