Temperature dependence of piezoelectric properties on Nd and V co-substituted Bi4Ti3O12 ceramics for ceramic resonator applications

The temperature dependences of the piezoelectric properties of (Bi4−yNdy)1−(x/12)(Ti3−xVx)O12 [BNTV-x, y (x = 0.01, y = 0.00–1.00)] were investigated for environmentally friendly lead-free piezoelectric ceramic resonators with low-temperature coefficients of resonance frequency, TC-f. The |TC-f| in the (33) mode improved with increasing concentration of modified Nd ions, y, and exhibited the smallest |TC-f| value of 77.4 ppm/°C at y = 0.75 (BNTV-0.75). The |TC-f| in the other vibration mode (t), was also investigated for the BNTV-0.75 ceramic, and a smaller value of 42 ppm/°C was obtained. The (t) mode of the BNTV-0.75 ceramic showed excellent piezoelectric properties: Qm = 4200, Qe max = 31 and TC-f = −49.8 ppm/°C. These properties are very similar to those of commercialized hard PZT ceramics for resonator applications. The BNTV-0.75 ceramic seems to be a superior candidate material for lead-free piezoelectric applications of ceramic resonators.