The kinetics of the local compositional changes at the ferroelectric-antiferroelectric interphase boundaries in lead-lanthanum titanate-zirconate solid solutions

摘要

The process of local decomposition of lead-lanthanum zirconate-titanate solid solution in the vicinity of the interphase boundaries separating domains of coexisting ferroelectric and antiferroelectric phases has been investigated. The kinetics of the local decomposition of the solid solution containing 6 at.% La, 73 at.% Zr, and 27 at.% Ti in the process of ageing of samples quenched down to room temperature from the paraelectric phase is studied. The mechanisms that define the kinetics of the process of attainment of the equilibrium state of coexisting domains of ferroelectric and antiferroelectric phases are analysed. It is demonstrated that there are two main mechanisms determining the kinetics of establishing of the equilibrium inhomogeneous chemical composition of a solid solution. The slower mechanism is determined by the diffusion of the oxygen vacancies, the nonequilibrium concentration of which was created during the annealing at the temperatures above the Curie temperature. The faster process is determined by the cation diffusion caused by the local mechanical stresses in the vicinity of the interphase boundaries. The equilibrium structure establishes during a time interval of not less than 120 h.