Author: Moises LevyPublisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
Ultrasonic techniques have been used to characterize properties of high T sub c and other unconventional superconductors. Attenuation and velocity measurements with shear waves have been performed on a sintered sample of HgBa2CuO4 and single crystal and melt textured samples of YBCO as a function of magnetic field. Anomalous behavior is observed which may be due to the fact that sound waves are sensitive to the total number of flux lines sampled, regardless of their orientation. A pontoon technique was used to launch surface acoustic waves SAW through a single crystal platelet of YBCO. A relative maximum in attenuation is observed at around 90K which may be associated with a relaxation process. Measurements on a SAW reflective array compressor made of superconducting YBCO appear to indicate that the YBCO reflecting chevrons are more effective in reflecting the SAW in the normal state than in the superconducting state. The insertion loss of a SAW delay line made with YBCO interdigital electrodes decreased when the electrodes became superconducting. A theoretical model has been developed to quantitatively explain these results.
