Domain wall motion effect on the anelastic behavior in lead zirconate titanate piezoelectric ceramics

Three undoped lead zirconate titanate (PZT) ceramics were prepared with compositions close to the morphotropic phase boundary: Pb(Zr0.50Ti0.50)O-3, Pb(Zr0.52Ti0.48)O-3, and Pb(Zr0.54Ti0.46)O-3. Internal friction Q(-1) and shear modulus G were measured versus temperature from 20 degreesC to 500 degreesC. Experiments were performed on an inverted torsional pendulum at low frequencies (0.1, 0.3, and 1 Hz). The ferroelectric-paraelectric phase transition results in a peak (P-1) of Q(-1) correlated with a sharp minimum M-1 of G. Moreover the Q(-1)(T) curves show two relaxation peaks called R-1 and R-2 respectively, correlated with two shear modulus anomalies called A(1) and A(2) on the G(T) curves. The main features of the transition P-1 peak are studied, they suggest that its behavior is similar to the internal friction peaks associated with martensitic transformation. The relaxation peak, R-1 and R-2 are both attributed to motion of domain walls (DWs), and can be analyzed by thermal activated process described by Arrhenius law. The R-2 peak is demonstrated to be due to the interaction of domain walls and oxygen vacancies because it depends on oxygen vacancy concentration and electrical polarization. However, the R-1 peak is more complex; its height is found to be increased as stress amplitude and heating rate increase. It seems that the R-1 peak is influenced by three mechanisms: (i) relaxation due to DW-point defects interaction, (ii) variation of domain wall density, and (iii) domain wall depinning from point defect clusters. (C) 2002 American Institute of Physics.