Electromechanical properties of relaxor ferroelectric lead magnesium niobate-lead titanate ceramics

In this paper, the results of a recent investigation of the dependence of the induced piezoelectric activity on temperature, electric bias field, and frequency and the electrostrictive response in the relaxor ferroelectric lead magnesium niobate-lead titanate ceramics ((1-x)(Pb(Mg_1/3Nb_2/3)O₃)- x(PbTiO₃)) at compositions below 30% PT are presented. It was observed that the electrostrictive strain at temperatures near the dielectric constant maximum T_max increases monotonically with increased PT content. For PMN:PT at compositions near 30% PT, the electrostrictive strain under a 10 kV/cm electric field can reach about 0.15% with very little hysteresis. An exceptionally large piezoelectric response with an effective piezoelectric d₃₃ coefficient in the electric field induced state of over 1,800 pC/N could be achieved for selected PMN:PT compositions and electric bias fields.