Morphotropic Phase Boundary of 0.875Pb(ZrxTi1-x)O3-0.125Pb (Mg1/3Nb2/3)O3 Ceramics

Effects of Zr/Ti ratios on phase formation and electrical properties of ceramics in 0.875Pb(ZrxTi1-x)O-3-0.125Pb(Mg1/3Nb2/3)O-3 or PZT-PMgN (with x = 0.46, 0.48, 0.50, 0.52, and 0.54) system, prepared by a solid state reaction technique, have been investigated in order to identify the morphotropic phase boundary (MPB) composition. With XRD analysis, the crystal structure of dense specimens appeared to change gradually from tetragonal to rhombohedral with increasing Zr content. The dielectric properties measurements showed a maximum dielectric constant (E-max) at x = 0.50, while the transition temperature (T-max) decreased with increasing Zr content. In addition, the polarization-electric field (P-E) hysteresis loops of the ceramic systems also changed significantly with the Zr content, in which the remnant polarization (P-r) reached maximum value at x = 0.50. The results clearly showed the significance of Zr/Ti ratio in controlling the phase formation and electrical properties of the PZT-PMgN ceramic system.