Compositional Phase Separation in La2-xBaxCuOy, near the Optimum Composition for Superconductivity

Kazuyoshi Yoshimura, Hiroshi Kubota, Hiroshi Tanaka, Yumiko Date, Makoto Nakanishi, Tomohiko Ohmura, Nobuhiro Saga, Takashige Sawamura, Takashi Uemura, Koji Kosuge

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Compositional phase separation was observed in La2-xBaxCuOy near the optimum composition (a:-0.16) for superconductivity with a decisive miscibility gap by means of X-ray diffraction measurements. The phase-separated samples do not show intrinsic superconductivity. Therefore, the superconductive compound in this system is not in a chemical equilibrium state at low temperatures, but is a high-temperature phase obtained by quenching to room temperature. The critical temperature of the phase separation Tp takes a maximum value of 950°C at x~0.16, suggesting that phase instability is crucial for high-7; superconductors. The end composition of the miscibility gap in the Ba-poor composition region was found to be 0.12, which is a singular point from crystallographic and band structural standpoints.

Original languageEnglish
Pages (from-to)1114-1117
Number of pages4
Journaljournal of the physical society of japan
Volume62
Issue number4
DOIs
Publication statusPublished - Jan 1 1993
Externally publishedYes

Keywords

  • La2-xBaxCuO4
  • high-Tc superconductivity
  • phase separation

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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