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Scientific article
English

Uniaxial birefringence in "cubic" Pb(Fe0.5Ta0.5)O3: is there a hidden symmetry breaking?

Published inFerroelectrics, vol. 172, no. 1-4, p. 277-285
Publication date1995
Abstract

The room temp. phase of the B-site disordered perovskite Pb(Fe0.5Ta0.5)O3 (PFT) was studied by single crystal x-ray diffraction and by polarized light microscopy. While pyramidal (100) growth sectors display a weak birefringence, indicating a tetragonal symmetry with an optically uniaxial pos. indicatrix, the structure of PFT crystals can be well refined in cubic space group Pm.hivin.3m, however, the introduction of disorder on the A site is necessary. In the light of the optical symmetry, the (x00) A-site disordered cubic structure was considered as a mean structure averaged over tetragonal domains, each contg. Pb displaced just towards one of the three [100]cub equiv. directions. Attempts at refinements in tetragonal symmetry and at mech. (ferroelastic) switching of domains are discussed.

Keywords
  • Crystal structure (of iron lead tantalum oxide)
  • Birefringence (uniaxial birefringence in Pb(Fe0.5Ta0.5)O3)
  • Iron lead tantalate structure uniaxial birefringence
Funding
  • Swiss National Science Foundation - 1994
Citation (ISO format)
GEDDO LEHMANN, Alessandra et al. Uniaxial birefringence in ‘cubic’ Pb(Fe<sub>0.5</sub>Ta<sub>0.5</sub>)O<sub>3</sub>: is there a hidden symmetry breaking? In: Ferroelectrics, 1995, vol. 172, n° 1-4, p. 277–285.
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Article (Published version)
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Identifiers
  • PID : unige:31178
ISSN of the journal0015-0193
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