Formation of a cluster structure in the PbZr$_{1-x}$Ti$_{x}$O$_{3}$ system

Microdeformations of the crystal lattices in the phombohedral and tetragonal regions of the PbZr$_{1-x}$Ti$_{x}$O$_{3}$ phase diagram have been calculated and their dependences on the titanium concentration have been constructed. Based on an analysis of these dependences, it has been concluded that tetragonal-phase clusters form in the range 0.11 $<x<$ 0.12 and rhombohedral-phase clusters form in the range 0.725 $<x<$ 0.750.