High-field temperature-dependent transport in polycrystalline Tl-Ba-Ca-Cu-O

Abstract

A phenomenology describing transport measurements in Bi-Sr-Ca-Cu-O is employed to describe high-field resistivity data on polycrystalline Tl-Ba-Ca-Cu-O. The data are also compared to the thermally activated flux-flow model given by Krause et al. (Physica C 205 (1993) 99) in which the activation energy was found to scale as U ∝ ( H cos θ) -α with α≅ 1 3 . The thallium data, taken with H ‖ J , show no evidence for conventional flux flow which varies as B/ H c2, or for thermally activated flux flow; the model presented features phase slip in a network of Josephson junctions. The resistivity is seen to vary as ϱ ps (B, T, θ) = ϱ n/ [ I 0(γ β( B, T, θ)/2)] 2 with β = 1 3 , and γ ≈ A T T c / ( TB | cos ( θ) | ). The field-dependent polycrystalline resistivity data are dominated by crystallites with θ ≅ 0 relative to the field direction. The 1 3 power is characteristic of a one-dimensional energy barrier.