Mesoscopic nanostructures and long-time relaxation processes in ferroelectrics with coexisting ferroelectric and antiferroelectric phases*

Presentation contains results of experimental study of the kinetics of mesoscopic segregate structures formed in the vicinity of interphase domain boundaries separating the domains of the coexisting ferroelectric and antiferroelectric phases in two series of the lead zirconate titanate based solid solutions in which the isovalent complex (La$_{0.5 }$Li$_{0.5})^{2+}$ or the La$^{3+}$ ions are substituted for lead. These systems of solid solutions possess an extended interval of compositions for which the inhomogeneous state of coexisting ferroelectric and antiferroelectric domains is energetically favorable in comparison with homogeneous ferroelectric and antiferroelectric phases. The mechanisms that control the kinetics of formation of the segregates are investigated and compared for these two series of solid solutions