Domain wall contribution to dielectric and piezoelectric responses in O.65Pb(Mg_(1/3)Nb_(2/3))-O.35PbTiO_3_ ferroelectric ceramics

摘要

In this paper, the contribution of the domain walls motion to the dielectric and piezoelectric responses for the 0.65Pb(Mg_(l/3)Nb_(2/3))O_3-0.35PbTiO_3 system is investigated. A monotonically increasing temperature dependence of the dielectric permittivity is observed from very low temperatures up to the ferroelectric_paraelectric phase transition temperature. It is verified that the major contribution to dielectric response at room temperature is from the extrinsic effect. A linear dependence of the permittivity with the amplitude of the ac applied electric field is verified from the nonlinear dielectric measurement. Rayleigh's model is used to quantitatively evaluate the dielectric response, leading to similar behaviour of the typical soft PZT. On the other hand, direct piezoelectric response also displays a Rayleigh-type behaviour. Piezoelectric measurements show in the entire investigated dynamic stress range a decrease in the piezoelectric response with both increase in frequency of the applied dynamic stress and increase in the pre-stress on the samples.