Monitoring the ferroelectric phase transition of barium titanate ceramics via impulse excitation

Impulse excitation is a suitable tool to determine the temperature dependence of Young's modulus and to monitor the ferroelectric phase transition of unpoled barium titanate ceramics (tetragonal-to-cubic and vice versa). By measurement from room temperature to 200-300 & DEG;C and back, it is found that there is an elastic anomaly with a sharp minimum (at 120 & DEG;C during heating and 110 & DEG;C during cooling, with a completely reproducible hysteresis), below and above which Young's modulus exhibits values of 40-50 GPa and up to 90 GPa, respectively, and damping changes abruptly from values of order 0.01 to less than 0.001.