Nonlinear dielectric response of relaxor PLZT ceramics in a dc bias electric field

The temperature dependences of the first, ε1, and the third, ε3, harmonic dielectric responses have been simultaneously measured in 9/65/35 PLZT ceramics in a dc bias electric field, higher than the critical field. Additional peaks in both, ε1 and ε3, superimposed on the broad dispersive relaxor background were observed, indicating induced ergodic relaxor to ferroelectric phase transition. It is shown that the dielectric nonlinearity a3=ε3ε14, as predicted by the spherical random bond-random field model of relaxor ferroelectrics, indeed monotonously decreases when approaching the relaxor to ferroelectric transition temperature.