Abstract
The multiscale dynamics of complex oxides is illustrated by pairs of mechanical
resonances that are excited in the relaxor ferroelectric K1xLixTaO3 (KLT). These
macroscopic resonances are shown to originate in the collective dynamics of piezoelectric
polar nanodomains (PND) interacting with the surrounding lattice. Their characteristic
Fano lineshapes and rapid evolution with temperature reveal the coherent interplay between
the piezoelectric oscillations and orientational relaxations of the PNDs at higher
temperature and the contribution of heterophase oscillations near the phase transition.
A theoretical model is presented, that describes the evolution of the resonances over the
entire temperature range. Similar resonances are observed in other relaxors and must
therefore be a common characteristics of these systems.