Electromechanical Testing and Modeling of a Pb(Mg_1/3Nb_2/3)O₃‐PbTiO₃‐BaTiO₃ Relaxor Ferroelectric

Abstract

Compressive prestress effects on the electrical and mechanical properties of relaxor ferroelectric materials were studied as a function of temperature for several formulations of Pb(Mg1/3Nb2/3)O3‐PbTiO3‐BaTiO3 (PMN‐PT‐BT) ceramics. Experimentally measured polarization and strain, induced by an ac electric field, decreased as compressive stress increased. Effective Young's moduli also were measured under constant dc electric fields. A significant decrease in modulus was observed with increasing field. The prestress and modulus experiments were modeled analytically using a proposed relaxor ferroelectric constitutive law. In general, excellent agreement between the model and experiments was obtained, indicating that the model accurately predicted the coupled behavior of this relaxor ferroelectric material.

A dynamics model for nonlinear electrostrictive actuators

“…The displacement output signal for this case does not consist of a single harmonic, but a packet of harmonics which are frequency multiples of the excitation frequency. Table I shows values of β and the relevant model parameters for relaxor-ferroelectrics tested by Hom et al [2] and Brown et al [7]. The chemical formulas for the compositions designated b250077, b300100, and b200120 1 are, respectively:…”

“…The displacement end condition is coupled to the induced polarization, which in turn is governed by the differential (7). The rod's other end is fixed, so:…”

“…This model is unique for electrostriction, because it has been carefully validated experimentally by Brown et al [7] with electromechanical testing on blocks of PMN-PT-BT. Fripp and Hagood [13], Regelbrugge [14], and Zvonar et al [15] have incorporated the Hom and Shankar model into a simulation of a electrostrictive actuators excited at quasi-static frequencies (< 1 KHz).…”

“…Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) relaxor-ferroelectrics [3], [4] have improved stroke (∼0.1% strain) with low hysteresis, return to zero displacement after sudden voltage removal and immunity to depoling. Practical concerns for these new ceramics are their nonlinear displacement response, prestress effects, and temperature dependency [5]- [7]. These issues imply that relaxor-ferroelectrics are not the universal replacement for PZT piezoelectrics; however, relaxor-ferroelectric devices are beginning to show their relative merit for certain applications.…”

“…Data from Hom et al[2] and Brown et al[7]. Data was measured at 1 Hz, and the exact chemical compositions are described in the text.…”