Piezoelectric and dielectric properties of Fe2O3-doped 0.57Pb(Sc1/2Nb1/2)O3-0.43PbTiO3 ceramic materials

Abstract

High-power piezoelectric materials are presently being extensively developed for applications such as ultrasonic motors and piezoelectric transformers. In this study, the piezoelectric and dielectric properties of Fe2O3-doped 0.57Pb(Sc1/2Nb1/2)O3-0.43PbTiO3 (hereafter 0.57PSN-0.43PT), which is the morphotropic phase boundary composition of the PSN-PT system, were investigated. The maximum dielectric constant (ε33/ε0 = 2551) and the minimum dielectric loss (tanδ = 0.51%) at room temperature were obtained at Fe2O3 additions of 0.1 wt% and 0.3 wt%, respectively. The temperature dependence of the dielectric constant and the dielectric loss was measured between room temperature and 350°C. With the addition of Fe2O3, the piezoelectric constant d33 and electromechanical coupling factor kp were slightly decreased, but the mechanical quality factor Qm was significantly increased. The highest mechanical quality factor (Qm = 297) was obtained at 0.3 wt% Fe2O3, which is 4.4 times higher than that of nondoped 0.57PSN-0.43PT ceramics. The P-E and S-E loops of the samples at room temperature and at 1.0 Hz were measured at the same time using an automated polarization measuring system. ©1999 Publication Board, Japanese Journal of Applied Physics.