FREQUENCY DEPENDENT ELECTROSTRICTIVE EFFECT IN THE ANTIFERROELECTRIC PbZrO3 CRYSTALS

For the antiferroelectric lead zirconate crystals with one phase transition the measurements of electrostrictive deformation have been performed as a function of temperature, frequency and strength of an applied electric field in paraelectric phase (510-540 K). Polarization and strain depend strongly on frequency (40-200 Hz) of the applied electric field (2-10 kV/cm). A quadratic relation between strain x and the electric field E (x = M.E-2) is not fulfilled except in the higher frequency region. The observed frequency dependence of the electrostrictive effect for PbZrO3 were compared and discussed with previously found dielectric dispersion. The results were compared to the sample exhibiting a transient phase below T-c. At frequencies above the dispersion region (over 200 Hz) the electrostrictive coefficients Q(11) for the sample without and with the transient phase are equal to 2.10(-2) m(4)/C-2 and 1.2.10(-2) m(4)/C-2, respectively and are temperature independent.