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Mössbauer Spectroscopy of Borate Glasses Containing Divalent Europium Ions
Author(s) -
Fujita Koji,
Tanaka Katsuhisa,
Hirao Kazuyuki,
Soga Naohiro
Publication year - 1998
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1998.tb02556.x
Subject(s) - europium , mössbauer spectroscopy , quadrupole splitting , boron , hyperfine structure , ionic bonding , coordination number , oxidation state , inorganic chemistry , chemistry , ion , borate glass , analytical chemistry (journal) , spectroscopy , divalent , paramagnetism , materials science , crystallography , metal , physics , organic chemistry , chromatography , quantum mechanics
Borate glasses containing 0.99–30.0 mol% EuO have been prepared under a reducing atmosphere and 151 Eu Mössbauer effect measurements have been carried out at room temperature in order to examine the chemical state of Eu 2+ ions in these glasses. Mössbauer spectra indicate that most of the europium ions are present as the divalent oxidation state. In dilute Eu 2+ ‐containing borate glasses, spectra are split due to paramagnetic hyperfine interactions in the glasses with low and high sodium contents. In concentrated Eu 2+ ‐containing borate glasses, line broadening results from the contribution of quadrupole splitting due to asymmetrical oxygen coordination around Eu 2+ and the contribution of inhomogeneous broadening due to site‐to‐site variation. The compositional dependence of isomer shift and quadrupole interaction parameter can be related to the structural changes in the borate glass. The variation of the isomer shift has a good correlation with the optical basicity of glass, and the trend can be explained in terms of the covalent admixture with 6 s character. The Eu‐O bond in the borate glasses is more ionic than that in EuTiO 3 and EuZrO 3 , where the oxygen coordination number for Eu 2+ is 12. The average coordination number for Eu 2+ is found to be 12 in all of the present glasses.