Ultrasonic investigation on high-Tc superconductor CaLaBaCu3O7−y

✍ Scribed by Liping Ma; Tingzhang Deng

• Book ID: 103945831
• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 335 KB
• Volume: 201
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(92)90493-v

✦ Synopsis

Ultrasonic measurements on a high-To superconductive CaLaBaCu3OT_y polycrystalline sample have been performed. Both the transverse and longitudinal sound velocities in the sample show an anomaly around To. The Young's Modulus, Debye temperature, Bulk modulus and Poisson's ratio were calculated; they show an anomaly near To, which is common to high-To superconducting materials. Poisson's ratio shows an anomaly in a temperature range from below Tc to well above it. Below 80 K, which is the maximum possible T~ in the CaLaBaCu307_y system, Poisson's ratio begins to increase with temperature decrease, and shows a kink near To. The ultrasonic attenuation in the sample shows a sharp peak at T¢ when Tc is 67 K. As Tc dropped to 28 K, two attenuation peaks around T¢ were observed, which is common in high-To materials. The attenuation peak below Tc may be caused by the fluctuation of normal state, which becomes less apparent as hole concentration increases. The attenuation peak above T~ may be related to microstructural change.