Transmission electron microscopy study of polymorphism in barium gallate BaGa2O4

H. Lemmens, S. Amelinckx, G. Van Tendeloo, A. M. Abakumov, M. G. Rozova, E. V. Antipov

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Polymorphism in barium gallate BaGa2O4 was studied using electron diffraction and high resolution electron microscopy. Three modifications of BaGa2O4 with structures closely related to the high-temperature α-form were observed. The phase transitions from γ-BaGa2O4 (aγ = 18.6143(2)Å = 2√3aα, cγ = 8.6544(1) Å = cα, S.G. P63) to β-BaGa2O4 (aβ = 2aα, Cβ = cα S.G. P6 3) and to the new δ-polymorph having a monoclinic structure (aδ = cα, bδ = 2a α + bα, cδ = 2b α and β ≈ 92°, S.G. P21/c) were induced by electron beam irradiation. High resolution electron microscopy (HREM) observations allow to establish the close similarity between the structures of δ-BaGa2O4 and β-SrGa2O4. The γ→β and β-δ transitions involve a rearrangement of oxygen atoms in the BaO layers together with a tilting distortion of the tetrahedral framework. The microstructure of the δ-phase is characterised by the presence of numerous translation and orientation domains.

Original languageEnglish
Pages (from-to)653-670
Number of pages18
JournalPhase Transitions
Volume76
Issue number7
DOIs
Publication statusPublished - 2003
Externally publishedYes

Keywords

  • Barium gallate
  • Phase transition
  • Polymorphism
  • TEM

Fingerprint

Dive into the research topics of 'Transmission electron microscopy study of polymorphism in barium gallate BaGa2O4'. Together they form a unique fingerprint.

Cite this