Eleventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. IV France 06 (1996) C8-497-C8-500
Internal Friction of Flux Motion in Hg-System High-Tc SuperconductorsW. Tian, J.S. Zhu, H.M. Shao, J. Li and Y.N. Wang
National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
The internal friction(IF) and modulus as functions of temperature were measured for several Hg-system high-Tc superconductors(Hg1201, Hg1223, Hg1223 doped with Fe and Pb), under the applied magnetic field, with vibrating reed technique. An IF peak associated with flux motion can be found below Tc for all samples. The temperature of the IF peak increases with reducing vibrating amplitude. This amplitude dependence of IF indicates that the flux motion is characterized by nonlinear behavior. No apparent shift of IF peak position can be detected by varying the frequency in the range from 102Hz to 103 Hz. Furthermore, the IF peak height satisfies a scaling law Q-1 α ω-n. This may be originated from phase transition of flux line lattice(FLL) rather than a thermally activated diffusion process.
© EDP Sciences 1996