Lattice contraction and cation ordering of ZrTiO{sub 4} in the normal-to-incommensurate phase transition
It is known that microwave dielectric ZrTiO{sub 4} undergoes a normal-to-incommensurate phase transition (NICPT) near 1125{degree}C. The role of the cation ordering and its relation to the anomalous lattice contraction observed in the NICPT were studied by x-ray diffraction and Raman scattering of ZrTiO{sub 4} specimens prepared employing various cooling rates between 1250 and 1000{degree}C. It was shown that the lattice parameter b underwent a substantial change even if the long-range cation ordering was absent. Analysis of the Raman spectra indicated that the compositional fluctuation-induced line broadening was mainly responsible for the extrapolated linewidth at 0 K, suggesting that the observed lattice contraction was initiated by the local short-range cation ordering. Based on thermodynamic arguments, the anomalous lattice contraction of ZrTiO{sub 4} was attributed to a direct consequence of the gradient coupling between the two order parameters that describe a compositional modulation and a displacive modulation in the NICPT. {copyright} 2001 American Institute of Physics.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203766
- Journal Information:
- Journal of Applied Physics, Vol. 89, Issue 11; Other Information: DOI: 10.1063/1.1368871; Othernumber: JAPIAU000089000011006349000001; 073111JAP; PBD: 1 Jun 2001; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
Similar Records
Powder neutron diffraction study of ZrTiO/sub 4/, Zr/sub 5/Ti/sub 7/O/sub 24/, and FeNb/sub 2/O/sub 6/
Ag{sub 1/8}Pr{sub 5/8}MoO{sub 4}: An incommensurately modulated scheelite-type structure