Temperature dependence of dielectric and piezoelectric properties of Pb(Zn1/3Nb2/3)O3-PbTiO3 piezoelectric single crystals

Temperature dependence of the dielectric and piezoelectric properties of xPb(Zn1-xNb2/1)O3-yPbTiO3 (PZNT 100x/100y) piezoelectric single crystals (PSC) was investigated to estimate the heat stability of their properties. The coupling factor rectangular Liar mode k(33)' = 81% of PZNT 91/9 decreased sharply at about 70 degreesC and then decreased gradually toward the Curie temperature, T-c. On the other hand. the k(33)' = 62% of PZNT 95.5/4.5 hardly changed Lip to 110 degreesC, although it was lower than that of PZNT 91/9 at room temperature. The degradation temperatures of the k(33)' value were roughly in agreement with the phase-transition temperature. T-rt, from rhombohedral to tetragonal. measured using the poled PZNT PSC, A large dielectric hysteresis was observed when PZNT PSC was heated to a temperature higher than the T-rt, measured Using poled PZNT PSC. Although PZNT 95.5/4.5 with reduced Ti content had a higher T-rt, the obtained piezoelectric properties were inferior to those of PZNT 91/9 near the morphotropic phase boundary (MPB), Therefore, it is necessary to design the PSC composition carefully. considering specific applications in order to achieve the optimum balance between piezoelectric property and its heat stability.