No abstract

No abstract

No abstract

Wan, Hebboul, and Garland Reply: The theoretical work of Horovitz [l] concludes that our recent measurements in BizSrzCaCuzOs-~(BSCCO) [2] can be interpreted in terms of a fluxon transition. His predictions seem to be consistent with our main findings, namely, the existence of two transition temperatures and a pronounced peak in the secondary voltage. A key feature of the Horovitz theory, ho~ever, is the existence of "fluctuating" fluxons which mediate the coupling between thermally excited vortices on adjacent CuO bilayers. Since fluxons are a consequence of the Josephson interaction, his theory also appears to be consistent with our general interpretation of the data. Clearly, more work is needed to establish the exact role of vortex and fluxon excitations in these layered superconductors.

Random percolative disorder has been introduced into 300x300 arrays of Nb-Au-Nb proximitycoupled junctions. Our measurements of dc transport properties show that large amounts of random disorder, although depressing Tc and broadening the resistive transition, do not alter the scale invariance of the phase transition. These results are described by a model which rescales the Josephson lattice by the percolation correlation length. The relevance of the observations to granular thin films is discussed.