Synthesis and crystal structure of the oxygen defect perovskites containing copper and tantalum

Sumio Kato, Mikio Sugai, Yozo Ohshima, Hirotsugu Takizawa, Tadashi Endo

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3 Citations (Scopus)


Perovskite-related solid solutions, Sr2-xLaxCu1-yTa1+yOz, were synthesized by solid state reaction at 1050-1080°C in air. The crystalline phases were identified by powder X-ray diffraction. Three types of crystal structure were observed including simple cubic perovskite-type, tetragonal perovskite-type and tetragonally distorted (NH4)3FeF6-type structure in which Cu2+ and Ta5+ were ordered alternatively. The average valency state of copper in these solid solutions was nearly equal to + 2. The tetragonal phases were observed in a compositional range, z ≥ 5.85, regardless of cation composition. The tetragonality (c/a) for both the perovskite-type and (NH4)3FeF6-type phases increased with increasing oxygen content. Ordering between Cu2+ and Ta5+ was not observed in the Sr-rich composition. These facts suggest that oxygen content affects the appearance of the Jahn-Teller effect of Cu2+ leading to the tetragonal distortion and that the cation on the A-site affects the ordering of the cation on the B-site.

Original languageEnglish
Pages (from-to)337-341
Number of pages5
JournalSolid State Ionics
Issue number1-4
Publication statusPublished - 1998 May 1


  • Crystal structure
  • Jahn-Teller distortion
  • Oxygen defect


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