Linear and nonlinear dielectric constant as function of bias electric field in relaxor materials

The quasistatic linear and nonlinear dielectric constants εS in 9/65/35 PLZT ceramics and PMN crystal were investigated by means of the charge accumulation technique and by monitoring the first, ε1, and the third, ε3, harmonic response. The zero field cooled and field cooled static susceptibilities show a crossover from a nonergodic relaxor to inhomogeneous ferroelectric behaviour. At electric fields above the critical value contribution from the saturated spontaneous polarization was observed. The temperature dependence of the total third order nonlinear response was determined in 9/65/35 PLZT ceramics.