Ultrasonic investigations of the layered perovskite ceramic superconducting systems

Ultrasonic measurements have been carried out on three type high T c perovskite ceramic superconductors La-Sr-Cu-O, Y-Ba-Cu-O and Bi(Pb)-Sr-Ca-Cu-O. Anomalies in both sound velocity and attenuation of the above three systems were observed. The elastic constants and the Debye temperatures were also obtained and discussed.