Anisotropic sound propagation at 1 GHz in single-crystal YBa2Cu3O7 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.
|Number of pages||5|
|Journal||Ultrasonics Symposium Proceedings|
|State||Published - 1 Dec 1988|
|Event||IEEE 1988 Ultrasonics Symposium - Proceedings - Chicago, IL, USA|
Duration: 2 Oct 1988 → 5 Oct 1988