Low-temperature synthesis of Sr1-xCaxCuO2 from hydroxide precursor

Masatsune Kato, Ichiro Nagai, Yoji Koike

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4 Citations (Scopus)

Abstract

The alkaline-earth copper oxides Sr1-xCaxCuO2 (0 ≤ x ≤ 1) have been synthesized in flowing gas of N2 or O2 by thermal decomposition of hydroxide precursors Sr1-xCaxCu(OH)4 · H2O. In the first step, we have succeeded in obtaining hydroxide precursors Sr1-xCaxCu(OH)4 · H2O with 0 ≤ x ≤ 1 in the form of a precipitation in a highly concentrated NaOH solution. In the second step, namely, in the process of thermal decomposition, the hydroxide precursors have been found to be decomposed into an amorphous condition at a temperature as low as 200°C. The ambient-pressure phase of SrCuO2 is obtained by heating the hydroxide precursors for 12 h at 500°C and 700°C in flowing gas of N2 and O2, respectively. The reaction temperature is much lower than the 1000°C in flowing gas of O2 in the conventional solid-state reaction method. With increasing x up to 0.7, the temperature at which the ambient-pressure phase of Sr1-xCaxCuO2 appears increases in flowing gas of both N2 and O2. The so-called infinite-layer compound of Sr1-xCaxCuO2 is obtained in a narrow range of x around 0.9 at ∼ 1000°C in flowing gas of O2, which is similar to the result in the conventional solid-state reaction method. For x ∼ 1, the ambient-pressure phase of Ca1-xCuO2 (y ∼ 0.15) appears in the temperature range between 600°C and 800°C only in flowing gas of O2.

Original languageEnglish
Pages (from-to)275-281
Number of pages7
JournalSolid State Ionics
Volume108
Issue number1-4
DOIs
Publication statusPublished - 1998 May 1

Keywords

  • (Sr,Ca)CuO
  • Hydroxide
  • Low temperature synthesis
  • Thermal analysis
  • X-ray diffraction

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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