Influence of domain walls on piezoelectric and electrostrictive properties of PMN-PT (65/35) ceramics

Polarization and strain measurements on lead magnesium niobate-lead titanate ceramic (0.65PMN-035PT) are performed. Quasi-static P(E) and S(E) loops and dynamic measurements of the dielectric constant, piezoelectric d33 and electrostrictive Q11 coefficients are made. The relation between piezoelectricity and electrostriction in polydomain materials is discussed. The relation d33 = 2ee0Q11P0 which is true for monodomain materials is not verified in the case of ceramics. The influence of domain walls motion on dielectric constant and piezoelectric coefficient is shown. The calculation of the ratio of 180° and 90° domains in the sample is made using the characteristic values related to the hysteresis loops and shows the larger amount of 180° domains in this material.