Dielectric dispersion near the morphotropic phase boundary of 0.64PMN-0.36PT ceramics

A near morphotropic phase boundary (MPB) composition of PMN-PT ceramic, 0.64Pb(Mg1/3Nb2/3)O3-0.36PbTiO3, has been synthesized for various piezoelectric, ferroelectric and dielectric applications. The relaxation mechanisms and dielectric characteristics of this solid solution have been investigated with dielectric spectroscopy measurements in the frequency range of 20 Hz–2 MHz. The dielectric properties have shown distinct and prominent Debye type relaxation at the temperatures corresponding to the ferroelectric phase. The peak in dielectric loss parameter has been found to be dominated by the dc conductivity in paraelectric phase. The experimentally obtained values of various parameters have been found in agreement with the values obtained by fitting of the experimental data in Debye model. An excellent agreement of the results with Debye distribution of relaxation times was obtained with the distribution parameter α showing minima around the ferro-to para-electric phase transition. Different activation energies of the relaxation time have been observed in the ferroelectric and paraelectric phases. An average relaxation time has been found to decrease from ∼10−3 s to ∼10−6 s with the increasing temperatures.