Anisotropic energy dissipation in high-Tc ceramic superconductors: Local-field effects

In a recent communication Ji, Rzchowski, and Tinkham have interpreted the history dependence of the microwave surface resistance in polycrystalline YBa2Cu3O7- in terms of granularity and flux flow. In this paper we show that the proposed model can be extended to understand the hysteretic dissipation, found in polycrystalline superconductors through I-V dc curves, for the case where the magnetic field lies parallel and antiparallel to the transport current.