Bulk Wave Characterization of High Tc Superconductors
Abstract
The objective of this research is to characterize high T(c) superconductors with ultrasonic waves. A peak in ultrasonic attenuation has been observed at the superconducting phase transition of the thalium superconducting compound with a T(c) = 103 K. The position of this peak is independent of frequency and therefore should not be produced by a relaxation mechanism. It may be produced by interactions with fluctuations associated with the superconducting phase transition. The magnitude of the peak decreases in magnetic fields up to 6 Tesla. This appears to be the first time that an attenuation effect has been observed which is directly associated with the superconducting state of a high T(c) superconductor. Shear waves propagating parallel to the Copper Oxide planes and polarized in the CuO planes of a sinter forged YBa2Cu3O7 sample exhibit only one maximum in attenuation at around 180 K. Velocity measurements in the copper free high T(c) superconductors Ba(1-x)K(x) BiO3 show a definite change in slope at the phase transition. Measurements in the heavy Fermion superconductor UPt(3) show a 40 ppm change in velocity around 4.5 K, its antiferromagnetic phase transition temperature.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1989
- Accession Number
- ADA214030
Entities
People
- Bimal Sarma
- Moises Levy
Organizations
- University of Wisconsin–Milwaukee