Temperature dependence of electromechanical properties of PLZT x/57/43 ceramics

The compositions of lead lanthanum zirconate titanate PLZT [Pb(Zr0.57Ti0.43)O3 + x at% of La, where x = 3, 5, 6, 10 and 12] have been synthesized using mixed oxide route. The temperature dependent electromechanical parameters have been determined using vector impedance spectroscopy (VIS). The charge constant d 31 and elastic compliance s 11 show a peak in all the samples at a temperature T mt much below the ferroelectric — paraelectric transition temperature, whereas the series resonance frequency f s shows a dip at these temperatures. The Poisson’s ratio σ E increases with temperature T showing a broad peak at a temperature higher than T mt . The voltage constant g 31 decreases and the planar coupling coefficient K p remains constant up to half of the T mt and then falls sharply with T. Half of the T mt can, therefore, be used for specifying the working temperature limit of the piezoceramics for the device applications.