PZT phase diagram determination by measurement of elastic moduli

The aim of the present paper is to investigate the PZT phase diagram and to examine the phase transitions occurring in the low temperature range near the morphotropic phase boundary by using measurement of elastic moduli. The phase transitions are also studied by XRD measurements as a function of temperature. XRD patterns as a function of temperature let us to follow the evolution of lattice parameters and so the determination of phase transitions. Phase transitions identified by Young's and shear modulus anomalies M1 and M2 are in accordance with those found by XRD studies and correspond, respectively to the Curie transition—between cubic paraelectric phase and tetragonal ferroelectric phase—and to the morphotropic transition—between both ferroelectric tetragonal and rhombohedral phases or from tetragonal to monoclinic phase. Finally a revisited version of PZT phase diagram is proposed.