Lattice vibrations and dielectric functions of ferroelectric SrBi{sub 2-x}Nd{sub x}Nb{sub 2}O{sub 9} bismuth layer-structured ceramics determined by infrared reflectance spectra
Infrared optical properties of SrBi{sub 2-x}Nd{sub x}Nb{sub 2}O{sub 9} (SBNN) ceramics with different Nd compositions (from 0 to 0.2) have been investigated by near-normal incident reflectance technique. The experimental spectra in the wavenumbers range of 350-1500 cm{sup -1} were analyzed using the...
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Published in | Materials research bulletin Vol. 45; no. 11 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
15.11.2010
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Subjects | |
Online Access | Get full text |
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Summary: | Infrared optical properties of SrBi{sub 2-x}Nd{sub x}Nb{sub 2}O{sub 9} (SBNN) ceramics with different Nd compositions (from 0 to 0.2) have been investigated by near-normal incident reflectance technique. The experimental spectra in the wavenumbers range of 350-1500 cm{sup -1} were analyzed using the Lorentz oscillator model for five infrared-active phonon mode observed. It is found that the frequencies of the NbO{sub 6} tilting and symmetric stretching modes linearly decrease with the Nd composition due to the octahedra distortion. The high-frequency dielectric constant varies in the range from 4.55 {+-} 0.04 to 4.80 {+-} 0.04. Owing to the contribution from the stronger electronic transitions, the real part of dielectric function Re({epsilon}) is estimated to about 4.0 in the high-frequency transparent region. |
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ISSN: | 0025-5408 1873-4227 |
DOI: | 10.1016/J.MATERRESBULL.2010.07.007 |