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

Piezoelectric properties of Na0.5Bi0.5TiO3 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 degreesC. For the first time it has been found that a piezoelectric signal connected with the tensor component d(33) is observed up to 280 degreesC. This corresponds to earlier neutron and x-ray diffraction data on the point of transition from rhombohedral to tetragonal symmetry.