Ultrasonic attenuation and velocity in BiSrCaCuO high Tc superconductor

Abstract The temperature dependences of ultrasonic attenuation and velocity in high Tc superconductor BiSrCaCuO were measured between 50k and 280k, using longitudinal and shear waves. Ultrasonic attenuation anomalies were found at 87k, 120k, 240k and 250k for longitudinal wave, and at 240k for shear wave; ultrasonic velocity anomalies were found at 87k, 240k for longitudinal wave and at 87k, 170k and 240k for shear wave. It was suggested that there is a second order phase transition at 240k.