Dielectric properties and phase transition behavior of xPMN-(1-x)PZT ceramic systems

The dielectric properties and phase transition behavior of the pseudo-ternary xPb(Mg1/3Nb2/3)O-3-(1-x)Pb(Zr,Ti)O-3 solid solution system were investigated as a function of the Pb(Mg1/3Nb2/3)O-3 ( PMN) content and Ti/Zr ratio for selected compositions. The investigations have demonstrated a general trend in broadening of the phase transition and increasing diffusivity with increasing PMN content. For the morphotropic phase boundary (MPB) compositions, the dielectric permittivity maximum, its temperature (T-m) and the Curie-Weiss constant were found to decrease with increasing Mg1/3Nb2/3 concentration. When a Ti/Zr ratio was constant and equal to 53/47, temperature-dependent investigations demonstrated that the dielectric parameters involved in a modified Curie-Weiss law increase monotonically with increasing PMN content and T-m moves toward room temperature with average rate of approximate to -4.1degreesC/mol% as well. A phase transition in 0.5PMN-0.5Pb(Zr0.47Ti0.53)O-3 and 0.25PMN-0.75Pb(Zr0.60Ti0.40)O-3 ceramic systems exhibited a diffused behavior with a characteristic frequency dependence of T-m. From pyroelectric measurement, an unusual spontaneous polarization behavior at about 215 K is reported for some MPB compositions.