Title :
Ultrasonic nonlinearities of high temperature superconductor YBa 2Cu3O7-δ from 300 to 77 K
Author :
Breazeale, M.A. ; Jiang, W.H.
Author_Institution :
Nat. Center for Phys. Acoust., Mississippi Univ., MS, USA
Abstract :
The ultrasonic nonlinearity parameter β of the high-temperature superconductor YBa2Cu3O7-δ was measured from 300 to 77 K by using the second-harmonic generation technique. The ultrasonic nonlinearity parameter β decreases with decreasing temperature very rapidly from room temperature to 200 K and vanishes around the transition temperature. The phenomenon can be explained by assuming a structural phase transition, a superconducting transition or a gain boundary change. The behavior is unique and different from that of single crystals
Keywords :
barium compounds; harmonic generation; high-temperature superconductors; nonlinear acoustics; superconducting transition temperature; yttrium compounds; 300 to 77 K; YBa2Cu3O7-δ; gain boundary change; high temperature superconductor; second-harmonic generation technique; structural phase transition; superconducting transition; temperature dependence; transition temperature; ultrasonic nonlinearity parameter; Acoustic measurements; Ceramics; Crystals; Granular superconductors; High temperature superconductors; Nonlinear equations; Superconducting transition temperature; Temperature dependence; Ultrasonic variables measurement; Velocity measurement;
Conference_Titel :
Ultrasonics Symposium, 1990. Proceedings., IEEE 1990
Conference_Location :
Honolulu, HI
DOI :
10.1109/ULTSYM.1990.171572
