Phase transitions in Pb[(Ni_1/3Sb_2/3)_xTi_yZr_z]O₃ solid solution ceramics studied by piezoelectric measurements

The piezoelectric properties of Pb[(Ni_1/3Sb_2/3)_xTi_yZr_z]O₃ solid solution, where x+y+z = 1, x = 0.08 and y = 0.44–0.49 have been investigated in a wide temperature region using a resonance technique. The physical properties of PZT near the morphotropic phase boundary modified with the relaxor Pb(Ni_1/3Sb_2/3)O₃ have been studied. The coefficients s ₁₁, k ₃₁ and d ₃₁ have been calculated basing on the damped harmonic oscillator model of piezoelectricly vibrating sample. Several anomalies in the temperature dependence of piezoelectric coefficients within the temperature range from 300 to 600 K have been found. For y > 0.46 the coexistence of rhombohedral and tetragonal phases occurs. The observed low piezoelectric activity confirms the existence of polar regions above T _m in Pb[(Ni_1/3Sb_2/3)_xTi_yZr_z]O₃.