super(57)Fe Moessbauer and DTA study of R sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) glasses (R = Li, Na)

The super(57)Fe Moessbauer spectra of xLi sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) and xNa sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) glasses (x = 0, 0.5, 1.0 and 1.5) consist of two doublets due to Fe super(II) and Fe super(III). The isomer shift indicates that Fe super(III) atoms form Fe...

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Bibliographic Details
Published in:Journal of the Ceramic Society of Japan 2008-01, Vol.116 (1353), p.637-640
Main Authors: Kurimoto, Hiroshi, Nishida, Tetsuaki, Okada, Shigeto, Yamaki, Jun-Ichi
Format: Article
Language:English
Subjects:
Ceramics
Electrical conductivity
Glass
Mossbauer spectroscopy
Quadrupoles
Slopes
Spectra
Straight lines
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Summary:The super(57)Fe Moessbauer spectra of xLi sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) and xNa sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) glasses (x = 0, 0.5, 1.0 and 1.5) consist of two doublets due to Fe super(II) and Fe super(III). The isomer shift indicates that Fe super(III) atoms form Fe super(III)O sub(4) tetrahedra or Fe super(III)O sub(6) octahedra, while Fe super(II) atoms from Fe super(II)O sub(6) octahedra. A liner relationship exists between the glass transition temperature, T sub(g), and the quadrupole splitting, Delta , of Fe super(III) atoms in the Moessbauer spectra. Slopes of the straight lines were estimated to be 460 and 370 degree C (mm s super(-1)) super(-1) in xLi sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) and xNa sub(2)O.2FeO.V sub(2)O sub(5).P sub(2)O sub(5) glasses, respectively. These results suggest that Fe super(III) atoms form oxygenpolyhedra that are intermediate between Fe super(III)O sub(4) tetrahedra and Fe super(III)O sub(6) octahedra. The electric conductivity obtained by a dc four-probe method was of the order of 10 super(-5) to 10 super(-6) S cm super(-1).
ISSN:1348-6535