Phase transition and domain pinning effect of Sr²⁺-doped hard PZT ceramics

Pb_1-xSr_x(Zr_0.53Ti_0.47)_0.99O₃ + 1 mol%Fe₂O₃ (PSZTF-100x) (x = 0.05–0.20) ceramics were prepared by solid state reaction method. With the increase of Sr content, the crystal structure of the ceramics changed from tetragonal phase to the coexistence of tetragonal phase and rhombohedral phase, then to pseudo-cubic phase. Associated with the crystal structure change, the phase transition temperature (T_C) decreased, the diffuseness at T_C increased and the domain pinning strength reduced. For the poled ceramics, PSZTF-10 ceramics show the best properties including large d₃₃ (310 pC/N), very low tanδ (0.29%), large Q_m (870) and nearly hysteresis-free strain, which suggest that PSZTF-10 ceramics are good candidates for high precision positioning application.