Investigation into the structure of ceramic LiNaTaNbO solid solutions by X-ray analysis and Raman spectroscopy.

The structure of ceramic solid solutions LiNaTaNbO has been investigated by full-profile X-ray diffraction analysis and Raman spectroscopy. It is shown that their structure for all x values is similar to the NaNbO structure. The structure of NaTaNbO solid solutions ( x = 0) is characterized by the sp. gr. Pbcm, and the structure of LiNaTaNbO solid solutions with x = 0.05, 0.1, and 0.16 is characterized by the sp. gr. P2 ma. The unit-cell parameters decrease with an increase in x. At x = 0, doubled values of the parameter c and, correspondingly, the unit-cell volume are observed in the antiferroelectric phase. This fact is confirmed by the form of the vibrational spectrum in the region of stretching modes of oxygen atoms along the polar axis. [ABSTRACT FROM AUTHOR]