Correlation between the dynamics of polar nanoregions and temperature evolution of central peaks in Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 ferroelectric relaxors

Acoustic properties of Pb[(Zn1/3Nb2/3)(0.91)Ti-0.09]O-3 have been investigated in a wide temperature range. The sound velocity of acoustic phonons showed a deviation from its high-temperature linear behavior at the Burns temperature T-B similar to 730 K. Upon cooling, acoustic properties exhibited significant changes at about 550 K in polarization state and width of the central peak in addition to changes in frequency and damping of acoustic phonons. This finding suggests that, besides T-B, another intermediate characteristic temperature exists in the evolution of relaxor dynamics, which might be related to the formation of long-lived polar nanoregions and associated local strain fields. (c) 2007 American Institute of Physics.