Pressure dependence of piezoelectric properties of aPb(Mg1/3Nb2/3)O3–PbTiO3 binary system single crystal near a morphotropic phase boundary

Abstract

The piezoelectric properties of aPb[(Mg1/3Nb2/3)0.68]Ti0.32O3 binary system single crystal poled along the [001] direction in therhombohedral phase were investigated under pressures up to 400 MPa at25 °C. For the transverse electromechanical property, the differenceΔf between the resonancefr and antiresonancefrequencies fa, the Δf/fr and the electromechanical coupling coefficientk31 value in thek31 mode withhydrostatic pressure (p) became smaller because of the increase infr and the almostconstant fa with p. The k31 value decreased by 16% at 400 MPa. On the other hand, for the longitudinal electromechanical property,the Δf, theΔf/fr and thek33 valuein the k33 mode with p remained almost constant because of the almost constantfr and fa with p. The changes in the values of the elastic compliancess11E ands33E withp were found to be largefrom the changes in fr and fa with p. s11E ands33E at 400 MPa wereestimated to be 35.4 and 75.1 × 10−12 m2 N−1, respectively. A mechanical quality factorQ almost constantwith p in thek33 mode in contrast tothe large decrease in Q in the k31 mode with p in the pressure range up to 200 MPa was observed. Ak33 value almostconstant with p is considered, on the basis of the engineered domain concept, to bedue to the stable domain configuration responsible for the longitudinalk33 mode. Furthermore, the superior piezoelectric properties of the rhombohedral [001]single crystal in the vicinity of the morphotropic phase boundary compositionwere recently pointed out to come from the large shear piezoelectric constantd15 of their single domain property. The hydrostatic pressure cannot influence thepiezoelectric properties from the viewpoint of the contribution of the large shear moded15, since the uniform pressure introduces no shearing stresses. Consequently, thek33 value measured forthe k33 mode remainedalmost constant with p in the measured pressure range.