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

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

Research output: Contribution to journalArticle

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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.

LanguageEnglish
Article number022
Pages3871-3879
Number of pages9
JournalJournal of Physics C: Solid State Physics
Volume11
Issue number18
DOIs
Publication statusPublished - 1 Dec 1978

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Aluminum Oxide
Light absorption
Paramagnetic resonance
optical absorption
Alumina
aluminum oxides
Sodium
sodium
Radiation
Defects
defects
radiation
Hamiltonians
nuclei
Optical transitions
Crystal symmetry
oxygen ions
color centers
hyperfine structure
optical transition

Keywords

  • optical absorption
  • sodium beta alumina
  • EPR linewidth

Cite this

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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.",
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EPR and optical absorption studies of radiation-produced defects in sodium beta -alumina. / O'Donnell, K.; Barklie, R. C.; Henderson, B.

In: Journal of Physics C: Solid State Physics, Vol. 11, No. 18, 022, 01.12.1978, p. 3871-3879.

Research output: Contribution to journalArticle

TY - JOUR

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AU - O'Donnell, K.

AU - Barklie, R. C.

AU - Henderson, B.

PY - 1978/12/1

Y1 - 1978/12/1

N2 - 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.

AB - 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.

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