This work presents results of the measurements of dielectric function and ultrasonic attenuation and velocity in function of temperature in (Ba1− xSrx)TiO3 ceramics. The range of temperature investigated was 125 to 325 K. Ultrasonic measurements were performed with longitudinal and transversal waves, and frequencies between 5 and 50 MHz. For a strontium concentration x = 0.30, three anomalies were clearly observed in attenuation and velocity, associated with the existence of three structural phase transitions expected for this system. In the composition x = 0.825, the “pinching” of these three phase transitions was studied. A peak structure in the ultrasonic attenuation, not related to any ferroelectric phase transition, was also observed.
Acknowledgments
This work was partially supported by FAPESP (Brazil), PEDECIBA (Uruguay) and DARPA (USA).
Paper originally presented at IMF-11, Iguassu Falls, Brazil, September 5–9, 2005