In order to study the temperature and stress dependence of Young's modulus in semiconducting barium titanate ceramics, the longitudinal sound velocity was measured at a frequency of 5 MHz in the temperature range of 20-180°C. It is striking that at temperatures above the Curie point (Tc=120°C) the sound velocity reaches values that are 10-20% higher than those at room temperature. Furthermore, a shift of the Curie point of about 2×10 -8 K/Pa is observed if uniaxial stress is applied perpendicular to the sound propagation. Both effects can be understood by means of the phenomenological theory of Devonshire.
ASJC Scopus subject areas
- Physics and Astronomy(all)