EPR and optical absorption studies of radiation-produced defects in sodium beta -alumina

K. O'Donnell, R. C. Barklie, B. Henderson

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24 Citations (Scopus)

Abstract

The EPR and optical absorption spectra of X-ray irradiated single crystal of Na beta -alumina have been examined. The most prominent absorptions are tentatively ascribed to an F+ centre at the O(5) oxygen ion site in the conduction plane. To this defect the authors assign an axially symmetric EPR spectrum which shows a resolved hyperfine structure due to interaction of the single unpaired spin with two equivalent 27Al(I=5/ 2) nuclei. The measured spin-Hamiltonian parameters are g/sub ///=2.0076(2), gperpendicular to=2.0032(2), A/sub ///=1.665(2) mT, Aperpendicular to=1.617(2) mT, the defect symmetry axis coinciding with the crystal c axis. From the EPR linewidth it is inferred that the hyperfine interaction with three equivalent 23Na nuclei is of order 0.2 mT. This defect is also optically active having a strongly polarised s to pz transition with mean energy EF=4.15(5) eV. The corresponding s to px,y optical transitions are not observed in the range of photon energies from 4.2-6.8 eV.

Original languageEnglish
Article number022
Pages (from-to)3871-3879
Number of pages9
JournalJournal of Physics C: Solid State Physics
Volume11
Issue number18
DOIs
Publication statusPublished - 1 Dec 1978

Keywords

  • optical absorption
  • sodium beta alumina
  • EPR linewidth

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