The piezoelectric effect in Na0.5Bi0.5TiO3 ceramics

Piezoelectric properties of Na 0.5 Bi 0.5 TiO 3 ceramics have been investigated over a broad temperature range using a resonance technique. The thermal behaviours of the piezoelectric tensor coefficients d 31 , d 33 and d 15 confirm that there is a distinct phase transformation at 200 °C. For the first time it has been found that a piezoelectric signal connected with the tensor component d 33 is observed up to 280 °C. This corresponds to earlier neutron and x-ray diffraction data on the point of transition from rhombohedral to tetragonal symmetry.