Structural properties of Sr{sub 0.61}Ba{sub 0.39}Nb{sub 2}O{sub 6} in the temperature range 10-500 K investigated by high-resolution neutron powder diffraction and specific heat measurements
- Laboratory for Neutron Scattering, ETH and PSI, CH-5232 Villigen, PSI (Switzerland)
- Institut fuer Mineralogie, University at Cologne, D-50674 Cologne(Germany)
- Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 18221 Prague 8 (Czech Republic)
- Fachbereich Physik, University of Osnabrueck, D-49069 Osnabrueck (Germany)
We report high-resolution neutron powder diffraction on Sr{sub 0.61}Ba{sub 0.39}Nb{sub 2}O{sub 6} in the temperature range 15-500 K. The results indicate that the low-temperature anomalies (T{<=}100 K) observed in the dielectric dispersion are due to small changes in the incommensurate modulation of the NbO{sub 6} octahedra, as no structural phase transition of the average structure was observed. This interpretation is supported by specific heat measurements, which show no latent heat, but a glass-like behavior at low temperatures. Furthermore, we find that the structural changes connected with the ferroelectric phase transition at T{sub c}{approx_equal}350 K start already at 200 K, explaining the anisotropic thermal expansion in the temperature range 200-300 K observed in a recent x-ray diffraction study.
- OSTI ID:
- 20853734
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 74, Issue 13; Other Information: DOI: 10.1103/PhysRevB.74.134103; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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