ELASTIC ANOMALIES IN SR0.9NBO3 DETECTED BY A VIBRATING REED TECHNIQUE

Both the Young's modulus sound velocity (V-E) and the internal friction (Q(-1)) have been measured for a polycrystalline sample of Sr0.9NbO3 in the temperature range between 30 and 350 K. As temperature lowers from 350 K, V-E increases monotonically, then decreases at 230 K (=T-1) and exhibits a minimum at 80 K (=T-2) The overall softening of the velocity between T-1 and T-2 is about 22.0%. Furthermore, in the Q(-1)-vs.-T curve, three peaks are clearly observed around 315 K, 195 K and 55 K, respectively. The observed elastic anomalies suggest that structural phase transitions occurred successively around 230 K and 80 K.