Title :
Gigahertz ultrasound in single crystal superconducting YBa2 Cu3O7
Author :
Golding, Brage ; Haemmerle, W.H. ; Schneemeyer, L.F. ; Waszczak, J.V.
Author_Institution :
AT&T Bell Lab., Murray Hill, NJ, USA
Abstract :
Anisotropic sound propagation at 1 GHz in single-crystal YBa2 Cu3O7 is described. Longitudinal phonons have been studied from 0.01 K to 300 K, with emphasis on the temperature region near the superconducting transition Tc at 88 K. A discontinuous sound velocity is observed at Tc for propagation parallel and perpendicular to the c axis. Strain derivatives of Tc are evaluated using mean field theory. Below 1 K the temperature-dependent sound velocity has positive slope, which indicates tunneling of defects
Keywords :
barium compounds; high-temperature superconductors; superconducting transition temperature; ultrasonic propagation; ultrasonic velocity measurement; yttrium compounds; 0.01 to 300 K; 1 GHz; YBa2Cu3O7; anisotropic sound propagation; defects tunneling; discontinuous sound velocity; gigahertz ultrasound; high temperature superconductors; longitudinal phonons; mean field theory; single crystal superconductor; strain derivatives; superconducting transition; temperature region; Acoustic measurements; Acoustic propagation; Attenuation; Frequency; Magnetic films; Piezoelectric films; Superconducting coils; Superconducting transmission lines; Ultrasonic imaging; Zinc oxide;
Conference_Titel :
Ultrasonics Symposium, 1988. Proceedings., IEEE 1988
Conference_Location :
Chicago, IL
DOI :
10.1109/ULTSYM.1988.49544
