Structural, dielectric and Raman scattering studies of (1−x)PbMg_1/3Nb_2/3O₃–xPbTiO₃ single crystals (0 ≤ x ≤ 0.38)

Abstract

The X-ray powder diffraction, dielectric and Raman studies of the (1 − x) PbMg_1/3Nb_2/3O₃–xPbTiO₃ (0 ≤ x ≤ 0.38) single crystals were performed in a wide temperature range. The results of these complementary studies revealed that with the increase in PT content, the relaxor behaviour transforms into the ferroelectric one and a sequence of different structural phase transitions occur. On the base of the structural and dielectric results the phase diagram was determined. In addition, these results were used as a base for the group theory analysis and interpretation of the observed Raman spectra. The Raman spectra were deconvoluted using the independent damped oscillator model. From this model the temperature dependencies of the wavenumbers, reduced intensities and line widths were determined.

Keywords:

• Ferroelectric relaxors
• PMN–PT
• X-ray diffraction
• Dielectric properties
• Raman scattering

Acknowledgements

The paper was financially supported by the State Committee for Scientific Research (KBN) under grant 2POB8 064 25 in the years 2003–2006.