Results on a lanthanum-modified, lead zirconate-titanate have revealed
(1) pressure-induced crossover from normal ferroelectric- (nFE-) to-r
elaxer (R) behavior; (2) the continuous evolution of the dynamics of t
he relaxation process; (3) a spontaneous R-to-nFE transition at a temp
erature well below the dynamic glass temperature of the R phase; and (
4) the vanishing of this transition with pressure at a critical point.
These results can be understood in terms of a large decrease in the c
orrelation radius among polar nanodomains-a unique property of soft fe
rroelectric phonon mode systems.