Temperature Dependence of Piezoelectric Constant of 0.5PbNi1/2Nb2/3O3–0.5Pb(Zr, Ti)O3 Ceramics in the Vicinity of Morphotropic Phase Boundary

Abstract

The temperature dependence of the piezoelectric constant of PbNi1/2Nb2/3O3–PbTiO3–PbZrO3 50/x/50-x ceramics (PNN–PT–PZ) in the vicinity of the morphotropic phase boundary (MPB) induced with dc bias was investigated. The maximum value of the transverse piezoelectric constant, d31, of the ceramic of PNN–PT–PZ 50/34/16 was 400 pm/V at room temperature and 600 pm/V at around 80°C. In the tetragonal ceramic of PNN–PT–PZ 50/35/15, d31 exhibited a maximum with increasing temperature, and the position of MPB did not change under dc bias. In the rhombohedral ceramics of PNN–PT–PZ 50/34/16 and 50/33/17, d31 also exhibited a maximum with increasing temperature, because the ceramics underwent a phase transition from rhombohedral to tetragonal. These maximum positions of d31 shift to higher temperatures with increasing dc bias in the rhombohedral ceramics only. Based on the relationship between d31 and temperature under bias, a phase diagram for 0.5PbNi1/2Nb2/3O3–0.5Pb(Zr, Ti)O3 ceramics under dc bias is proposed. The ratio of the tilt of the MPB to temperature under dc bias is smaller than that under no dc bias.