Modeling of Defects in Ceramic Oxides YAG

Abstract

Native point defects in Y3Al5O12 (YAG) were studied in the framework of the pair-potential approximation coupled with the shell model description of the lattice ions. For the perfect lattice, a new set of potential parameters were obtained which reproduce structure, elastic and dielectric constants of YAG very well. The calculated formation energies for native point defects predict that the antisite disorder is preferred over the Frenkel and Schottky like disorder in YAG. The calculated value of the distortion caused by the antisite Y sub Al are in excellent agreement with the EXAFS measurements. In non-stoichiometric YAG, the calculated reaction energies indicate that excess Y2O3 or Al2O3 is likely to be accommodated by the formation of antisite rather than vacancies in the lattice.

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Document Details

Document Type
Technical Report
Publication Date
Jan 18, 1998
Accession Number
ADA337444

Entities

People

  • Ravi Pandey

Organizations

  • Michigan Technological University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force
  • Aluminum Oxides
  • Chemistry
  • Crystal Chemistry
  • Crystal Lattice Vibrations
  • Crystal Lattices
  • Crystals
  • Dielectric Permittivity
  • Diffraction
  • Diffusion Coefficient
  • Distortion
  • Equations
  • Garnet
  • Impurities
  • Materials
  • Point Defects
  • Yttrium

Fields of Study

  • Materials science
  • Physics

Readers

  • Calculus or Mathematical Analysis
  • Materials Science and Engineering.