FLUX DYNAMICS AND C-AXIS RESISTIVE DISSIPATION IN THE MIXED-STATE OF HIGH-TEMPERATURE SUPERCONDUCTORS - THE CASE OF (LA1-XSRX)(2)CUO4

We take the single-crystalline (La1-xSrx)(2)CuO4 system (x = 0.068) as an example to study flux dynamics in the mixed state of high-T-c supe rconductors by systematically measuring its c-axis resistivity, rho(c) , as a function of temperature, magnetic-field intensity and magnetic- field orientation with respect to the ab-plane. We firstly show the ex perimental evidence that excludes the contribution of Lorentz force dr iven flux motion to the c-axis resistive dissipation. Furthermore, we argue that neither the vortex dynamics for conventional anisotropic su perconductors nor the two-dimensional pancake vortices model is approp riate for the present system. We then demonstrate the difficulty of th e previously considered Lorentz force free dissipation models in expla ining the present experimental observations. Finally, a phenomenologic al model is introduced, in which the phase slippage model developed by Ambegaokar and Halperin is extended to the case of the c-axis resisti vity by taking into account the following two main features: (1) the i ntrinsic layered structures along the c-axis, and (2) the irreversibil ity line, T-irr(H), corresponding to a vortex glass-liquid transition. To show the advantages of the present model, we compare the model wit h the experimental rho(c)(T, H) data for H parallel to c, which gives excellent agreement in almost the whole transition region (five decade s).