Kinetics of ordering in gadolinium zirconate: an unusual oxygen ion conductor

Sossina M. Haile*, Scott Meilicke

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations

Abstract

Gadolinium zirconate, Gd2Zr2O7, undergoes an order-disorder transition at approx.1550°C, transforming from a defect fluorite structure (Fm3m) to a pyrochlore structure (Fd3m). Both cations and anions are ordered in the low-temperature, pyrochlore structure. In order to understand the interplay between anion and cation order parameters and ordering rates, the transformation kinetics of Gd2Zr2O7 have been examined via X-ray diffraction. Gadolinium zirconate is of particular interest because the oxygen ion conductivity of the ordered phase is significantly greatly than that of the disordered phase, in contrast to virtually every other known solid electrolyte. This difference in conductivity has provided a second technique for characterizing the transformation kinetics: in situ A.C. impedance spectroscopy. Results of the X-ray diffraction showed the growth of superstructure peak intensity to follow an apparent (time) 1/2 dependence, rather than that expected from a nucleation and growth model. The impedance spectroscopy measurements, on the other hand, showed the conductivity to increase linearly with time. These results suggest the transition is second order in nature.

Original languageEnglish (US)
Pages (from-to)599-604
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume398
StatePublished - Jan 1 1996
EventProceedings of the 1995 MRS Fall Meeting - Boston, MA, USA
Duration: Nov 26 1995Dec 1 1995

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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