FLUX-FLOW AND PHASE-SLIP RESISTIVITY IN 2-PHASE POLYCRYSTALLINE BI1.6PB0.4SR1.7CA2CU3OX

Using a contact-less microwave technique, with an applied magnetic field varying to a maximum of 1.9 T, flux-flow and phase-slip resistivity are observed in a microsyntactically intergrown two-phase superconductting sample of nominal composition Bi1.6Pb0.4Sr1.7Ca2Cu3Ox. ''Stretched exponential'' response with beta = 1/3 is observed in the phase-slip resistivity. The onset temperature for the high-temperature phase is 106.5 K, while the lower-temperature phase manifests itself at 71 K. Flux-flow is observed superimposed on an isotropic background phase-slip resistivity, and is locally maximal several degrees below each transition temperature. Flux-flow resistivity, a consequence of the Lorentz force on a fluxoid, varies as sin2 (psi), where psi is the angle between the applied magnetic field and the r.f. current.