EFFECT OF PHASE COEXISTENCE AT MORPHOTROPIC PHASE-BOUNDARY ON THE PROPERTIES OF PB(ZRXTI1-X)O-3 CERAMICS

The temperature variation of planar electromechanical coupling coeffic ient (k(p)) in Pb(ZrxTi1-x)O-3(PZT) ceramics near the morphotropic pha se boundary (MPB) compositions has been correlated with structural cha nges to show that the maximum electromechanical response at a given co mposition (x) is a function of temperature (T) and occurs in the tetra gonal phase field just outside the two-phase MPB region in the (x,T) p lane. This clearly disproves the hypothesis that the coexistence of rh ombohedral and tetragonal phases at MPB is responsible for the enhance ment of the electromechanical response. In fact, coexistence of the rh ombohedral phase with the tetragonal phase is shown to lead to the low ering of the electromechanical response. (C) 1996 American Institute o f Physics.