Abstract:
The infrared reflectivity of Cd2Nb2O7 single crystal was studied in the temperature interval of 10-540 K, together with complementary dielectric measurements. A ferroelectric soft mode was revealed above the ferroelectric phase transition at T c = 196 K coupled with a central-mode type dispersion in the near-millimetre range. This proves the mixed displacive and order-disorder nature of the transition. Below T c many new modes were detected due to lowering of the symmetry, especially below the previously suggested incommensurate transition at 85 K. Discussion of the possible phase transitions based on symmetry considerations is presented with the conclusion that the ferroelectric transition is proper with the F1u symmetry of the order parameter, whereas the intermediate ferroelastic transition is improper and triggered by the coupling with the ferroelectric order parameter.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received 17 July 2000
Rights and permissions
About this article
Cite this article
Buixaderas, E., Kamba, S., Petzelt, J. et al. Phase transitions sequence in pyrochlore Cd2Nb2O7 studied by IR reflectivity. Eur. Phys. J. B 19, 9–16 (2001). https://doi.org/10.1007/s100510170344
Issue Date:
DOI: https://doi.org/10.1007/s100510170344