Correlation between the dynamics of polar nanoregions and temperature evolution of central peaks in Pb[(Zn_(1/3)Nb_(2/3))_(0.91)Ti_(0.09)]O_3 ferroelectric relaxors

摘要

Acoustic properties of Pb[(Zn_(1/3)Nb_(2/3))_(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 ～ 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.