Mixed-State Hall Effect in an Extreme Type-II Superconductor

Measurements of mixed-state transverse and longitudinal voltages at T=1.2^∘K, $0<H<39$ kG, $0<J<800$ A/cm² on an extremely high-κ type-II alloy superconductor Ti-16 at.% Mo (κ=68, Tc=4.2^∘K, zero-temperature upper critical field Hc20=63 kG) show that the high-J, nearly J-independent, mixed-state Hall-angle tangent tanθₘ(H) is much larger than the normal-state value tanθₙ(H). At the highest applied magnetic field, the reduced Hall-angle tangent Pₘ(HHₖ₂₀=0.35)=[tanθₘ(H=39 kG)][tanθₙ(Hₖ₂₀)]≈0.6, where Hₖ₂₀=111 kG is determined by the measured reduced flux-flow resistivity ρf(H)ρₙ=HHₖ₂₀. This contrasts with previous results pertinent to pure or low-κ materials where Hₖ₂₀≈Hc20:Pₘ(0.35)≈0.35 (Bardeen-Stephen theory), (1) (Nozi\`eres-Vinen theory), 0.35 (Nb measurements of Fiory and Serin), (2) (Nb-Ta measurements of Niessen et al.).