Low-temperature synthesis of the (Ba, Sr, Ca)-Cu-O system from hydroxometallate precursors

Ichiro Nagai, Masatsune Kato, Yoji Koike

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2 Citations (Scopus)


Alkaline-earth cuprates of Sr1-xCaxCuO2 and (Sr1-xBax)2CuO3+y have been synthesized at temperatures as low as 400-500°C by thermal decomposition of hydroxometallate precursors of Sr1-xCaxCu(OH)4 · H2O and (Sr1-xBax)2Cu(OH)6 · H2O, respectively. In the first step of the synthesis, we succeeded in obtaining new hydroxometallate precursors Sr1-xCaxCu(OH)4 · H2O and (Sr1-xBax)2Cu(OH)6 · H2O through precipitation in a highly concentrated NaOH solution. In the second step, the hydroxometallate precursors were heated at various temperatures. In the case of Sr1-xCaxCu(OH)4 · H2O, the ambient-pressure phase of SrCuO2 was obtained at 500°C in flowing N2 gas. In the case of (Sr1-xBax)2Cu(OH)6 · H2O, three kinds of phases of (Sr1-xBax)2CuO3+y with different excess oxygen content y were obtained at 400°C: y approx. 0, approx. 0.1 and approx. 0.3-0.5. It has been found that the excess oxygen content y tends to increase with increasing Ba content x, with increasing oxygen partial pressure during the heat treatment and with decreasing heat-treatment 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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