High Temperature Acoustic Anomalies In Pmn-Psn Solid Solution

We present an acoustic study of 0.55 PbMg1/3Nb2/3O3 - 0.45 PbSc1/2Nb1/2O3 relaxor ferroelectric solid solution in a wide temperature range, from 150 to 750 K. The longitudinal acoustic wave velocity and attenuation were measured by the ultrasonic pulse-echo technique at frequency 10 MHz. The strong anomalies observed in the longitudinal sound velocity and attenuation versus temperature were found to correlate with the temperature range of the relaxor ferroelectric state. Attenuation peaks were observed at characteristic temperatures of relaxors, i.e., at T-B (Burns temperature) and T* (an additional significant temperature). The results are compared with the acoustic behavior of PbMg1/3Nb2/3O3.