Crystal structure analyses of the pyrochlore and fluorite-type Zr2Gd2O7 and anti-phase domain structure

Toshihiro Moriga, Akira Yoshiasa, Fumikazu Kanamaru, Kichiro Koto, Masahiro Yoshimura, Shigeyuki Somiya

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Abstract

The detailed structure investigations of Zr2Gd2O7 with pyrochlore- and fluorite-type structures have been carried out by X-ray single crystal method at room temperature. The bond distances between cations and oxide ions versus the site population for cations reasonably support that the fluorite phase is made up of the structure with microdomains of the pyrochlore. Sharp fundamental and diffuse superstructure reflections of the pyrochlore are interpreted assuming that anti-phase domain boundaries lie parallel to the &{211} and that domain sizes are not uniform. It should be proposed that the layers composed of the 48f site oxide ions are anti-phase boundaries. The probability density function maps and effective one-particle potentials of the pyrochlore structure reveal that the magnitudes of anharmonic thermal motions for the 48f site oxide ions are large toward the unoccupied 8b site. Compared to the s-pyrochlore phase (with sharp superstructure reflections), the 48f site oxide ions of the d-pyrochlore (with diffuse superstructure reflections) and fluorite phases have larger temperature factors and gentler potential curves. This is due to that the anti-phase domains are coherent each other and that their electron density distributions are the averages of individual domains.

Original languageEnglish
Pages (from-to)319-328
Number of pages10
JournalSolid State Ionics
Volume31
Issue number4
DOIs
Publication statusPublished - 1989 Jan

All Science Journal Classification (ASJC) codes

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

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